Materials & Methods of Construction - CE145

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Materials & Methods of Construction - CE145
Chapter No 1
Bricks
Brick is obtained by moulding good clay into a block, which is dried and then burnt. This is the
oldest building block to replace stone. Manufacture of brick started with hand moulding, sun
drying and burning in clamps. A considerable amount of technological development has taken
place with better knowledge about to properties of raw materials, better machinaries and
improved techniques of moulding drying and burning.
The size of the bricks are of 90 mm × 90 mm × 90 mm and 190 mm × 90 mm × 40 mm. With
mortar joints, the size of these bricks are taken as 200 mm × 100 mm × 100 mm and 200 mm ×
100 mm × 50 mm. However, the old size of 8
3"
4
x 4
1
2
x 2
5"
8
giving a masonry size of 9” x 4
1
2
x 3”
is still commonly used in india.
Types of Bricks – Detail Classification of Bricks
Bricks are a regular size rectangular unit. Bricks are made of clay. They are usually used for most
of the building works. Bricks are most generally used as a substitute for stone when the stone is
not available.
Types of Bricks
Bricks can be of many types depending on –
1. Quality
2. Building Process

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3. Manufacturing Method
4. Raw Material
5. Using Location
6. Weather-resisting Capability
7. Purpose of Using
8. Shape
9. Region
Classification of Bricks Based on Quality
On the basis of quality, Bricks are of the following kinds:
First Class Brick: The size is standard. The color of these bricks is uniform yellow or red. It is well
burnt, regular texture, uniform shape. The absorption capacity is less than 10%, crushing
strength is, 280kg/cm2 (mean) where it is 245 kg/cm2 (minimum). It doesn’t have
efflorescence. It emits a metallic sound when struck by another similar brick or struck by a
hammer. It is hard enough to resist any fingernail expression on the brick surface if one tries to
do with a thumbnail. It is free from pebbles, gravels or organic matters. It is generally used-
 in a building of long durability, say 100 years
 for building exposes to a corrosive environment;
 for making coarse aggregates of concrete.
Second Class Brick: The size is standard, color is uniform yellow or red. It is well burnt, slightly
over burnt is acceptable. It has regular shape; efflorescence is not appreciable. The absorption
capacity is more than 10% but less than 15%. Crushing strength is 175kg/cm2(mean) where the
minimum is 154 kg/cm2. It emits a metallic sound when struck by another similar brick or struck
by a hammer. It is hard enough to resist any fingernail expression on the brick surface if one
tries to do with a thumbnail. It is used for the construction of one-storied buildings, temporary
shed when intended durability is not more than 15 years.
Third Class Brick: The shape and size are not regular. The color is soft and light red colored. It is
under burnt, slightly over burnt is acceptable. It has extensive efflorescence. The texture is non-
uniform. The absorption capacity is more than 15% but less than 20%. The crushing strength is
140kg/cm2(mean) where the minimum crushing strength is 105kg/cm2. It emits a dull or blunt
sound when struck by another similar brick or struck by a hammer. It leaves fingernail
expression when one tries to do with the thumbnail.
Classification of Bricks Based on Building Process
On the basis of the building process Bricks are of following kinds:

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1. Unburnt Bricks: These are half burnt bricks. The color is yellow. The strength is low.
They are used as surki in lime terracing. They are used as soiling under RCC footing or
basement. Such bricks should not be exposed to rainwater.
2. Burnt Bricks: Burnt bricks are made by burning them in the kiln. First class, Second Class,
Third Class bricks are burnt bricks.
3. Over Burnt or Jhama Brick: It is often known as the vitrified brick as it is fired at high
temperature and for a longer period of time than conventional bricks. As a result, the
shape is distorted. The absorption capacity is high. The strength is higher or equivalent
to first class bricks. It is used as lime concrete for the foundation. It is also used as
coarse aggregate in the concrete of slab and beam which will not come in contact with
water.
Classification of Bricks Based on Manufacturing Method
On the basis of manufacturing method bricks are of following kinds:
1. Extruded Brick: It is created by forcing clay and water into a steel die, with a very
regular shape and size, then cutting the resulting column into shorter units with wires
before firing. It is used in constructions with limited budgets. It has three or four holes
constituting up to 25% volume of the brick.
2. Molded Brick: It is shaped in molds by hand rather being in the machine. Molded bricks
between 50-65mm are available instantly. Other size and shapes are available in 6-8
weeks after the order.
3. Dry pressed Brick: It is the traditional types of bricks which are made by compressing
clay into molds. It has a deep frog in one bedding surface and shallow frog in another.
Classification of Bricks Based on Raw Materials
On the basis of raw materials bricks are of following kinds:
1. Burnt Clay Brick: It is obtained by pressing clay in molds and fried and dried in kilns. It is
the most used bricks. It requires plastering when used in construction works.
2. Fly ash clay Brick: It is manufactured when fly ash and clay are molded in 1000 degree
Celsius. It contains a high volume of calcium oxide in fly ash. That is why usually
described as self-cementing. It usually expands when coming into contact with
moisture. It is less porous than clay bricks. It proved smooth surface so it doesn’t need
plastering.
3. Concrete Brick: It is made of concrete. It is the least used bricks. It has low compression
strength and is of low quality. These bricks are used above and below the damp proof
course. These bricks are used can be used for facades, fences and internal brickworks
because of their sound reductions and heat resistance qualities. It is also
called mortar brick. It can be of different colors if the pigment is added during
manufacturing. It should not be used below ground.

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4. Sand-lime Brick: Sand, fly ash and lime are mixed and molded under pressure. During
wet mixing, a chemical reaction takes place to bond the mixtures. Then they are placed
in the molds. The color is greyish as it offers something of an aesthetic view. It offers a
smoother finish and uniform appearance than the clay bricks. As a result, it also doesn’t
require plastering. It is used as load bearing members as it is immensely strong.
5. Firebrick: It is also known as refractory bricks. It is manufactured from special designed
earth. After burning, it can withstand very high temperature without affecting its shape,
size, and strength. It is used for the lining of chimney and furnaces where the usual
temperature is expected to be very high.
Classification of Bricks Based on Using Location
On the basis of using location bricks are of following kinds:
1. Facing Brick: The façade material of any building is known as facing brick. Facings bricks
are standard in size, are stronger than other bricks and also have better durability. The
color is red or brown shades to provide a more aesthetic look to the building. There are
many types of facing bricks which use different techniques and technology. Facing bricks
should be weather resistant as they are most generally used on the exterior wall of
buildings.
2. Backing Brick: These types of brick don’t have any special features. They are just used
behind the facing bricks to provide support.
Classification of Bricks Based on Weather-resisting Capability
On the basis of weather-resisting capability bricks are of following kinds:
1. Severe Weather Grade: These types of bricks are used in the countries which are
covered in snow most of the time of year. These bricks are resistant to any kind of
freeze-thaw actions.
2. Moderate Weather Grade: These types of bricks are used in the tropical countries. They
can withstand any high temperature.
3. No Weather Grade: These bricks do not have any weather resisting capabilities and
used on the inside walls.
Classification of Bricks Based on Their Using
There are many uses of bricks. On the basis of the purpose of their using bricks are of following
kinds:
1. Common Bricks: These bricks are the most common bricks used. They don’t have any
special features or requirements. They have low resistance, low quality, low
compressive strength. They are usually used on the interior walls.
2. Engineering Bricks: These bricks are known for many reasons. They have a high
compressive strength and low absorption capacity. They are very strong and dense.

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They have good load bearing capacity, damp proof, and chemical resistance properties.
They have uniform red color. They are classified as Class A, class B, class C. Class A is the
strongest but Class B is most used. They are used for mainly civil engineering works like
sewers, manholes, ground works, retaining walls, damp proof courses etc.
Classification of Bricks Based on Shape
On the basis of shape bricks are of following kinds:
1. Bullnose Brick: These bricks are molded into round angles. They are used for rounded
quoin.
2. Airbricks: These bricks contain holes to circulate air. They are used in suspended floors
and cavity walls.
3. Channel Bricks: They are molded into the shape of a gutter or channel. They are used in
drains.
4. Coping Bricks: They can be half round, chamfered, Saddleback, angled varied according
to the thickness of the wall.
5. Cow Nose Bricks: Bricks having double bullnose known as Cow Nose Bricks.
6. Capping Bricks: These bricks are used to cap the tops of parapets or freestanding walls.
7. Brick Veneers: These bricks are thin and used for cladding.
8. Curved Sector Bricks: These are curved in shape. They are used in arcs, pavements etc.
9. Hollow Bricks: These bricks are around one-third of the weight of the normal bricks.
They are also called cellular or cavity bricks. Their thickness is from 20-25mm. These
bricks pave the way to quicker construction as they can be laid quickly compared to the
normal bricks. They are used in partitioning.
10. Paving Bricks: These bricks contain a good amount of iron. Iron vitrifies bricks at low
temperature. They are used in garden park floors, pavements. These bricks withstand
the abrasive action of traffic thus making the floor less slippery.
11. Perforated Bricks: These bricks contain cylindrical holes. They are very light in weight.
Their preparation method is also easy. They consume less clay than the other bricks.
They can be of different shapes like round, square, rectangular. They are used in the
construction of the panels for lightweight, structures, and multistoried frame
structures.
12. Purpose Made Bricks: For specific purposes, these bricks are made. Splay and can’t
bricks are made for doors and window jambs. Engineering bricks are made for civil
engineering constructions such as sewers, manholes, retaining walls. Fire bricks are
made for chimneys and fireworks. Ornamental bricks are made to use for cornices,
corbels. Arch bricks are used in arcs.
Classification of Bricks Based on Region
On the basis of the region bricks are of following kinds:
1. Cream City Bricks: These bricks are from Milwaukee, Wisconsin.

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2. London Stock: These bricks are used in London.
3. Dutch: These are from the Netherlands.
4. Nanak Shahi Bricks: These are from India.
5. Roman: These are used in Roman constructions,
6. Staffordshire Blue Brick: These are from England.
Composition of a good brick earth:
Following are the constituents of a good brick earth:
(1) Alumina (Al2O3):
It is the chief constituent of a good brick earth. A content of about 20% to 30% is necessary to
form the brick earth of a good quality. It imparts plasticity to the earth so it helps in the
moulding of the brick earth.
If alumina is present in excess with inadequate quantity of sand then the raw bricks shrink and
warp during drying, on burning they become too hard. So it is important to have an optimum
content of alumina.
(2) Silica (SiO2):
It exists in the brick earth either free or combined. As free sand it is mechanically mixed with
clay and in combined form it exists in chemical composition with alumina. A good brick earth
should contain about 50% to 60% of silica.
The presence of this constituent prevents the shrinkage, cracking and warping of raw bricks. It
thus imparts uniform shape to the bricks. The durability of bricks depends upon proper
composition of silica in brick earth. The excess of silica destroys the cohesion b/w particles and
brick become brittle.
(3) Lime(CaCO3):
A small quantity of lime not more than 5% is desirable in good brick earth. It should be present
in very fine state, because even small particles of size of a pin-head can result in the flaking of
the brick.
The lime prevents shrinkage of the raw bricks, sand alone is infusible, but it slightly fuses at kiln
temperature in presence of lime. Fused sand acts as a hard cementing material for brick
particles.
The excess of lime causes brick to melt and therefore its shape is lost. The lumps of lime turns
into quick lime (CaO) after burning and this free lime can later react with water to form slaked
lime. This process is called slaking it may result in splitting of the brick into pieces.
(4) Oxide of Iron (Fe2O3):

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Iron oxide performs two functions, first it helps in fusing of the sand like lime and second it
provides the red color to the bricks. It is kept below 5 to 6% because excess of it may result in
the dark blue or black color of brick.
(5) Magnesia:
It is used to provide a yellow tint to the bricks. Its content is only about 1% or less.
Characteristics of Good Bricks
It is always desirable to use the best quality brick in constructions. Therefore, the Characteristics
of a good brick must be investigated. Generally good bricks possesses following properties-
 Bricks should be uniform in color, size and shape. Standard size of brick should be
maintained.
 They should be sound and compact.
 They should be free from cracks and other flaws such as air bubbles, stone nodules etc.
with sharp and square edges.
 Bricks should not absorb more than 1
⁄5 of their own weight of water when immersed in
water for 24 hours (15% to 20% of dry weight).
 The compressive strength of bricks should be in range of 2000 to 5000 psi (15 to 35
MPa).
 Salt attack hampers the durability of brick. The presence of excess soluble salts in brick
also causes efflorescence. The percentage of soluble salts (sulphates of calcium,
magnesium, sodium and potassium) should not exceed 2.5% in brunt bricks.
 Brick should not change in volume when wetted.
 Bricks should neither overburnt nor under-brunt.
 Generally, the weight per brick should be 6 lbs. and the unit weight should be less than
125 lbs. per cubic ft.
 The thermal conductivity of bricks should be low as it is desirable that the building built
with them should be cool in summer and warm in winter.
 Bricks should be sound proof.
 Bricks should be non-inflammable and incombustible.
 Bricks should be free from lime pitting.

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Compressive Strength of Brick
Bricks are mainly used in the construction of wall, floor, cornices, and arches. Brick chips are
also used as a substitute for stone chips in the concrete mix where a stone is not available or an
economic solution is preferred. In all the above-mentioned cases, compression load governs. Due
to this, the compressive strength of bricks is a very important parameter.
Specified Compressive Strength
According to BDS 2002
Grade Mean Strength (kg/cm2 ) Minimum Strength (kg/cm2 )
S 280 245
A 175 154
B 140 105
According to Indian Standard (IS 1077:1992)
Classification Average Strength (N/mm2) Average Strength (kg/cm2)
35 35 350
30 30 300
25 25 250
20 20 200
17.5 17.5 175
15 15 150
12.5 12.5 125

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Classification Average Strength (N/mm2) Average Strength (kg/cm2)
10 10 100
7.5 7.5 75
5 5 50
3.5 3.5 35
Compressive Strength Test of Bricks
The determination of Compressive Strength Test of Brick is carried out under the specification
of ASTM C67-03.
Sampling of Brick
 Selection of Test Specimen: Full-size representative bricks should be sampled randomly
to cover the whole range color, texture, and sizes from a shipment.
 Numbers of Test Specimen: At least 10 bricks should be chosen from each lot of
1000000 bricks or fraction thereof. For larger lots, five individual bricks should be
chosen from each lot of 500000 bricks or fraction thereof.
Each sample must be marked for identification purposes. Markings must not cover more than 5%
of the superficial area of the sample.
Weight determination
Drying
The test specimens should be dried in a ventilated oven at 230o
F to 239o
F (110o
C to 115o
C) for at
least 24 hours and until two successive weighting at intervals of 2 hours shows an increment of
loss not greater than 0.2% of the last previously determined weight of the specimen.
Cooling
After drying, the specimens need to be cooled in a drying room. The temperature must be kept
75+15o
F (24+8o
C), with a relative humidity between 30 and 70%.
Materials Used

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 Cement: Quick hardening cement
 Sand: Locally available good quality sand
 Capping Material: Capping is usually done either using gypsum or Sulphur clay mixture. For the
later, a mixture containing 40 to 60 weight % Sulphur, the remainder being fire clay or other
suitable inert material passing a No.100 sieve with or without plasticizer is used.
Apparatus
 Capping Mold: Four 1 inch (25.4 mm) square steel bars on the surface plate to form a
rectangular mold approximately ½ inch (12.7 mm) greater in either inside dimension than the
brick specimen used.
 Testing Machine
Test Procedure
Preparation of the Sample
Dry half bricks with full height and width of the unit and length equal to one half of the full
length of the unit + 1 inch (25.4 mm). Ends should be plane and parallel.
Capping the Specimen
1. If the surface which will become the bearing surfaces during the compression test is
recessed or paneled, the depressions have to be filled with a mortar composed of 1 part
by weight of quick-hardening cement and 2 parts by weight of sand. The specimens are
to be aged at 48 hours before capping them. Where the recess exceeds ½ inch (12.7
mm), a brick or tile slab section or metal plate is used as a core fill.
2. The capping mold is to be placed.
3. The Sulphur mixture is to be heated in a thermostatically controlled heating pot to a
temperature sufficient to maintain fluidity for a reasonable period of time after contact
with the surface being capped. Care is required to prevent overheating and the liquid is
to be stirred before using.
4. The mold should be filled to a depth of ¼ inch with molten Sulphur material. The surface
is to be placed in the liquid vertically.
5. The unit must remain undisturbed for minimum 2 hours until solidification.
Testing the Specimen
1. Brick specimens are to be tested flatwise. The specimen is to be centered under the
spherical upper bearing within 1/16 inch.

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Figure:
Compressive Strength Test of Brick
2. The load should be applied up to one half of the expected maximum load, at any
convenient rate. Then the remaining load has to be applied at a uniform rate in 1-2
minutes.
Calculation:
Compressive Strength, C= (W/A)
Where,
W= Calibrated maximum load
A= Average of the gross areas of the upper and lower bearing surfaces of the
specimen.
Uses of Bricks
Brick plays very important role in the field of civil engineering construction. Bricks are used as
an alternative of stones in construction purpose. Here some main uses of construction brick are
given below.
 Construction of walls of any size
 Construction of floors
 Construction of arches and cornices
 Construction of brick retaining wall
 Making Khoa (Broken bricks of required size) to use as an aggregate in concrete
 Manufacture of surki (powdered bricks) to be used in lime plaster and lime concrete
Properties of Bricks.

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The essential properties of bricks may be conveniently discussed under the following four
headings: physical, mechanical, thermal and durability properties.
(1) Physical Properties of Bricks.
These properties of bricks include shape, size, color, and density of a brick.
(i) Shape.
The standard shape of an ideal brick is truly rectangular. It has Well defined and sharp edges.
The surface of the bricks is regular and even.
Special purpose bricks may, however, be either cut or manufactured in various other shapes.
These are generally modifications of rectangular shapes.
(ii) Size.
The size of brick used in construction varies from country to country and from place to place in
the same country. In India, the recommended standard size of an ideal brick is 19 x 9 x 9 cm
which with mortar joint gives net dimensions of 20 x 10 x 10 cm.
These dimensions have been found very convenient in handling and making quantity estimates.
Five hundred such bricks will be required for completing 1 m3 brick masonry.
It may be interesting to note that in U.K, U.S, the commonly used bricks have following
dimensions: The Standard size of Brick in India, US, UK.
Country Length (cm) Thickness (cm) Height (cm)
Standard Size of Brick in UK. 20 9.5 5.5
Standard Size of Brick in US. 20 10 10
Standard Size of Brick in India. 19 9 9
(iii) Color.
The most common color of building bricks falls under the class RED. It may vary from deep red
to light red to buff and purple. Very dark shades of red indicate over burnt bricks whereas
yellow color is often indicative of under-burning.
(iv) Density.
The density of bricks or weight per unit volume depends mostly on the type of clay used and
the method of brick molding (soft-mud, Stiff-mud, hard-pressed etc.).
In the case of standard bricks, density varies from 1600 kg/cubic meter to 1900 kg/cubic meter.
A single brick (19 x 9 x 9 cm) will weigh between 3.2 to 3.5 kg. depending upon its density.
(2) Mechanical Brick Properties.
Under this heading of properties of bricks, compressive strength and flexure strength are
included.
(i) Compressive Strength of Bricks.
It is the most important property of bricks especially when they are used in load-bearing walls.
The compressive strength of a brick depends on the composition of the clay and degree of
burning. It may vary from 35 kg/cm2 to more than 200 kg/cm2 in India.

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It is specified under the I.S.S. codes that an ordinary type building brick must possess a
minimum compressive strength of 35 kg/cm2. The first and 2nd class bricks shall have a
compressive strength not less than 70 kg/cm2 and 140 kg/cm2 respectively.
(ii) Flexure Strength.
Bricks are often used in situations where bending loads are possible in a building. As such, they
should possess sufficient strength against transverse loads. It is specified that the flexural
strength of a common building brick shall not be less than 10 kg/cm2. Best grade bricks often
possess flexural strength over 20 kg/cm2. Similarly, it is required that a good building brick shall
possess a shearing strength of 50-70 kg/cm2.
(3) Thermal Properties of Building Bricks.
Besides being hard and strong, ideal bricks should also provide an adequate insulation against
heat, cold and noise. The heat and sound conductivity of bricks vary greatly with their density
and porosity. Very dense and heavy bricks conduct heat and sound at a greater rate. They have,
therefore, poor thermal and acoustic (sound) insulation qualities. For this reason, bricks should
be so designed that they are light and strong and give adequate insulation.
(4) Durability.
By durability of bricks, it is understood that the maximum time for which they remain unaltered
and strong when used in construction. Experience has shown that properly manufactured
bricks are among the most durable of man-made materials of construction. Their life can be
counted in hundreds of years. The durability of bricks depends on some factors such as:
absorption value, frost resistance, and efflorescence.
(i) Absorption Value.
This property is related to the porosity of the brick.
True Porosity is defined as the ratio of the volume of pores to the gross volume of the sample
of the substance. Apparent porosity, more often called Absorption value or simply absorption,
is the quantity of water absorbed by the (brick) sample. This is expressed in percentage terms
of the dry weight of the sample:
Absorption=W2 – W1 / W1 x 100
Where W2 is weight after 24 hours of immersion in water and W1 is the oven dry weight of the
sample. The absorption values of bricks vary greatly. It is, however, recommended that for first
class bricks, they shall not be greater than 20 percent and for ordinary building bricks, not
greater than 25 percent. The absorption characteristic of bricks effects their quality in many
ways:
Firstly: higher porosity means less solid materials; hence, strength is reduced.
Secondly: higher absorption will lead to other water-related defects such as frost-action and
efflorescence.
Thirdly: higher absorption results in deeper penetration of water which becomes a source of
dampness.
(ii) Frost Resistance.

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Water on freezing expands by about 10% in volume and exerts a pressure on the order of 140
kg/cm2. When bricks are used in cold climates, their decay due to this phenomenon of “frost
action” may be a common process. This is especially so because bricks are quite porous
materials (apparent porosity = 20-25%). It is, therefore, essential that bricks in these areas
should be properly protected from rain to minimize absorption.
(iii) Efflorescence.
It is a common disfiguring and deteriorating process of bricks in hot and humid climates.
Brick surface gets covered with white or gray colored patches of salts. These salts are present in
the original brick clay. When rain water penetrates into the bricks, the salts get easily dissolved.
After the rains, evaporation starts. The salts move out along with the water and form thin
encrustations on the surface of the bricks. Salts which are commonly precipitated during
efflorescence are: sulfates of calcium, magnesium, sodium and potassium. It is why great
emphasis should be laid while testing the chemical composition of the clay for brick
manufacturing.
SUMMARY (Properties of Bricks).
1. It should have a rectangular shape, regular surface and red colored appearance.
2. It should confirm in size to the specified dimensions (19 x 9 x 9 cm).
3. It should be properly burnt. This can be ascertained by holding two bricks freely, one in each
hand, and striking them. A sharp metallic sound indicates good burning whereas a dull thud
would indicate incomplete burning.
4. A good building brick should not absorb water more than 20 percent of its dry weight.
Absorption should not exceed 25 percent in any case.
5. A good building brick should possess requisite compressive strength, which in no case should
be less than 35 kg/cm2. A rough test for the strength of the brick is to let it fall freely from a
height of about one meter on to a hard floor. It should not break.
6. Brick should be hard enough so that it is not scratched by a finger nail.

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7. A good brick has a uniform color and structure through its body. This can be checked by
taking a brick from the lot and breaking it into two parts. The broken surface in both the halves
should have same appearance and structure.
Special Types of Bricks:
Ordinary building bricks are typically rectangular in shape, solid in structure and made from a
Suitable type of brick-clays.
In building construction, however, bricks of modified Shapes, porous or hollow structure and
also made from materials other than clay are also sometimes used.
A familiarity with this Special classification of bricks is quite important for a construction
engineer and an architect. We Shall discuss them below.
Classification of Bricks Based on Modification in Shape.
In construction, there are positions where a perfect rectangular shape brick will not be suitable.
It has to be modified.
Such bricks are required in the plinth, the corners of the walls and at the copings.
There is a long list of such Special-Shaped bricks… We will discuss the important ones here.
i. Squint Brick:
They are cut on one corner at an angle of other than 90 degrees. They are required for giving
shape to an exterior or interior corner in a wall.
ii. Splay or Can Brick:
These have a level or portion taken off, width wise, length wise, or in both directions. The
various shapes grouped under splay bricks are made for use in jambs of doors and windows and
also in plinths.
iii. Coping Bricks:
They are used for coping on walls in order to give them a nice appearance and also for easy
drainage of water.
When a coping is to be provided to a wall, a special shape may be desired. The chamfered, the
half round, and the saddleback bricks are some common coping bricks.
iv. Bullnose:
Bullnose bricks are used at turns of the wall so that round corners are obtained. It is a standard
brick having one edge rounded.

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v. Cownose:
It is similar to bullnose, but it has both edges rounded on one side. It may also be called double
bullnose bricks. They have the same use as bullnose, but they just give additional roundness.
Classification of Bricks based on Cavities:
Three types of bricks shall be discussed under this category.
i. Perforated Bricks:
These form a modem class of building bricks that have many advantages over the ordinary solid
brick. In perforated bricks, cylindrical, rounded or rectangular holes are made in the bricks after
the molding stage. These holes are called perforations.
They are properly spaced from the side of the brick, and the minimum distance is 15 mm.
Further, a distance between any two perforations is not less than 10 mm.
The volume of the perforations may be as much as 20 – 50 percent of the total volume of the
brick. They may be larger in size than ordinary building brick which is a distinct advantage in
that work output of a Mason will increase considerably with the use of perforated bricks.

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The
major advantages that perforated bricks offer over ordinary bricks are:
(i) They are light in weight.
(ii) Less quantity of clay is required for their manufacture.
(iii) Less time is required for drying and burning of perforated bricks.
(iv) These offer better resistance against rain penetration and better insulation against heat. As
such they are ideally suited for tropical countries.
(v) Efflorescence is least in perforated bricks.
(vi) These are especially suitable for the construction of brick panels in multi-story structures.
Perforated bricks have as yet to find popularity in all countries although they are already widely
used in Germany, France, and America.
Already there is a trend for their use.
The manufacture of perforated bricks requires slightly sophisticated technology, and that is the
main reason for lesser use in all over the world.
ii. Hollow Bricks:
Hollow bricks also called cavity bricks or cellular bricks they have well-defined sets of cavities
with specified dimensions made in the body of the brick.
As a result, their net weight may be only one-third to one-half of the solid portion. It is
important that the thickness of the brick wall near the cavity should not be less than 2 cm.
The hollow bricks are made from a special type of brick clay (which should have higher clay
content).
They offer the following advantages over the ordinary types of bricks.
(i) Being light in weight, they can be handled more conveniently, and the output of the mason
may be three to four times compared to ordinary bricks.
(ii) They offer better insulation against heat and sound.
(iii) They are ideal and economical for non-load-bearing walls, e.g., in partition walls.

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iii. Channel OR Gutter Bricks:
They are actually special purpose bricks baring a continuous central semi-circular cavity or
depression running through their length.
Very often they are glazed to make them impervious: They are mostly used in the laying of
drains.
Classification of Bricks Based on Composition:
We will discuss 2 major classification of bricks here below.
i. Sand LIME Bricks:
Definition. These are building bricks made from sand and lime as the raw materials instead of
clay. The clay content may be only negligible.
They differ from ordinary clay bricks not only in composition but also in the method of
manufacture. They are, however, similar in shape and size to the ordinary types of bricks.
Manufacture. The principal raw materials for sand-lime bricks are:
(1) Sand. It must be free from harmful impurities like chloride, iron oxides, black minerals and
organic matter. Sand forms around 90 percent of sand-lime bricks.

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(ii) Lime. It is used in the form of a slaked (hydrated) lime. Its content varies from 8-12 percent.
The slaked lime used for brick making has high calcium-content and should be free from
magnesium.
Besides the two essential components, some clay (up to four percent) in finely divided form is
desirable. Pure, salt-free water (not sea water) is another requirement.
For giving a required color to the sand-lime bricks, some pigments are added in small
percentages to the ingredients at the mixing stage.
Among these pigments, the following are used Commonly;
Iron-oxides for red and brown color.
Chromium Oxide for green color.
Ochre for yellow color.
Carbon black for Grey and black color.
Molding. After mixing the finely powdered raw materials in the desired proportion, a damp
mixture is obtained adding 2-3 per cent clean water.
From this damp mixture, brick-shaped units are molded using ROTARY PRESS. Pressures applied
range from 300-600 kg/cm2.
Such high-pressure results in highly compressed and dense sand-lime bricks which are almost
dry at this stage.
Autoclaving. The molded units are put into an autoclave (a steel cylinder with the closed end
where heating is done by steam under pressure).
In the autoclave, the bricks are treated for 6-12 hours under steam pressures between 8-16
kg/cm2. It is in the autoclave that sand and lime react chemically and form a chemical
compound, calcium-silicate. That is the chemical composition of the sand-lime brick.
The sand-lime bricks taken out from the autoclave are ready for use.
Properties of Sand Lime Bricks.
(i) The sand-lime bricks have a very smooth and uniform finish and a pleasing appearance.
(ii) They are quite dense, strong and hard.
(iii) They are least porous and hence free from efflorescence.
Because of these properties, sand-lime bricks offer many advantages.
(i) They are uniform in shape, size and finish and hence require no plastering.

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(ii) The quantity of plaster when required is quite less because of the smooth surface of the
brick.
(iii) They are water repelling and hence free from absorption related defects of ordinary bricks.
(iv) Since the materials required for sand-lime bricks are also quite common in occurrence,
these can provide a suitable alternative to clay-bricks.
We should know that most clay used in making bricks is from agricultural lands and hence its
conservation will help in increasing food production.
Among the major disadvantages of sand-lime bricks, the following may be mentioned:
(i) They can be manufactured only by using mechanized methods. Hence their production at
village levels is almost impossible at present.
(ii) They are unsuitable for foundations and paving uses. In the first case, they get damaged in
the presence of water, and in the second case, it is because they have poor resistance to
abrasion.
The Scope of Use. In Western countries, sand-lime bricks are used quite widely. Sooner or later,
they will have to be introduced in other countries too on a large scale.
ii. Fire OR Refractory BRICKS:
Definition. This is a separate group of bricks which is capable of withstanding in very high
temperatures without undergoing any deformation in shape or size and without reacting with
the material of a particular composition.
Their use is restricted to the making of inner walls of furnaces for the manufacture
of metals and for similar high-temperature applications.
Classification:
The firebricks are classified on the basis of their reactivity towards melts at high temperatures:
(a) Acidic Bricks. They are resistant to the melts of acidic composition (but will react with the
melts of basic composition).
Example: Fire-clay bricks, silica bricks.

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(b) Basic Bricks. They are resistant to the melts of basic composition. Hence they will not be
suitable for use in those furnaces where acidic melts are being heated.
Examples: Magnesia bricks, Bauxite bricks.
(c) Neutral Bricks. They are non-reactive to both the acidic and basic melts. Hence these find
applications in heating either type of melts.
Examples: Chromite bricks, Chrome-magnesite bricks.
Manufacture of Fire Bricks.
They are manufactured in the same manner as a building Brick. The four stages are involved in
their manufacture process are:
 Moulding
 Drying
 Burning
 Cooling
The Raw Materials are first crushed in to the required size and then blended are mixed
thoroughly in the presence of required quantity of water.
After this process Brick are molded manually or by using Machines such as “Presser “.
The molded Bricks are dried and then burnt in a very high temperature, generally between
1600 to 2000 Centigrade.
After this Process they are allowed to cool very gradually.
Description of important Fire Bricks or Refractory Bricks.
(a.) Fire Clay Bricks.
These constitute are an important class of refractory materials of acidic group. Raw material for
its manufacturing can withstand at very high temperatures without fusing or softening.
Such clay is often available under the coal layers in nature.
Silica (65-75 Percent) and alumina (25-35 Percent) are the two main constituents of Fire Clay.
They are free from impurities like oxides of calcium, magnesiumand iron. The maximum
permissible upper limit for all such impurities is 5 Percent.
These are manufactured in a manner similar to the common building Brick. The selected clay is
crushed to the fine powder and molded into the brick unit.
These are than dried and burnt in Continuous kiln at very high temperature (1600 to 1900
centigrade). They are cooled gradually before taking out from the kiln.
Types.
They are divided into three types on the basis of temperature.
High Duty. (1482 to 1648 Centigrade).
Medium Duty (1315 to 1481 Centigrade)
Low Duty (870 to 1314 Centigrade)
Properties.
They have high resistance to palling, high bearing capacity and low coefficient of thermal
expansion.
Uses.

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They are commonly used as a lining material in steel making furnaces and reverberatory
furnaces.
(b.) Silica Fire Bricks.
These are made up mostly of silica, which may range from 95 percent or above. The remaining
material is generally calcium oxide that act as binding agent. These are acidic in character. Their
raw materials are pure quartz (SiO2), or sandstone of high silica content. The molded unit are
burnt in about 1500 Centigrade. They are extensively used in Bessemer Converter as lining
material because slag in that case are acidic in nature.
(c.) Magnesite Fire Bricks.
They are classed among the basic refractories. There raw material is magnesium oxide. The
major source for it is Dolomite rock.
(d.) Bauxite Fire Brick.
They also form a very important class of Basic Refractories. They are made from the
rock Bauxite (Al2O32H2) which are mixed with some clay (Fire Clay type).
(e.) Chromite Fire Bricks.
They are belonging to the neutral class of refractories. Raw material used for these Fire Bricks is
a mineral called CHROMITE.
The mineral is double oxide of chromium and iron in its composition. These types Refractory
bricks are capable of resisting both the acidic and basic environments in a furnace.
These type of fire brick are commonly used in the steel making furnaces.
Functions of various constituents of brick-earth
Composition.

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A good brick-earth should be such that when prepared with water it can be easily moulded,
dried and burnt with out cracking or warping. It should contain a small quantity of finely divided
lime to help in binding the particles of brick together by melting the particles of sand. A little
oxide of iron should also be present which would give the brick its peculiar red colour and act in
the same manner as lime.
A good brick earth should preferably conform to the following composition:
Clay (Alumina) 20 to 30 per cent by weight
Silt 20 to 35 per cent by weight
Sand 35 to 50 per cent by weight
The total content of clay and silt should not as far as possible be less than 50% by weight.
functions of brick constituent
(i) Silica or Sand.
It is present either free as sand or in combination as silicate of alumina. Silica is in fusible except
at very high temperatures but in the presence of alumina in nearly equal proportions and the
oxide of iron to fuses at lower temperatures. Unlike silicate of alumina its presence in clay
produces hardness, resistance to heat, durability and prevents shrinkage and warping. Excess of
it makes the brick brittle.
(ii) Alumina.
It is a tenacious finely-grained mineral compound present in brick-earth. It is plastic, when wet,
and in capable of being molded to any shape. On drying it loses its plasticity and becomes hard,
shrinks, warps and cracks. Burning causes the fusion of its constituents thereby making it
homogeneous, harder and stronger.
(iii) Lime.
When present in small quantities in finely divided state it reduces shrinkage of bricks and acts
as a flux causing silica to melt. It results in binding the particles of brick together resulting in
greater strength of brick. Excess of lime causes the brick to melt and lose its shape.
(iv) Magnesia.
In the presence of iron, it gives a yellowish tint to the bricks. It should not be present in excess.
However, the presence of small quantity of manganese with iron will give the brick darker or
even black colour. Total lime and magnesia in case of alluvial soil shall not be more than one
per cent and in other cases it will preferably not exceed 15 per cent.
(v) Oxide of iron.
In the presence of silica and alumina, it helps the fusion of brick particle. Also it influences the
colour of bricks. It produces a tint varying from light yellow to red depending upon the
percentage of iron present in clay. Excess of it makes the colour dark blue. It should not be
present in the form of iron pyrites.
Harmful ingredients.
(i) Lime.
If present in excess, it melts the brick particles as a result of which the brick loses shape. Lime
should also be not present in brick-earth in the form of lime stone or kankar modules. On the

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burning of bricks, these get converted to quickline which expands on absorption of moisture
and causes the cracking and disintegration of bricks.
(ii) Iron pyrites.
Iron pyrites get oxidized in the brick, crystallize and split the brick to pieces. These should be
carefully removed from brick-earth.
(iii) Pebbles of stone and gravel etc.
Their presence makes it difficult to mix the brick-earth thoroughly as a result of which the bricks
are not homogeneous. It gives weak and porous bricks. Also such bricks cannot be readily cut or
worked.
(iv) Alkalies.
Their excessive presence in earth renders it unsuitable for bricks. These act as flux causing the
bricks to melt, twist and warp. Presence of common salt in earth taken from seashores or from
near salt formations has similar effects to those narrated above and also make the
bricks hygroscopic thereby causing efflorescence.
(v) Reh or Kallar.
It is the sulphate of soda mixed with a little carbonate of soda and common salt. Its presence in
brick earth prevents bricks from being properly burnt. After the bricks have been burnt these
salts recrystallize and appear as irregular and unsightly white patches on the surface of bricks.
They cause the plaster and the surface of bricks to peel-off layer by layer and to ultimately
crumble away. Presence of reh or kallar in soil could be easily detected by the presence of
efflorescence on the sides of fresh excavation, if the soil is moist.
Bricks are rectangular units of construction material. Bricks are used in masonry construction,
walls, and pavements. It is used as a substitute of stone, where the stone is not readily
available. Brick chips are often used as coarse aggregate in the concrete mix.

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Figure: Raw (Green) Bricks
Percentage of Constituents of Brick (Weight Basis)
There are six major ingredients of brick. The general percentage of these ingredients in brick is
given below:
Ingredient Percentage in
brick
Silica (SiO2) 55%
Alumina (Al2O3) 30%
Iron Oxide (Fe2O3) 8%
Magnesia (MgO) 5%
Lime(CaO) 1%
Organic Matter 1%
Chief Ingredients of Brick and Their Functions
Silica (Sand) and Alumina (Clay), these two are the most prominent ingredients in brick clay.
When mixed with water in proper proportions, it gains plasticity. The plastic mass can be easily
molded and dried. It should not go through cracking, shrinkage or warping.
Alumina
Alumina is the main constituent of clay. It acts as a cementing material in raw brick. Brick clay is
plastic due to the presence of alumina. This plasticity ensures that bricks can be molded. An
excess amount of alumina in clay may cause the bricks to shrink, warp or crack on drying and
burning as any other cementing material.
Figure: Clay for Brick formation
Silica
Good quality bricks contain 50-60% silica. It is present in both free and combined form. As frees
sand, it remains mechanically mixed with clay. In combined form, it reacts with alumina to form
aluminosilicates. Silica prevents raw bricks from cracking, shrinking and warping. The higher the
proportion of sand, the more and shapely and uniform in texture will be the brick. Although,

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excess silica destroys cohesion between the brick clay particles and makes brick brittle and
weak. The durability of bricks largely depends upon the proper proportion of silica and alumina.
Figure: Sand
Lime
Bricks should contain a little amount of finely powdered lime. It enables silica (of a required
portion) to melt at the furnace temperature of 1650oC and binds the particles of brick together
resulting in strong and durable bricks. At about 1100o C, lime acts as a catalyst to elevate the
furnace temperature to 1650oC at which silica fuses. This slightly fused silica works as a strong
cementing material. Excess lime in brick clay will cause vitrification of bricks. It causes bricks to
melt, as more than the required amount of silica will fuse. The bricks then lose their shape and
become disfigured.
Figure: Powdered Lime
Iron Oxide
Bricks contain a small quantity of Iron Oxide. Iron Oxide acts a flux like lime, thus helps silica to
fuse at low temperature. It imparts a red color to bricks upon burning. Iron also increases the
durability and impermeability of the bricks.

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Figure: Iron Oxide powder
Magnesia
A small proportion of magnesium decreases shrinkage and gives a yellow tint to the bricks. An
excess amount of it causes bricks to decay.
Harmful Ingredients of Brick
Lime
Excess lime melts the bricks and disfigures it. If CaCO3 exists (in the purest form, i.e., if it
contains at least 95% CaO) in lime-lump in brick clay, it converts into quicklime on burning.
When these bricks come in contact with water, quicklime slakes and expands. And causes
disintegration of bricks.
Alkalis
Alkalis are mainly salt of Sodium (Na) and Potassium (K). It acts as a flux in the kiln and causes
fusion, warping, and twisting of bricks. Alkalis absorb moisture from the atmosphere and cause
dampness & efflorescence in bricks (because of the presence of hygroscopic salts, e.g., CaCl2,
MgCl2, etc.).
Pebbles, Stones & Gravels
Their presence does not allow thorough mixing of earth, thus the bricks produced are weaker.
Such bricks cannot be broken at the desired section and they break very irregularly.

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Figure: Pebbles, Stones, and Gravels
Iron Pyrites (FeS)
Iron Pyrites causes crystallization & disintegration of bricks while burning. It discolors bricks in
the form of black slag.
Organic Matter
Organic matter in bricks makes bricks porous resulting in low density and weaker bricks.
Nomenclature of cut-bricks
Brick NomenclatureFrequently, the Builder must cut the brickinto various shapes. The most
common shapes are shown in figure 7-50. They are called half or bat,three-quarter closure,
quarter closure, kingclosure, queen closure, and split. They are usedto fill in the spaces at
corners and such other places where a full brick will not fit. The six surfaces of a brick are called
the cull, the beds, the side, the end, and the face, as shownin figure 7-51. Brick ClassificationA
finished brick structure contains FACEbrick (brick placed on the exposed face of the
structure) and BACKUP brick (brick placed behind the face brick). The face brick is often of
higher quality than the backup brick; however, the entire wall may be built of COMMON brick.

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Common brick is brick that is made from pit-run clay, with no attempt at color control and no
special surface treatment like glazing or enameling. Most common brick is red. Although any
surface brick is a face brick as distinguished from a backup brick, the term face brick is also used
to distinguish high-quality brick from brick that is of common-brick quality or less. Applying this
criterion, face brick is more uniform in color than common brick, and it may be obtained in a
variety of colors as well. It maybe specifically finished on the surface, and in any case, it has a
better surface appearance than common brick. It may also be more durable, as a result of the
use of select clay and other materials, or as a result of special manufacturing methods. Backup
brick may consist of brick that is inferior in quality even to common brick. Brick that has been
underburned or overturned, or brick made with inferior clay or by inferior methods, is often
used for backup brick. Still another type of classification divides brick into grades according to
the probable climatic conditions to which it is to be exposed. These are as follows: GRADE SW is
brick designed to withstand exposure to below-freezing temperatures in amorist climate
like that of the northern regions of the United States. GRADE MW is brick designed to withstand
exposure to below-freezing temperatures in a drier climate than that mentioned in the
previousparagraph. GRADE NW is brick primarily intended for interior or backup brick. It may
be used exposed, however, in a region where no frost action occurs, or in a region where frost
action occurs, but the annual rainfall is less than 15 in.
DIFFERENT CUTS AND ORIENTATIONS OF BRICKS USED IN CONSTRUCTION
1. BRICK ORIENTATION:
(i). HEADER:

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The shorter side or end face of a brick that is exposed is termed as header.
(ii). STRETCHER:
The longer narrow side or face of a brick that is exposed is termed as stretcher.
(iii). ROWLOCK:
The head is visible and the long narrow sides are on bottom and top.
(iv). ROWLOCK STRETCHER:

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When the thinner stretcher sides are on bottom and top faces on the sides.
(v). SAILOR:
The heads are on top and bottom and the stretcher faces are on the side. Mostly used for
decoration.
(vi). SOLDIER:
The stretcher side is visible and the heads are at the bottom and top. It is usually used for
decoration.

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2. DIFFERENT TYPES OF BRICK CUTS
1. CLOSER:
Closer is the small piece of brick cut lengthwise in such a manner that its one long face remains
uncut and used at the end of masonry wall to maintain bond pattern.
(i). QUEEN CLOSER (HALF):
When a brick is cut along its length, making it two equal pieces then it is called queen closer.
(ii). QUEEN CLOSER (QUARTER):
When a queen closer is cut in to two equal pieces then it is called as queen closer quarter.
(iii). KING CLOSER:

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King closer are the portion of a brick obtained by cutting off the triangular piece between
center of one end and the center of one side.
(iv). BEVELLED CLOSER:
Similar to king closer with the only difference that the whole length of the brick bevelled for
maintaining the half width at one end and full width at the other.
(v). MITRED CLOSER:
It is a brick whose one end is cut splayed or mitred for full width. The angle of splay vary from
45 to 60 degree.
2. BAT:
The portion of bricks cut across the width is termed as bat.

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(i). THREE QUARTER BAT:
It is the form of brick bat having its length equal to three quarter of length of a full brick.
(ii). HALF BAT:
If the length of the bat is equal to half the length of the full bricks.
(iii). BEVELED BAT:
A brick bat is called beveled bat when its width has beveled.
COLOURS OF BRICKS
The colours of bricks as obtained in its natural course of manufacture depend on the following
factors

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 Degree of dryness achieved before burning
 Natural colour of clay and its chemical composition
 Nature of sand used in moulding operation
 Quality of fuel used in burning operation
 Quantity of air admitted to the kiln during burning
 Temperature at which bricks are brunt
COLOURS OF BRICKS
No. Colour Constituents Present in Clay
1 Black Manganese and large proportion of iron
2 Bluish Green Alkalies
3 Bright red, dark blue or purple Large amount of iron oxide
4 Brown Lime in excess
5 Cream Iron and little lime
6 Red Iron in excess
7 White Pure clay
8 Yellow Iron and magnesia
The artificial colouring of bricks is achieved by adopting one of the following two methods
1. Addition of colouring material
2. Dipping in colouring liquid
1. Addition of Colouring Material:

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In this method the required colouring material is added in brick earth. The bricks prepared from
such earth will present the desired colour. The usual colouring materials are iron oxides,
manganese, French ultramarine, Indian red etc. This method is adopted when the colouring
material is cheap and when it is available in plenty.
2. Dipping in Colouring Liquid:
In this method an earthenware box which is slightly larger each way than a common bricks is
taken. It is filled nearly to 1/2 depth with liquid which is in the form of thick paste. The bricks to
be coloured are placed on an iron plate and with a fire underneath they are heated to such an
extent that they can be easily handled. One brick is taken at a time and it is allowed to stay for
few seconds in the box. It is then placed aside to dry.
The colouring liquid is formed by the addition of colouring material to a mixture of lineseed oil,
litharge and turpentine. The proportion of various component of colouring liquid for different
colours.
COLOURING LIQUID
Component
Name of the Colour
Black Blue Dark red Grey
Lineseed oil 1.20 N 570 c.c. 850 c.c. 0.60 N
Lintharge 0.60 N 0.15 N 1.15 N 0.30 N
Turpentine 1.80 N 570 c.c. 850 c.c. 1.20 N
Manganese 1.80 N - - 0.30 N
French ultramarine - 4.50 N - -
Indian red - - 0.15 N -
White lead - - - 0.90 N
Following are the advantage of this method-
1. The bricks which are coloured by this method do not lose their colours, when exposed
to the atmosphere.
2. It can be adopted for expensive colours
3. It is possible to develop a variety of colours cheaply and easily
4. The penetration of colouring liquid in ordinary bricks ia adbout 3 mm or so.

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5. This method can be used for brick wall which are already constructed. The wall surface
is carefully cleaned. The colouring liquid is slightly heated and it is applied on the wall
surface with a brush.
SIZE, WEIGHT AND FACTORS AFFECTING QUALITY OF BRICKS
SIZE AND WEIGHT OF BRICKS
The bricks are prepared in various sizes. The custom in the locality is the governing factor for
deciding the size of a brick. Such bricks are not standardized are known as the traditional bricks.
It bricks are large it is difficult to burn them properly and they become too heavy to be placed
with a single hand. On the other hand, if bricks are small more quantity of mortar is required.
For India a brick of standard size 190 mm x 90 mm x 90 mm is recommended by BIS. With
mortar thickness the size of such a brick becomes 20 mm x 10 mm x 10 mm and it is known as
the nominal size of the modular bricks. Thus the nominal size of brick includes the mortar
thickness.
It is found that the weight of 1 m3 of brick earth is about 18 KN. Hence the average weight of a
brick will be about 30 to 35 N.
FACTORS AFFECTING QUALITY OF BRICKS
Following factors affect the quality of bricks-
 Composition of brick earth
 Preparation of clay and blending of ingredient
 Nature of moulding adopted
 Care taken in drying and stacking of raw or green bricks
 Types of kiln used to include type of fuel and its feeding
 Burning and cooling processes
 Care taken in including
It is thus obvious that not only the bricks of different brick fields will have different strength,
but in the same brick field, the bricks of the same batch may have different strengths.
The average crushing strength and tensile strength of hand moulded bricks are 60000 KN/m2
and 2000 KN/m2 respectively. In practice however the bricks are not subjected to the tensile

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stresses. It may be noted that the strength of brickwork mainly depends on the types of mortar
used and not so much on the individual strength of the bricks.
How to check quality of Bricks on site?
Bricks are building blocks of a structure. Brick is most extensively used materials of the building
construction.
As an Engineer, you must know how to check the quality of bricks on site. A good quality of
brick should be chemically inert that means it won’t show any reaction when it mixed with any
material.
In this post, I am making you learn how to check the quality of bricks on site and what are the
qualities of a good brick.
To chose the right quality of brick one should test the brick for following tests: -
1. Uniform Color, Size, and Shape:
Colour & shape of Brick: -
A good quality of bricks should be well burnt and have a colour of rich red or Copper colour, any
other colour other than above resembles that brick is under burnt or over-burnt. If bricks are
over or under-burnt, then it loses it shape.
Size of Brick: -
Brick should be uniform in size it shouldn’t have any bulks on edges.
More the bulking in brick needs more mortar. It ultimately increases the cost of a building. A
good brick should be sharp at edges.
A good quality of bricks should have an accurate dimension whereas +/- 3 tolerance is allowed.
2. Hardness of brick: -

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Best quality of brick should resist the scratches against sharp things. Scratch the brick using
your fingernail or sharp tool. A good brick should not show any impression or scratch of a
fingernail on the brick.
3. Homogeneity: -
Break the brick and examine it. A good quality brick should be homogeneous, compact and with
zero lumps.
4. Water absorption: -
A good brick should absorb less than 20% of water when it is immersed in water for 24hrs. If
the brick absorbs more than the allowable limit. It absorbs water from cement mortar during its
bonding. This eventually affects the brick bonding strength.
Water absorption test on brick: -
To test the water absorption follow the below procedure:
Take a brick and weight it as (W1)
Now immerse the brick in water for 24 hrs. and then weight it as (W2)
Find out the percentage increase of brick weight by adopting below formula
Water absorption in the brick formula:
5.Check for efflorescence on bricks: -
Efflorescence is a salt deposit seen on the surface of bricks. Usually, it’s in white. This can be
visually inspected by checking white patches on the bricks surface, White patches on bricks
resemble presence of sodium and potassium salts on it which is not suitable for construction.

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Soils used in the manufacturing of bricks should free from sulphate, potassium and sodium. If
brick contains such harmful salts, then will get dissolved when bricks come into contact with
water. When bricks contain such harmful salts as used exposed surface then serious surface
disruption occur which may harm outer plastering. This phenomenon is called efflorescence.
As per IS 3495 – 1992. To check the presence of efflorescence following procedure is adopted
1. Take a flat tray and fill it with a 2.5cm height of distilled water.
2. Treat five bricks as a test specimen and place these bricks vertically one after other. On
a tray containing distilled water. Now wait until the water is absorbed by bricks
3. Again fill the water up to same height 2.5cm and allow it to absorb water as above
(Second evaporation)
4. Now after second evaporation, examine the brick for efflorescence as below:
Description Extent of Deposits

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Description Extent of Deposits
Nil No perceptible deposit of efflorescence
Straight 10% area covered with a thin salts deposits.
Moderate Upto 50% area covered by heavy deposit.
No powdering or flaking
Heavy 50% or more area covered.
No powdering or flaking.
Serious Heavy Deposit
Powdering or flaking is observed
Brick is only used if the extent of efflorescence is from slight to moderate. The above-
mentioned tests are the simple and reliable test which gives an idea about the quality of bricks
on site.
6. Brick Earth:
The composition of Brick should be free from stones, kankare and other chemicals.
7. Soundness of Brick:
Take two bricks one in each hand and stuck it each other a good brick hears a metallic sound or
ringing sound. If brick breaks without sound, then it isn’t suitable for construction.
Throw the brick at the height of 1.5m to the ground. A good quality brick won’t break when it is
fallen from the 1.5m height.
8. Examine frog in brick:
Check the size of the frog and it should be 100mm x 40mm x 10mm. Any other lesser size of
frog leads to improper motor filling and requires more amount of mortar if the frog dimensions
are more than above which makes structure uneconomical.

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Due to scarcity of natural resources to manufacure bricks a new types of bricks are introduced
“AAC Bricks”
Defects in bricks
There can be many defects in bricks. Identifying defective bricks is important for the
consideration of stability and durability of load bearing brick masonry walls and structures.
Types of Defects in Bricks and their Identification
Following are the different types of defects generally found in bricks:
1. Over burning of bricks
When bricks over-burn, soft molten mass is produced and the brick will its shape along with
other designated requirements.

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Fig.1: over burnt bricks
2. Under burning of bricks
When bricks are not burnt to cause complete vitrification, the clay is not softened because of
insufficient heat and the pores are not closed.
Consequently, bricks with low compressive strength and high-water absorption will be
produced. They produce a dull sound when struck against each other.
Finally, such bricks are not recommended for construction works

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Fig.2: under burnt bricks
3. Bloating of bricks
Bloating of bricks is spongy swollen mass over the surface of burned bricks. Presence of excess
carbonaceous matter and Sulphur in brick-clay is the main cause of bloating.
Fig.3: bloating of bricks
4. Black core
Improper burning is the prime cause of brick black core. Bricks, which contains bituminous
matter or carbon and they are not completely removed by oxidation, will commonly experience
such problem.

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Fig.4: black core brick
5. Efflorescence
Presence of drying grey or white powder patches on the brick surface is the efflorescence
indicator. This defect is caused because of alkalis present in bricks. When bricks come in contact
with moisture, water is absorbed and the alkalis crystalize.
Lastly, efflorescence can be minimized by selecting proper clay materials for brick
manufacturing, preventing moisture to come in contact with the masonry, by providing
waterproof coping and by using water repellent materials in mortar and by providing damp
proof course.
Fig.5: efflorescence on bricks
6. Brick cracking
Straight cracks
Straight cracks at right angles from one of the long surfaces of the brick will develop.
Considerably rapid drying is the cause of straight cracks. Possibly, brick damage occurs even if
fired adequately.

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Fig.6: brick straight cracking on one of long surfaces
Random cracks
Cracks initiate arbitrarily on different brick surfaces.
Differential drying generate shrinkage. then, various lumps of dried materials will shrinkage
differently which eventually lead to random cracking.
additionally, the presence of pebbles in clay mix could lead to random cracking as well.
Fig.7: multiple brick surface cracking in random directions
7. Brick spalling
Irregular portion of the brick break away of fall off.
Heating of water inside brick is the cause of spalling

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Fig.8: Spalling of bricks
8. Chuffs
The deformation of the shape of bricks due to rain water falling on hot bricks is known as
chuffs.
9.Lime blowing
Disintegration of bricks is the indicator of lime blowing.
If bricks contain lime lump, then lime blowing is expected. The lime absorb water and expand
after its exposure to firing. Consequently, lime blowing will take place.
Bricks susceptible to lime blowing can be identified by submerging the brick in water. As a
result, the brick fractures and powdery lumps will be exposed.
Fig.9: Lime blowing defects
10. Spots
It is a dark spot on brick surface.
The presence of iron sulphide in clay brick is the main cause of spots.
Bricks with sports on its surface is unsuitable for exposed masonry work.

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Fig.10: spots in bricks
11. Lamination bricks
Thin lamina produces on the brick faces which weather out on exposure.
Entrapped air in the voids of clay is the cause of laminations.
Such bricks are weak in structure.

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Fig.11: Brick lamination
12. Defects in brick size
Oversize bricks
Brick oversize in width, length, and thickness
Fig.12: oversize brick in all dimensions
Size defects make bricks lighter than normal bricks
Oversize in all three dimensions of bricks might cause by under-firing, poor material selection
and preparation. For example, presence of too much sand that decline among of drying.
Oversize in width and length occur due to brick squashing while it is still wet. This may have
been occurred when the brick was set down on the ground or drying rack after being molded or
when a slop molded brick was pressed to flatten out a distortion.

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Fig.13: brick set on the ground cause oversize in length and width
Oversize in thickness, which is common problem in wire cut bricks, occurs during brick wire
cutting. the block of clay is forced through a row of wires. As a result, the force on the wire may
cause movement that changes the dimension of the opening which the clay passes through.
Fig.14: over sized bricks during wire cut process
Under-size bricks
This problem occurs due to several factors for example, faulty mould, presence of too much
clay in the batch, using too much water during the mixing stage, and over firing.
13. Defects in brick shape
Slump brick shape
It occurs when clay mix is considerably wet, so it slumps under its weight.

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Fig.15: Defects in brick shape; slump
Rounded corner brick
Corner breakage between drying and firing may cause this problem.
Another factor is that; the worker does not push clay into the mould properly.
Fig.16: defects in brick shape; round corner
Lip on bed face
Excessive clay is not removed from the face of the brick during manufacturing is the cause of
presence of lip on brick bed face.
Leaving flashing around brick top edge border during production process is another factor that
led to this issue.
Fig.17: Defects in brick shape, lip on top face
Banana brick shape

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It occurs when the brick is not turned around during initial drying phase prior to the hardening
of top face.
Fig.18: Defects in brick shape, banana shapes
Contaminated or distorted of brick under face
Surface on which bricks are dried is either uneven or dirty of combination thereof.
Frequently, it occurs with slope moulding as wetter mixture picks up more particles.
Fig.19: defects in brick shape, contaminated or distorted brick under face
Stacking marks on bricks
Bricks distort
Bricks get finger marks or other marks
Moving bricks from individual drying to stack drying before it is dried adequately is the cause of
stacking marks.

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Fig.20: defects in brick shape, stacking marks
Brick multiple distortions
It loses its shape and suffer different distortions at the same time.
Brick forming may be the cause of multiple distortions.
Lastly, brick over-burn at the base of the clamp cause multiple distortions as well.
Fig.21: defects in brick shape, multiple distortions
OR
Various defects in bricks
The various defects in bricks are explained as follows.
1. Over burning of bricks: - Burning of bricks should be done at temperature at which complete
vitrification occurs. If bricks are over burnt, a molten mass(soft) is produced and bricks lose
their shape. Such types of bricks are not used in construction.
2. Burning of bricks: - When bricks are burnt but complete vitrification does not occur. Then
such type of defect is known as under burning of bricks. Due to lesser amount of heat, the clay
is not softened and the pores are not closed. It leads to less compressive strength and higher
degree.

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3. Efflorescence: - Presence of alkalis in bricks causes this defects in bricks. When bricks come
in contact with moisture water is absorbed and the alkalis crystalise. Grey or white spots
appear on the surface of bricks after drying. This defect can be reduced by proper selection of
clay materials for manufacturing of bricks, preventing moisture to come in contact with the
masonary and by providing damp proof course.
4. Black core: - When brick clay contains bituminous matter or carbon and they are not
completely removed by oxidation, the brick converts in black core because of improper
burning.
5. Chuffs: - The deformation of the shape of bricks caused by the rain water falling on hot bricks
is chuffs.
6. Blisters: - Broken blisters are generally caused on the surface of sewer pipes and drain tiles
due to air imprisoned during their moulding.
7. Laminations: - These are caused by entrapped air in the voids of clay. Laminations produce
thin lamina on the brick faces, which weather out on exposure. Such bricks are weak in
structure.
Tests on Bricks
The following laboratory tests may be conducted on the bricks to find their suitability:
(i) Crushing strength
(ii) Absorption
(iii) Shape and size and
(iv) Efflorescence.
(i) Crushing Strength: The brick specimen is immersed in water for 24 hours. The frog of the
brick is filled flush with 1:3 cement mortar and the specimen is stored in damp jute bag for 24
hours and then immersed in clean water for 24 hours. The specimen is placed in compression
testing machine with 6 mm plywood on top and bottom of it to get uniform load on the
specimen. Then load is applied axially at a uniform rate of 14 N/mm2 . The crushing load is
noted. Then the crushing strength is the ratio of crushing load to the area of brick loaded.
Average of five specimen is taken as the crushing strength.
(ii) Absorption Test: Brick specimen are weighed dry. Then they are immersed in water for a
period of 24 hours. The specimen is taken out and wiped with cloth. The weight of each
specimen in wet condition is determined. The difference in weight indicate the water absorbed.
Then the percentage absorption is the ratio of water absorbed to dry weight multiplied by 100.
The average of five specimens is taken. This value should not exceed 20 per cent.
(iii) Shape and Size: Bricks should be of standard size and edges should be truely rectangular
with sharp edges. To check it, 20 bricks are selected at random and they are stacked along the
length, along the width and then along the height. For the standard bricks of size 190 mm × 90
mm × 90 mm. IS code permits the following limits:
Lengthwise: 3680 to 3920 mm
Widthwise: 1740 to 1860 mm
Heightwise: 1740 to 1860 mm.

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The following field tests help in acertaining the good quality bricks:
(i) uniformity in size
(ii) uniformity in colour
(iii) structure
(iv) hardness test
(v) sound test
(vi) strength test.
(i) Uniformity in Size: A good brick should have rectangular plane surface and uniform in size.
This check is made in the field by observation.
(ii) Uniformity in Colour: A good brick will be having uniform colour throughout. This
observation may be made before purchasing the brick.
(iii) Structure: A few bricks may be broken in the field and their cross-section observed. The
section should be homogeneous, compact and free from defects such as holes and lumps.
(iv) Sound Test: If two bricks are struck with each other they should produce clear ringing
sound. The sound should not be dull.
(v) Hardness Test: For this a simple field test is scratch the brick with nail. If no impression is
marked on the surface, the brick is sufficiently hard
(vi) Efflorescense: The presence of alkalies in brick is not desirable because they form patches
of gray powder by absorbing moisture. Hence to determine the presence of alkalies this test is
performed as explained below:
Place the brick specimen in a glass dish containing water to a depth of 25 mm in a well
ventilated room. After all the water is absorbed or evaporated again add water for a depth of
25 mm. After second evaporation observe the bricks for white/grey patches. The observation is
reported as ‘nil’, ‘slight’, ‘moderate’, ‘heavy’ or serious to mean
(a) Nil: No patches
(b) Slight: 10% of area covered with deposits
(c) Moderate: 10 to 50% area covered with deposit but unaccompanied by flaking of the
surface.
(d) Heavy: More than 50 per cent area covered with deposits but unaccompanied by flaking of
the surface.
(e) Serious: Heavy deposits of salt accompanied by flaking of the surface.
Chapter No 2
Aggregates:
It is defined as: “Aggregates are the inert materials that are mixed in fixed proportions with
a Binding Material to produce concrete “.
These act as fillers or volume increasing components on the one hand and are responsible for
the strength, hardness, and durability of the concrete on the other hand.

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Qualities of Aggregates.
Following are the most important qualities of an Aggregate.
1. It should be chemically inert, i.e., they should not react with cement or any other aggregate
or admixture.
2. It should possess sufficient hardness to resist scratching and abrasion in the hardened state.
3. It should possess sufficient toughness to bear impact and vibratory loads.
4. It should be strong enough to bear compressive and normal tensile loads in the ordinary
mixture.
5. It should be free from impurities, inorganic or organic in nature, which will affect adversely
on its quality.
6. It should be capable of producing an easily workable plastic mixture on combining with
cement and water.
Aggregate Classification | Types of Aggregates.
Aggregates are variously classified on the basis of their grain size, their origin, and their volume-
weight as follows:
(1.) Aggregate Types on the basis of Grain Size.
This is the most common classification, where in two types of aggregates are
distinguished: (Fine and Coarse).
(i) Fine Aggregates.
In the Fine Aggregates, the grain-size lies between 4.75 mm and 0.15 mm.
In other words, these pass-through from sieve with the mesh size of 4.75 mm and are retained
on a sieve of 0.15 mesh size. Sand is the most universally available natural Fine Aggregate.
(ii) Coarse Aggregates:

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Coarse aggregates are those that are retained on the sieve of mesh size 4.75 mm.
Their upper size is generally around 7.5 mm.
Gravels from river bed are the best coarse aggregates in the making of Common Concrete.
In those situations, if they are not easily available, Suitable rock types are crushed to the
desired particle sizes for making coarse aggregates.
(2.) Types on the Basis of origin.
There are three types on the Basis of Origin.
(i) Natural:
These include all those types of fine and coarse aggregates, that are available in almost ready to
use form, from natural resources.
Examples are sands from river beds, pits and beaches, and gravels from river banks.
(ii) Bye-product:
These include materials obtained as wastes from some industrial and metallurgical engineering
operations, which possess suitable properties for being used as aggregate.
Examples: Cinder obtained from burning of coal in locomotives and kilns.
And Slag is obtained from blast furnaces as Scum is the best example from this category.
(iii) Processed:
These form a special class in Aggregate. They are specifically manufactured for use in
making Quality Concretes.
Examples: They include burnt clay, Shales, vermiculite’s and perlite. They are
essential Ingredients of Lightweight Concrete.
(3.) Types on the Basis of Density.
Three types of aggregates are distinguished on the basis of their weight per unit volume.
(i) Standard or Normal:
These types of aggregates give strength and weighting to the Concrete of around 2300 to 2500
kg/m3.

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Gravels, Sand and Crushed stone, are all classed as Standard or Normal Aggregates.
(ii) High-Density Aggregates:
These are that type of Aggregates, which is used in standard proportions yield in heavy weight
concretes.
Such concretes are especially useful as shields against X-rays and radiations in the atomic
power plant.
Examples: Baryle – a natural mineral with a specific gravity of 4.3 is an example.
Concretes with such aggregate usually weight above 4000 kg/m3.
(iii) Light weight Aggregate:
They consist of natural and artificial materials of very low density so that the resulting concrete
is also quite Light in weight, generally with in a range of 350 to 750 kg/m3.
They are specially used in sound proofing and fire proofing constructions.
They are also used extensively in the manufacture of light weight Pre-Cast concrete blocks.
Physical Properties of Aggregete
Aggregate is the principle ingredient that is used in construction. The physical
properties of mineral aggregates are those that are used in reference to the physical
structure of particles that the aggregate consists of.
Absorption, Porosity and Permeability:
An important property of aggregates is the internal pore characteristics. What make up
this characteristicare the absorption, porosity and permeability of the aggregate. The size,
number and continuity of the pores has an effect on its strength, its resistance to
abrasion, texture of the surface, gravity, bonding capabilities as well as its resistance
to freezing and thawing. The ratio of the volume of the pores to the total volume of the particle
is what makes up the porosity. Absorption is the particle’s ability to absorb water. Permeability
is the particle’s ability to let water pass through it.
Texture of the Surface:
The pattern and the roughness or smoothness of the aggregate is the surface texture. It plays a
substantial role in creating a bond between the aggregate and the cementing material. For
example, when the surface of an aggregate has a rough texture, it gives the cementing
material something to grip and this produces a stronger bond. The texture of the surface also
plays a role in the workability of hot mix asphalt, how much asphalt is required for the hot mix
and the water requirements in cases where portland cement concrete is being used.
Strength and Elasticity:
The strength of an aggregate is measured in terms of its ability to endure forces that may push
or crushwhile it is being used. Elasticity refers to how much the particle can stretch. High levels

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of both these properties are required in the base and surface. The rate at which the concrete
disintegrates is minimized while the stability of the compacted material is maximized by these
properties.
Density and Specific Gravity:
The weight per unit of volume of a substance makes the density while specific gravity is the
ratio of the density of the substance to the density of water. The density and the specific gravity
of an aggregateparticle depend on the density and specific gravity of the minerals making up
the particle and also on how porous the particle is.
Voids in the Particles:
Voids are natural pores that are present in the aggregate particles. These pores are filled with
air and water. These voids affect the specific gravity as well as the absorption of
the aggregates. They may not be visible but most aggregates have pores. The voids that are
present between the particles have an effect on the design of hot mix asphalt or portland
cement concrete.
Hardness of the Minerals:
The resistance of the aggregate to abrasion and degradation is controlled by the hardness of
the minerals which the aggregate particles are made up of and the firmness with which the
grains of the particles are cemented or locked together. Minerals that have a low degree
of hardness compose soft aggregate particles. The weaker the particles are, the poorer the
cementation is.
Shape of the Particles:
The shape of the aggregate particles affects the workability and strength of both portland
cement concrete and hot asphalt mixes. It also has an effect on how much asphalt is needed for
the mix. Crushedstone or crushed gravel are considered to be the best types of aggregates to
use for strength. When crushed aggregates that have irregular or angular particles are used,
they interlock or bind closer when they are compacted or consolidated.
Crushed stone or gravel aggregates make the asphalt or concrete mix difficult to place. To make
them easier to work with, both angular and round particles are used in many mixes.
Aggregate Particle Coatings:
There is a layer that covers the entire or part of the surface of an aggregate which is known as
a coating. The coating may be natural, like mineral deposits that are formed in sand
or gravel by ground water. It could also be artificial like dust that is formed by crushing and
handling of the particles.

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Generally, it is required that aggregates are washed to remove the coating that is left on the
particles. This is necessary as the coating could prevent a good bond to form between
the aggregate surface and the cementing agent. The bonding agent that is required in
the mixture could also increase due to these coatings.
In the future, it is thought that aggregates will be supplied more from recycled or waste
materials. To make sure that there is no decrease in the quality and performance of the
products, the challenge will be to process and test these materials. The goal would be to make
sure that such materials have the fundamental chemical,
physical, and mechanical characteristics that guarantee high performance and workability.
Propertise of Good Sand
Good sand should be pure silica. It should be free from clay, salt, silt and organic matters. It is
better wash sand before construction work.
Sand is one of the important constituents of concrete. The main purpose of mixing sand (fine
aggregate) in concrete is to fill the voids between Coarse aggregate. And the voids between fine
aggregate is filled with cement. Sand bulks the concrete and helps to increase the workability of
concrete.
Sand is formed by the weathering of rocks. Well, different regions use the variety of sands (Pit
sand, River sand, Sea Sand) in construction according to the availability. A good fine aggregate
should be well graded (all particles that have almost same size).
The fine aggregate used for construction should pass 4.75mm sieve and retain on 150microns
sieve.
Below mentioned tests are the simple tests which you can perform quickly on site to find out
the quality of Sand. These tests include checking the properties of Sand which affect the
strength and the quality.
Tests for finding quality of sand on site: -

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Excessive clay / Silt:-
Presence of clay in Sand makes the sand cohesive, the good quality of sand should have less
percentage of clay in it.
Presence of excessive clay can be determined in two ways:-
1. For testing presence of clay in the sand, take a glassful of water and add some sand to it.
Shake it vigorously and allow the sand to settle. Check whether an apparent layer is
formed on the sand. A good quality of sand should have less than 8% of clay in it.
2. Hold some dry sand and drop it. If the Sand adheres to your palm, then it has Clay.
Presence of Organic Impurities in Sand: -
For detecting the presence of Organic impurities in fine aggregate. Take a Sample of sand and
add it in Sodium Hydroxide [NaOH] Solution, Stir the solution for few minutes, if the color of
solution changes to brown, then the sand has organic impurities which are not suitable for
construction. Good quality of sand shows lighter color when it is mixed with NaOH solution.
Presence of Excessive moisture content / Bulking of Sand: -
Presence of excessive moisture content in sand causes increase in the volume of sand. Fine
Aggregate Which contains more than 5% of moisture content in its volume is not suitable for
construction purposes.
For accurate conclusions, fineness modulus test and silt content by weight are suggested for
large projects
What is Bulking of Sand | Its Classification & How to Calculate it?
Sand is an important construction material of natural origin, mixed with cement and lime,
millions of tons of sands are used every month for construction as mortars, plasters, and
concrete.
The term sand is used for rock particles that range in grain size between 2 mm and 1/16 mm. In
composition, they are predominantly an oxide of silica SiO2.
Mineralogically, they consist mostly of broken grains of mineral Quartz (SiO2) produced as a
result of the breakdown of sandstones and similar rocks.
We will discuss below in details Classification and Bulking of Sand. So Let’s move on:
Classification of Sand.
Sands are classified variously on the basis of their mode of origin, their composition, and their
grain size.
Classification of Sands according to the mode of origin:
According to the mode of origin, sands are of three types, namely, pit sands, stream
sands and marine sands.

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The pit sands are generally sharp and angular in outline. Winds usually deposited them and
form accumulations in soils that may be covered by clays. These sands, when cleaned and
washed, make good mortars.
The river sands occur as accumulations of great extent along the base and banks of all the rivers
in plains and semi-hilly areas. The shape of the sand grains in river sands is almost round (due
to considerable transport in river waters).
These are generally free from clay, salt encrustations, and organic impurities. Hence, these are
the most commonly used sand for making mortars, plasters, and concrete.
The marine sands occur on beaches and along the seashores. Like river sands, they consist of
rounded grains of quartz. A common difficulty with these sands is that their grains are often
covered with coatings of salts from sea water.
These salts are not easily separable. Hence, if used in mortars or concrete, the salts react with
the binding materials creating a lot of difficulties. Moreover, the salt encrustations are often
hygroscopic, i.e., they absorb moisture from the atmosphere.
This also results in delayed setting, dampness and efflorescence may also occur in mortar
or concrete made with these sands. Hence, marine sands are considered of inferior quality and
should be better avoided. When these become the only source available, marine sands must be
thoroughly washed before use.
Classification of Sand according to its composition:
According to composition, following three categories of sand are recognized in engineering
fields.
Clean sands: These are well-graded sand containing entirely or mostly quartz (SiO2) particles in
a wide range of grain size.
Silty sands: These are poorly graded sands which have a considerable proportion of silt (particle
size between 0.625 to 0.075 mm) and other non-plastic fines.
Clayey Sands: These are poorly graded sands having a prominent clay fraction (particle size
below 1/256 mm) and also plastic fines.
Obviously, for use in making mortars, plasters, and concrete. Clean sands must only be used.
Sand is also obtained artificially by crushing natural quartzite rock to the required grain size.
Classification of Sand according to its grain size:
According to grain-size, sand is classified as coarse. medium and fine sand: 2 – 1 mm, 1 – 0.25
mm, 0.25-0.15 mm, respectively.
Bulking of Sand:
Bulking of sand is an important volumetric change that takes place in sands when they are
moist. Sands increase in volume, to the extent of 20-30 percent, when they contain moisture
between 2-8 percent.
This is because moisture in small proportions forms thin films around the sand grains.
Fine sands bulk greater than coarse sand. When the moisture content is increased beyond 8-10
percent, the bulking of sand effect almost disappears. In fact, sand grains settled in a water
tank will have the same volume as dry sand.

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The quality of sand is determined concerning its clay content, contamination with organic
impurities and its salt encrustations. Good quality sands should be free from all these
impurities.
It is established that volume of sand will be more when water is present in it even in small
quantities. In other words, two batches of sand, one dry and one moist, that may have the
same weight, will have different volumes. The volume of moist sand will be more than that of
dry sand.
This change (increase) in the volume of sands on getting moist is termed as bulking of sand.
Full knowledge of bulking of sand is necessary for a construction engineer because sand is
sometimes used for mortars, plasters, and concrete by volume.
All the mix designs denote the proportion of sand is essentially in the dry state.
As such if this fact is ignored and sand in wet condition is added to the cement or lime, the
resulting mortar will be containing a lesser amount of sand than the required amount.
Hence, a correction factor for bulking of sand has to be applied alter-determining the rate of
bulking for the sand to be used in mortar and concrete making.
As regards the rate of bulking of sand, it has been observed that it is related to two factors.
(i) percentage of moisture content in the sand.
(ii) Gram-Size of the sand particles.
Thus, bulking effect is maximum when moisture content in the sand is between 4-6 percent. As
the water-content increases, this effect goes on decreasing, becoming negligible at 15-20 per
cent moisture content.
Similarly, other things being same, the fine sands (particle size 0.25 to 0.15 mm) show higher
bulking rate as compared to the coarse sands (particle size around 2 mm).
Bulking may be to the extent of 40 percent of the original dry volume of sand in the fine and 15
percent in the case of coarse sands.

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How to Calculate Bulking of Sand?
A quick method to determine bulking of sand of given sample containing some moisture is as
follows:
(Step-1): Take a clean glass cylinder and fill it about 3/4 with the sand sample. Then, Note down
its volume. Let’s Say; it’s Volume = V1= is 30 cm3.
(Step-2): Now carefully take the sand out and place it on a glass plate. Fill the glass cylinder
with water to 3/4 of its volume.
(Step-3): Put the sand sample back into the glass cylinder very slowly, Stirring the water while
adding sand into it. This is essential to make all the sand grains settle fully in the cylinder.
Note down the new volume of sand sample Let it be V2.
(If V2 = V1, it means that the sand samples have retained to its original volume, i.e., it has shown
no bulking).
But Let’s say in another case V = 24 cm. Then bulking of sand sample will be: V1-V2/V1 x 100.
Now just put the values of V1 = 30 cm3 and V2 = 24 cm3.
So, Now 30-24/30 x 100 => 6/30 x 100 => 20%.
So, this means that 20% of bulking of sand has taken place.

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Test Procedure to Determine the Bulking of Sand
Following steps can be followed to calculate the percentage of bulking of sand in a given
sample-
1. Fill the measuring cylinder with the sample up to 200 ml mark.
2. For accurate measurement steel scale can be used, but no compaction of sand is
allowed.
3. The sand is to be transferred to a container.
4. The measuring cylinder is refilled with 100ml water.
5. The measuring cylinder should be refilled with sample sand and stirred with a steel rod.
6. Give some time so that the sand can settle.
7. The level of sand will be below the 200ml mark this time. Let the present level be “a.”
8. So the bulking of sand for this sample will be determined by the following equation-
BulkingofSand=200−aa×100BulkingofSand=200−aa×100
9. The procedure should be repeated twice and the average value of the tree observation
will be the percentage of bulking of sand for the given sample.
PROPERTIES AND TESTING OF AGGREGATES FOR PAVEMENT WORKS
Aggregates plays vital role in the construction of pavement. They have great capability of load
transfer to the Subgrade soil. Aggregates have different properties which are tested individually
with different types of tests for the construction of pavement.

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Aggregate should qualify all the tests conducted to give better results after construction. The
properties of aggregate and their respective tests are given below.
Properties and Tests of Aggregates for Pavement Works
Aggregate Property Test to be conducted
strength Crushing strength test
Hardness
Abrasion test
Impact value Impact test
Resistance against weathering Soundness Test
Shape of aggregate Shape test
Bitumen adhesion Bitumen Adhesion test

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Specific gravity Specific gravity test
Water absorption Water absorption test
Crushing Strength Test on Aggregates
Aggregate crushing value gives the Crushing strength of aggregate up to which it
can bear the load without fail. To conduct crushing strength test we need
compression testing machine, cylindrical measure, plunger and Isa sieves.
First sieve the sample aggregate, aggregate passing 12.5mm sieve and retaining
10mm sieve is oven dries at 100-110o
C for 3-4 hrs. The cylinder is filled with
aggregate in 3 layers, 25 strokes of tampering for each later. Note down its
weight and insert the plunger and placed it on compression testing machine.
Apply the load at uniform rate of 40 tonnes load in 10 minutes. Then stop the
machine and crushed aggregate is sieved through 2.36mm sieve and aggregate
passing 2.36mm sieve is weighed.
Aggregate crushing value can be obtained from below formula:
Aggregate crushing value = (W2/W1) *100 %

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Abrasion Test on Aggregates
Hardness property of aggregate is determined by conducting abrasion test. Los
Angeles abrasion testing machine is used to conduct this test.
For this test, the sample taken should be clean and dried. The sample is weighed
W1 and placed in Los Angeles testing machine and the machine is operated.
Machine should be rotated at a speed of 20-33 revolutions per minute. After 1000
revolutions the sample is taken out and sieved through 1.7mm sieve. Sample
retained on 1.7mm is washed and dried and note down its weight W2.
Aggregate abrasion value = {(W1-W2)/W2} x 100%
Impact Test on Aggregates
Impact value of aggregate will give aggregate capability against sudden loads or
forces. For this test also aggregate passing through 12.5mm and retained on
10mm sieve is taken and oven dried.
Fill the cylinder with aggregate in 3 layers, 25 strokes of tamping for each layer.
Weight w1 noted. The cylinder is placed in impact testing machine which consist
a hammer. After placing the cylinder, hammer is raised to 380mm and release
freely. Then it will blow the aggregates. Repeat it for 15 such blows. After that
take down the sample and aggregate passing through 2.36mm sieve is weighed
as w2.

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Aggregate impact value = (W2/W1) *100 %
Soundness Test on Aggregates
To determine the weathering resistance of aggregate soundness test is
conducted. If the resistance against weathering is good for aggregate, then it will
have high durability.
For soundness test we need some chemical solutions namely sodium sulphate or
magnesium sulphate. The sample of aggregate passing through 10mm sieve and
retained on 300 micron sieve is taken. Dry and weigh the sample and immerse
them in the chemical solution for about 18 hours. After that, Take the sample and
dried it in oven at 100 -110o
c. repeat this procedure 5 times for one sample, and
weigh the aggregate finally and note down the difference in weight loss.
The weight loss should be below 12% if sodium sulphate is used, below 18% if
magnesium sulphate is used.

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Shape test on Aggregates
Shape of aggregate is also important consideration for the construction of
pavement. Aggregate should not contain flaky and elongated particles in it. If
they contain this type of particles, they will affect the stability of mix.
The percentage by weight of aggregates whose least dimension is less the 3/5th
of its mean dimension is called as flakiness index. The percentage by weight of
aggregate particles whose greatest dimension is 1.8th times their mean
dimension is called as elongation index.
In this test shape test gauges are taken and minimum of 200 pieces containing
sample is passed through respective gauges. Material retained on Thickness
gauge and material retained on length gauge is weighed to an accuracy of 0.1%.

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Bitumen Adhesion test on Aggregates
Bitumen adhesion test will give the stripping of bitumen from the aggregate. In
case of bitumen pavement, the bitumen should be in pure contact with
aggregate. To attain this aggregate should be clean and dry.
To determine the stripping value of bitumen static immersion test is conducted on
aggregates. In this test the aggregates are coated with bitumen and dried. After
drying they are immersed in water at 40o
c for about 24 hours. Stripping value of
aggregate should not exceed 5%.

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Specific gravity test on Aggregates
Specific gravity of an aggregate is the ratio of its mass to that of an equal volume
of distilled water at specific temperature. The specific gravity of aggregate is of
two types. Bulk specific gravity, in which total volume of aggregates along with
their void space is considered. Apparent specific gravity, in which the volume of
aggregates without considering void spaces is taken into account.
Bulk specific gravity G = {dry weight of aggregate/total volume of aggregate}/
density of water
Apparent specific gravity G= {dry weight of aggregate/volume of aggregate without
void space}/ density of water
Water absorption test on Aggregates
This test helps to determine the water absorption value of aggregate. To perform
this test minimum 2 kg sample should be used. The sample should be cleaned
and dried. Place the sample in wire basket and dip the basket in distilled water
bath. To release the air between aggregates just lift and dip the basket for about
25 times in 25 seconds.

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Leave the basket for 24 hours and after that allowed it to drain for few minutes.
Aggregates should be taken on dry cloth and exposed them to atmosphere
sunlight. After drying, weigh the aggregates W1. Then place the aggregate in
oven at 100-110o
c for 24 hrs. After oven drying again weight the aggregate W2.
Water absorption of aggregates = {(W1-W2)/W2} x 100%
Chapter No 3
Concrete
Plain concrete, commonly known as concrete, is an intimate mixture of binding material, fine
aggregate, coarse aggregate and water. This can be easily moulded to desired shape and size
before it looses plasticity and hardens. Plain concrete is strong in compression but very weak in
tension. The tensile property is introduced in concrete by inducting different materials and this
attempt has given rise to RCC, RBC, PSC, FRC, cellular concrete and Ferro cement. In this
chapter proportioning, mixing, curing, properties, tests and uses of plain concrete is dealt in
detail. The other improved versions of concrete are explained and their special properties and
uses are pointed out.
Importance of Concrete.
We are actually living in the concrete age. It has become so important because it is used in
almost every type of construction like: (buildings, roads and highways, tunnels, storage dams
and power generating plants, airports and atomic power reactors).
Thus, in buildings, it is used almost from foundation to topmost storeys. In transportation, it is
used in Streets, Highways, Airports, etc.
Concrete is also a material used extensively for water storage and transport such as in the lining
of canals and water reservoirs.

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In addition to the above primary uses, It is also used as a coating material for specific purposes
such as for waterproofing, fireproofing, soundproofing and shielding against radiations in X-rays
plants and atomic power plants.
The essential property of concrete is that it sets and hardens into a strong, rock-like mass
within a short period.
The ultimate strength and other properties of concrete depend on a number of factors, like:
 The nature of aggregate materials used.
 The quality and proportions of cement, aggregates.
 Water used for making the mixture.
 And on the Workmanship.
The Composition is generally expressed in terms of relative volumes of:
 Cement.
 Fine aggregate (sand).
 And coarse aggregate (gravel etc.).
Thus a 1:2:4 concrete indicates a mix having 1 part by volume of cement, 2 parts of sand and 4
parts of gravel or crushed aggregates.
In actual mixing, the relative volumes are converted to weights of respective materials.
Concrete Ingredients.
Following are the ingredients of concrete.
1. Binding material (Cement or Lime).
2. Fine aggregate (Sand or such other materials).
3. Coarse aggregate (Gravel, Crushed stone or such other materials). And Water.
4. Admixtures are classed as optional ingredients.
Function of Binding Material.
The function of a Binding material (Cement or Lime) is to bind the coarse and fine
aggregate particles together.
Although “Portland Cement” is the most common binding material used as a binder in a
mixture. Much research has been done to prove that lime (especially Hydraulic Lime) can also
be used successfully as a Binding material in common type of construction.
Lime is economical as compared to cement, and also strong enough for the ordinary type of
construction.
Function of Aggregates.
The function of Fine aggregates serves the purpose of filling all the open spaces in between the
coarse particles. This way the porosity of the final mass is decreased.

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The maximum particle size in fine aggregates is always less than 6.35 mm. However, sand is
commonly and universally used as a fine aggregate, and its grain size is around 2 mm.
And the function of Coarse aggregates is to act as the main load-bearing component of
concrete.
When a good number of coarse aggregate fragments (all more than 6.35 mm in diameter) are
held together by a cementing material, their behavior towards the imposed loads is just like a
very strong rock mass.
Gravel and crushed stone are commonly used for this purpose.
Function of Water.
Water is the main component of the concrete mix. Water plays an important role in the process
of the chemical reaction of cement and aggregates.
Function of Admixtures.
Admixture affects the setting time of cement, and they are used mostly for specific purposes.
Different Types of Concrete.
A brief account of different types of concrete is given below.
1. Plain or Ordinary Concrete.
2. Lightweight Concrete.
3. High-Density Concrete.
4. Reinforced Concrete.
5. Precast Concrete.
6. Prestressed Concrete.
7. Air Entrained Concrete.
8. Glass Concrete.
9. Rapid hardening.
10. Asphalt.
11. Lime.
12. Roller compacted.
13. Stamped.
14. Pumped.
15. Vacuum.

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16. Permeable.
17. Shotcrete.
18. Ready-mix.
19. Self-Consolidated.
So Let’s start from the beginning.
1. Plain or Ordinary Concrete.
It is one of the most commonly used types of concrete. In this type of concrete, the essential
constituents are cement, sand and coarse aggregates designed and mixed with a specified
quantity of water.
The ratio of essential constituents may be varied within wide limits. A very commonly used mix
design, commonly known as Nominal Mix Design is 1:2:4.
Plain concrete is mostly used in the construction of pavements and in buildings, where very
high tensile strength is not required. It is also used in the construction of Dams.
Among the most important properties of ordinary concrete, the following may be mentioned.
 Density: 2200 – 2500 Kg/meter.cube.
 Compressive Strength: 200 – 500 Kg/centimeter.square.
 Tensile Strength: 50 – 100 Kg/centimeter.square.
 Durability: Very Satisfactory.
2. Lightweight Concrete:
Any types of concrete having a density less than 1920 Kg/m3 is classed as lightweight concrete.
Various types of aggregates that are used in the manufacturing of lightweight concrete include
natural materials like pumice and scoria, artificial materials like expanded shales and clays and
processed materials like perlite and vermiculite.
The single important property of lightweight concrete is its very low thermal conductivity.
For example: Thermal conductivity – the k value, for plain concrete may be as high as 10-12. But
the thermal conductivity of Lightweight concrete is about 0.3.
Lightweight Concretes are used, depending upon their composition, for thermal insulation, for
protecting steel structures, they are also used in long span bridge decks, and even as building
blocks.
Aerated Concrete is a variety of extremely lightweight concrete (density 480-800 Kg/m3 ). This
is obtained by using cement, sand and powdered fuel ash as constituents.
3. High Density Concrete:
This type of concrete is also called heavy weight concrete. In this concrete type, the density
varies between 3000-4000 Kg/m3.

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These types of concrete are prepared by using high density crushed rocks as coarse aggregates.
Among such materials, Barytes is the most commonly used material, which has a specific gravity
of 4.5. They are mostly used in atomic power plants and other similar structures. Because it
provides good protection from all type of radiations.
4. Reinforced Concrete:
It is also called RCC (Reinforced Cement Concrete). In this concrete type steel in various forms is
used as reinforcement to give very high tensile strength.
In fact, it is because of the combined action of plain concrete (having high compressive
strength) and steel (having high tensile strength).
The steel reinforcement is cast in the form of rods, bars, meshes and all conceivable shapes.
Every care is taken to ensure the maximum bond between the reinforcement and
the concrete during the setting and hardening process.
Thus, the resulting material (RCC) is capable of bearing all types of stress in any type of
construction. The RCC is the most important concrete type.
5. Precast Concrete:
This term refers to numerous types of concrete shapes that are cast into molds either in a
factory or at the site. However, they are not used in construction until they completely set and
hardened in a controlled condition.
Some of the examples of Precast Concrete are; precast poles, fence posts, concrete lintels,
staircase units, concrete blocks, and cast stones, etc.
These structural and decorative members are prepared in a well-equipped place where all
arrangements are made for;
1. Perfect proportioning of the ingredients of concrete.
2. Thorough mixing of the cement, aggregates, and water to obtain the mix of the desired
design and consistency.
3. Careful handling during transport and placement in the perfect design molds.
4. Perfect curing, under the controlled conditions of temperature and humidity. Even steam
curing is used to obtain precast products having high strength in much less time.
5. The latest trend in the construction industry is to shift more and more to prefabricated
concrete units in building construction.

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6. Prestressed Concrete:
It is a special type of reinforced concrete in which the reinforcement bars are tensioned before
being embedded in the concrete. Such tensioned wires are held firm at each end while the
concrete mix is placed. The result is that when concrete sets and hardens, the whole concrete
members, so the cast is put into compression.
This sort of arrangement makes the lower section of the reinforced concrete also stronger
against tension, which is the principal cause of the development of tension cracks in un-
tensioned reinforced concrete. Since pre-stressing involves the use of jacks and tensioning
equipment, the pre-stressed concrete is also cast in the factories.
Some of its advantages are the following.
1. The potential compressive strength of concrete gets considerably increased.
2. The risk of development of tension cracks in the lower sections of beams is considerably
reduced.
3. The resistance to shear is greatly reduced. This eliminates the necessity of stirrups to a great
extent.
4. Lighter members can be used than the un-tensioned (normal) reinforced-concrete.
5. The prestressed concrete is greatly favored in the construction of;
 Bridges.
 Long span Roofs.
 Most structures with the heavy dead load.
7. Air Entrained Concrete:

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It is a specially prepared plain concrete in which air is entrained in the form of thousands of
uniformly distributed particles.
The Volume of air thus, entrained may range between 3-6 percent of the concrete.
The air entrainment is achieved by adding a small quantity of foaming or gas-forming agents at
the mixing stage.
Fatty acids, fatty alcohols, and resins are some common air entraining agents.
Air entrained concrete is more resistant to;
 Scaling.
 Deterioration due to freezing and thawing.
 Abrasion.
8. Glass Concrete.
When the recycled glass is used as an aggregate in the concrete, this types of concrete is known
as Glass Concrete. They provide better thermal insulation and also have a great appealing look
as compared to other types.
9. Rapid Hardening Concrete.
This type of concrete is mostly used in under water construction and in repairing of roads.
Because its hardening time is very less. It can be hardened in just a few hours.
They are also used in building construction, where the work should be done fast.
10. Asphalt Concrete.
Asphalt concrete is a combination of aggregates and asphalt. It is also known as Asphalt. They
are vastly used in the highways, airports, as well as in the embankments.
They can be hardened in just an hour. That is the reason for its vast usage in roads.
11. Lime Concrete.
In this type of concrete, lime is used as a binding material with the aggregates. Before the
invention of cement, the mostly used concrete was lime concrete.
In today’s age, Lime concrete is also used in floors, domes, etc.
12. Roller Compacted Concrete.
This concrete is mostly used as a filling material. They don’t have a better strength value. They
are lean concrete and are compacted with the help of heavy means, like rollers.
Very less amount of cement is used in this type of concrete.
13. Stamped Concrete.
They are ordinary concrete with some little differences and are mostly used for architectural
purposes. A stamp of different shape and design placed on the concrete structures when they
are in their plastic state to acquire an appealing look design.
Pigments are used for color purposes of different types to give it more realistic and appealing
look.
14. Pumped Concrete.
Pumped concrete are used for high rise buildings. Where concrete conveyance other than the
pump is not an easy task almost an impossible task.

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They are made workable enough for an easy conveyance. Fines material are used for better
supply. The more, the finer material the easy will be the discharge.
The pump used for conveyance purposes are made from rigid or flexible materials to discharge
the concrete easily.
15. Vacuum Concrete.
In this types, more quantity of water is added to the concrete mix, and then the mixture is
poured into the form work.
The excess water is then removed from the concrete with the help of a vacuum pump. That is
why it is called the vacuum concrete.
This technique is used to attain the strength of concrete early. It will attain the compressive
strength within the period of 10 days as compared to 28 days of ordinary concrete.
16. Permeable Concrete.
Permeable concrete is prepared in such a manner that the water can be passed in it. They have
about 15 to 20 % voids so that the water can pass in it.
They are used in those areas where storm water issues persist.
17. Shotcrete.
Shotcrete is a concrete prepared in the same manner as ordinary, but the difference is that
they are placed differently.
They are placed with the help of higher air pressure through nozzles. The benefit of this
technique is that the compaction and placing of concrete will be done simultaneously.
18. Ready Mix Concrete.
This concrete type is prepared in concrete plants and or transported by the help of truck
mounted transit mixtures.
Once they are reached at the site then, there is no further treatment necessary.
The plant location will be at an adjustable location so that the concrete can be supplied before
the setting time ca be started.
19. Self Consolidated Concrete.
These types of concrete are compacted by its own weight, mean by the process of
consolidation. There is no need of using a vibrator or doing manual compaction.
The workability of concrete is always high in this type. That is the reason it is also known as
flowing concrete.
Preparing and Placing of Concrete
The following steps are involved in the concreting:
1. Batching
2. Mixing
3. Transporting and placing and
4. Compacting.
1. Batching: The measurement of materials for making concrete is known as batching. The

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following two methods of batching is practiced:
(a) Volume batching
(b) Weight batching.
(a) Volume Batching: In this method cement, sand and concrete are batched by volume. A
gauge box is made with wooden plates, its volume being equal to that of one bag of cement.
One bag of cement has volume of 35 litres. The required amount of sand and coarse aggregate
is added by measuring on to the gauge box. The quantity of water required for making concrete
is found after deciding water cement ratio. For example, if water cement ratio is 0.5, for one
bag of cement (50 kg), water required is 0.5 × 50 = 25 kg, which is equal to 25 litres. Suitable
measure is used to select required quantity of water. Volume batching is not ideal method of
batching. Wet sand has higher volume for the same weight of dry sand. It is called bulking of
sand. Hence it upsets the calculated volume required.
(b) Weight Batching: This is the recommended method of batching. A weighing platform is
used in the field to pick up correct proportion of sand and coarse aggregates. Large weigh
batching plants have automatic weighing equipments.
2. Mixing: To produce uniform and good concrete, it is necessary to mix cement, sand and
coarse aggregate, first in dry condition and then in wet condition after adding water.
The following methods are practiced:
(a) Hand Mixing
(b) Machine Mixing.
(a) Hand Mixing: Required amount of coarse aggregate for a batch is weighed and is spread on
an impervious platform. Then the sand required for the batch is spread over coarse aggregate.
They are mixed in dry condition by overturning the mix with shovels. Then the cement required
for the batch is spread over the dry mix and mixed by shovels. After uniform texture is observed
water is added gradually and mixing is continued. Full amount of water is added and mixing is
completed when uniform colour and consistancy is observed. The process of mixing is
completed in 6–8 minutes of adding water. This method of mixing is not very good but for small
works it is commonly adopted.
(b) Machine Mixing: In large and important works machine mixing is preferred. Figure 3.2
shows a typical concrete mixer. Required quantities if sand and coarse aggregates are placed in
the drum of the mixer. 4 to 5 rotations are made for dry mixing and then required quantity of
cement is added and dry mixing is made with another 4 to 5 rotations. Water is gradually added
and drum is rotated for 2 to 3 minutes during which period it makes about 50 rotations. At this
stage uniform and homogeneous mix is obtained.

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3. Transporting and Placing of Concrete. After mixing concrete should be transported to
the final position. In small works it is transported in iron pans from hand to hand of a set of
workers. Wheel barrow and hand carts also may be employed. In large scale concreting chutes
and belt conveyors or pipes with pumps are employed. In transporting care should be taken to
see that seggregation of aggregate from matrix of cement do not take place.
Concrete is placed on form works. The form works should be cleaned and properly oiled. If
concrete is to be placed for foundation, the soil bed should be compacted well and is made free
from loose soil.
Concrete should be dropped on its final position as closely as possible. If it is dropped from a
height, the coarse aggregates fall early and then mortar matrix. This segregation results into
weaker concrete.
4. Compaction of Concrete: In the process of placing concrete, air is entrapped. The
entrapped
air reduces the strength of concrete up to 30%. Hence it is necessary to remove this entrapped
air. This is achieved by compacting the concrete after placing it in its final position. Compaction
can be carried out either by hand or with the help of vibrators.
(a) Hand Compaction: In this method concrete is compacted by ramming, tamping, spading or
by slicing with tools. In intricate portions a pointed steel rod of 16 mm diameter and about a
metre long is used for poking the concrete.
(b) Compaction by Vibrators: Concrete can be compacted by using high frequency vibrators.
Vibration reduces the friction between the particles and set the motion of particles. As a result,
entrapped air is removed and the concrete is compacted. The use of vibrators reduces the
compaction time. When vibrators are used for compaction, water cement ratio can be less,

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which also help in improving the strength of concrete. Vibration should be stopped as soon as
cement paste is seen on the surface of concrete. Over vibration is not good for the concrete.
The following types of vibrators are commonly used in concreting:
(a) Needle or immersion vibrators
(b) Surface vibrators
(c) Form or shutter vibrators
(d) Vibrating tables.
Needle vibrators are used in concreting beams and columns. Surface vibrators and form
vibrators are useful in concreting slabs. Vibrating tables are useful in preparing precast concrete
elements.
Curing of Concrete
Curing may be defined as the process of maintaining satisfactory moisture and temperature
conditions for freshly placed concrete for some specified time for proper hardening of concrete.
Curing in the early ages of concrete is more important. Curing for 14 days is very important.
Better to continue it for 7 to 14 days more. If curing is not done properly, the strength of
concrete reduces. Cracks develop due shrinkage. The durability of concrete structure reduces.
The following curing methods are employed:
(a) Spraying of water
(b) Covering the surface with wet gunny bags, straw etc.
(c) Ponding
(d) Steam curing and
(e) Application of curing compounds.
(a) Spraying of water: Walls, columns, plastered surfaces are cured by sprinkling water.
(b) Wet covering the surface: Columns and other vertical surfaces may be cured by covering
the surfaces with wet gunny bags or straw.
(c) Ponding: The horizontal surfaces like slab and floors are cured by stagnating the water to a
height of 25 to 50 mm by providing temporary small hunds with mortar.
(d) Steam curing: In the manufacture of pre-fabricated concrete units steam is passed over the
units kept in closed chambers. It accelerates curing process, resulting into the reduction of
curing period.
(e) Application of curing compounds: Compounds like calcium chloride may be applied on
the curing surface. The compound shows affinity to the moisture and retains it on the surface.
It keeps the concrete surface wet for a long time.
Properties of Concrete
Concrete has completely different properties when it is the plastic stage and when hardened.
Concrete in the plastic stage is also known as green concrete. The properties of green concrete
include:
1. Workability
2. Segregation

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3. Bleeding
4. Harshness.
The properties of hardened concrete are:
1. Strength
2. Resistance to wear
3. Dimensional changes
4. Durability
5. Impermeability.
Properties of Green Concrete
1. Workability: This is defined as the ease with which concrete can be compacted fully without
seggregating and bleeding. It can also be defined as the amount of internal work required to
fully compact the concrete to optimum density. The workability depends upon the quantity of
water, grading, shape and the percentage of the aggregates present in the concrete.
Workability is measured by
(a) The slump observed when the frustum of the standard cone filled with concrete is lifted and
removed.
(b) The compaction factor determined after allowing the concrete to fall through the
compaction testing machine.
(c) The time taken in seconds for the shape of the concrete to change from cone to cylinder
when tested in Vee-Bee consistometer.
The suggested values of workability for different works are as shown in Table 3.2.
Table 3.2. Suggested values of workability
Application Slump
Compaction
Factor
Time in
Vee-Bee
1. Concreting of shallow sections with
vibrations
— 0.75 – 0.80 10 – 20
2. Concreting of light reinforced sections
with vibrators
— 0.80 – 0.85 5 – 10
3. Concreting of lightly reinforced sections
without vibrations and heavily reinforced
sections with vibrations
25 – 75 mm 0.85 – 0.92 2 – 5
4. Concreting of heavily reinforced sections
without vibration
75 – 125 mm More than 0.92 —
2. Segregation: Separation of coarse particles from the green concrete is called segregation.
This may happen due to lack of sufficient quantity of finer particles in concrete or due to
throwing of the concrete from greater heights at the time of placing the concrete. Because of
the segregation, the cohesiveness of the concrete is lost and honey combing results. Ultimately
it results in the loss of strength of hardened concrete. Hence utmost care is to be taken to avoid
segregation.
3. Bleeding: This refers to the appearance of the water along with cement particles on the

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surface of the freshly laid concrete. This happens when there is excessive quantity of water in
the mix or due to excessive compaction. Bleeding causes the formation of pores and renders
the concrete weak. Bleeding can be avoided by suitably controlling the quantity of water in the
concrete and by using finer grading of aggregates.
4. Harshness: Harshness is the resistance offered by concrete to its surface finish. Harshness
is due to presence of lesser quantity of fine aggregates, lesser cement mortar and due to use of
poorely graded aggregates. It may result due to insufficient quantity of water also. With harsh
concrete it is difficult to get a smooth surface finish and concrete becomes porous.
Properties of Hardened Concrete
1. Strength: The characteristic strength of concrete is defined as the compressive strength of
150 mm size cubes after 28 days of curing below which not more than 5 per cent of the test
results are expected to fail. The unit of stress used is N/mm2. IS 456 grades the concrete based
on its characteristic strength as shown in Table 3.3.
Table 3.3. Grades of concrete
Grade
M
10
M15 M20 M25 M30 M35 M40
Characteristic strength in M
N/mm2
10 15 20 25 30 35 40
Till year 2000, M15 concrete was permitted to be used for reinforced concrete works. But IS
456–2000 specifies minimum grade of M20 to be used for reinforced concrete works.
Strength of concrete depends upon the amount of cement content, quality and grading of
aggregates, water cement ratio, compaction and curing. Strength of concrete is gained in the
initial stages. In 7 days the strength gained is as much as 60 to 65 per cent of 28 days’ strength.
It is customary to assume the 28 days’ strength as the full strength of concrete. However
concrete gains strength after 28 days also. The characteristic strength may be increased by the
as factor given in Table 3.4.
Table 3.4. Effect of age factor on strength of concrete
Minimum age of member when
design load
is expected.
1 month 3 months 6 months
12
months
Age factor 1.0 1.10 1.15 1.20
The tensile strength may be estimated from the formula ft = 0.7 fck N/mm2, where fck is the
characteristic compressive stress. The modulus of elasticity may be estimated from the formula:
E = 50 fck N/mm2.
2. Dimensional Change: Concrete shrinks with age. The total shrinkage depends upon the
constituents of concrete, size of the member and the environmental conditions. Total shrinkage
is approximately 0.0003 of original dimension.
The permanent dimension change due to loading over a long period is termed as creep. Its
value depends upon the stress in concrete, the age of the concrete at the time of loading and
the duration of the loading. The ultimate creep strain may be estimated from the values of

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creep coefficient. The creep coefficient is defined as ultimate creep strain divided by the elastic
strain at the age of loading. These values are listed in Table 3.5.
Table 3.5. Creep coefficient based on the age of loading
Age of Loading 7 days 28 days 1 year
Creep Coefficient 2.2 1.6 1.1
The size of concrete may change due to thermal expansion also. The coefficient of thermal
expansion depends upon the nature of cement, the type of aggregates, cement content,
relative humidity and the size of the sections of the structural elements. Table 3.6 shows the
coefficient of thermal expansion of concrete with different types of aggregates.
Table 3.6. Coefficient of thermal expansion
Type of Aggregate Coefficient of Thermal Expansion/C°
1. Quartzite
2. Sand stone
3. Granite
4. Basalt
(1.2 to 1.3) × 10– 5
(0.9 to 1.2) × 10– 5
(0.7 to 0.95) × 10– 5
(0.8 to 0.95) × 10– 5
3. Durability: Environmental forces such as weathering, chemical attack, heat, freezing and
thawing try to destroy concrete. The period of existance of concrete without getting adversely
affected by these forces is known as durability. Generally dense and strong concretes have
better durability. The cube crushing strength alone is not a reliable guide to the durability.
Concrete should have an adequate cement content and should have low water cement ratio.
4. Impermeability: This is the resistance of concrete to the flow of water through its pores.
Excess water during concreting leaves a large number of continuous pores leading to the
permeability. Since the permeability reduces the durability of concrete, it should be kept very
low by using low water cement ratio, dense and well graded aggregates, good compaction and
continuous curing at low temperature conditions. The cement content used should be sufficient
to provide adequate workability with low water cement ratio and the available compaction
method.
Tests on Concrete
The following are some of the important tests conducted on concrete:
1. Slump test.
2. Compaction factor test.
3. Crushing strength test.
1. Slump Test: This test is conducted to determine the workability of concrete. It needs a
slump cone for test (Fig. 3.3). Slump cone is a vessel in the shape of a frustum of a cone with
diameter at bottom 200 mm and 50 mm at top and 300 mm high. This cone is kept over an
impervious platform and is filled with concrete in four layers. Each layer is tamped with a 16
mm pointed rod for 25 times. After filling completely, the cone is gently pulled up. The decrease
in the height of the concrete is called slump. Higher the slump, more workable is the concrete.
The desired values of slumps for various works have been shown in Table 3.2.

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2. Compaction Factor Test: This is another test to identify the workability of concrete. This
test is conducted in the laboratory. The test equipment consists of two hoppers and a cylinder
fixed to a stand, the dimensions and the distances between the three vessels being
standardized. Vessel A and B are having hinged bottoms whereas cylinder C is having fixed
bottom. [Ref. Fig. 3.4] Top vessel A is filled with the concrete to be tested. As soon as it is filled,
the hinged door is opened. Concrete is collected in vessel B. Then the hinged door of B is
opened to collect concrete in cylinder C. The concrete in cylinder C is weighted. Let it be W1.
Now cylinder is again filled with the sample of concrete in 50 mm layers, which is compacted by
ramming and vibrating. Then the weight of compacted concrete is determined. Let this weight
be W2. The ratio W1/W2 is termed as compaction factor. The specified values of compaction
factor for different works are already listed in Table 3.2.

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3. Crushing Strength Test: Metallic moulds of size 150 mm × 150 mm × 150 mm are used
for casting concrete cubes. Before filling mould, it is properly oiled on its inner surfaces, so that
cubes can be easily separated. Fresh cube is filled with concrete to be tested in 3 layers and
kept in the room. After 24 hours, cube is removed from the mould and kept under water for
curing. After 28 days of curing cubes are tested in the compression testing machine. In this test
cubes are placed over the smooth surface which is in contact with side plates of mould. The
crushing load is noted and crushing strength is found as load divided by surface area (150 × 150
mm2). Code specify the desirable strength of concrete for 3 days and 7 days for quick
assessment of strength of concrete.
Desirable Properties of Concrete
Appropriate quality and quantity of cement, fine aggregate, coarse aggregate and water should
be used so that the green concrete has the following properties:
(a) Desired workability
(b) No seggregation in transporting and placing
(c) No bleeding and
(d) No harshness.
Hardened concrete should have
(a) required characteristic strength
(b) minimum dimensional changes

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(c) good durability
(d) impermeable
(e) good resistance to wear and tear.
Uses of Concrete
1. As bed concrete below column footings, wall footings, on wall at supports to beams
2. As sill concrete
3. Over the parapet walls as coping concrete
4. For flagging the area around buildings
5. For pavements
6. For making building blocks.
However major use of concrete is as a major ingradient of reinforced and prestressed concrete.
Many structural elements like footings, columns, beams, chejjas, lintels, roofs are made with
R.C.C. Cement concrete is used for making storage structures like water tanks, bins, silos,
bunkers etc. Bridges, dams, retaining walls are R.C.C. structures in which concrete is the major
ingradient.
Chapter No 4
Cement
Cement is a commonly used binding material in the construction. The cement is obtained by
burning a mixture of calcarious (calcium) and argillaceous (clay) material at a very high
temperature and then grinding the clinker so produced to a fine powder. It was first produced
by a mason Joseph Aspdin in England in 1924. He patented it as portland cement.
Types of Cement
In addition to ordinary portland cement there are many varieties of cement. Important varieties
are briefly explained below:
(i) White Cement: The cement when made free from colouring oxides of iron, maganese and
chlorium results into white cement. In the manufacture of this cement, the oil fuel is used
instead of coal for burning. White cement is used for the floor finishes, plastering, ornamental
works etc. In swimming pools white cement is used to replace glazed tiles. It is used for fixing
marbles and glazed tiles.
(ii) Coloured Cement: The cements of desired colours are produced by intimately mixing
pigments with ordinary cement. The chlorium oxide gives green colour. Cobalt produce blue
colour. Iron oxide with different proportion produce brown, red or yellow colour. Addition of
manganese dioxide gives black or brown coloured cement. These cements are used for giving
finishing touches to floors, walls, window sills, roofs etc.
(iii) Quick Setting Cement: Quick setting cement is produced by reducing the percentage of
gypsum and adding a small amount of aluminium sulphate during the manufacture of cement.
Finer grinding also adds to quick setting property. This cement starts setting within 5 minutes
after adding water and becomes hard mass within 30 minutes. This cement is used to lay

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concrete under static or slowly running water.
(iv) Rapid Hardening Cement: This cement can be produced by increasing lime content and
burning at high temperature while manufacturing cement. Grinding to very fine is also
necessary. Though the initial and final setting time of this cement is the same as that of
portland cement, it gains strength in early days. This property helps in earlier removal of form
works and speed in construction activity.
(v) Low Heat Cement: In mass concrete works like construction of dams, heat produced due to
hydration of cement will not get dispersed easily. This may give rise to cracks. Hence in such
constructions it is preferable to use low heat cement. This cement contains low percentage
(5%) of tricalcium aluminate (C3A) and higher percentage (46%) of dicalcium silicate (C2S).
(vi) Pozzulana Cement: Pozzulana is a volcanic power found in Italy. It can be processed from
shales and certain types of clay also. In this cement pozzulana material is 10 to 30 per cent. It
can resist action of sulphate. It releases less heat during setting. It imparts higher degree of
water tightness. Its tensile strength is high but compressive strength is low. It is used for mass
concrete works. It is also used in sewage line works.
(vii) Expanding Cement: This cement expands as it sets. This property is achieved by adding
expanding medium like sulpho aluminate and a stabilizing agent to ordinary cement. This is
used for filling the cracks in concrete structures.
(viii) High Alumina Cement: It is manufactured by calcining a mixture of lime and bauxite. It is
more resistant to sulphate and acid attack. It develops almost full strength within 24 hours of
adding water. It is used for under water works.
(ix) Blast Furnace Cement: In the manufacture of pig iron, slag comes out as a waste product.
By grinding clinkers of cement with about 60 to 65 per cent of slag, this cement is produced.
The properties of this cement are more or less same as ordinary cement, but it is cheap, since it
utilise waste product. This cement is durable but it gains the strength slowly and hence needs
longer period of curing.
(x) Acid Resistant Cement: This cement is produced by adding acid resistant aggregated such
as quartz, quartzite, sodium silicate or soluble glass. This cement has good resistance to action
of acid and water. It is commonly used in the construction of chemical factories.
(xi) Sulphate Resistant Cement: By keeping the percentage of tricalcium aluminate C3A below
five per cent in ordinary cement this cement is produced. It is used in the construction of
structures which are likely to be damaged by alkaline conditions. Examples of such structures
are canals, culverts etc.
(xii) Fly Ash Blended Cement: Fly ash is a byproduct in thermal stations. The particles of fly ash
are very minute and they fly in the air, creating air pollution problems. Thermal power stations
have to spend lot of money to arrest fly ash and dispose safely. It is found that one of the best
way to dispose fly ash is to mix it with cement in controlled condition and derive some of the
beneficiary effects on cement. Now-a-days cement factories produce the fly ash in their own
thermal stations or borrow it from other thermal stations and further process it to make it
suitable to blend with cement. 20 to 30% fly ash is used for blending.

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Fly ash blended cements have superior quality of resistance to weathering action. The ultimate
strength gained is the same as that with ordinary portland cement. However, strength gained in
the initial stage is slow. Birla plus, Birla star, A.C.C. Suraksha are some of the brand mame of
blended cement.
Properties of Ordinary Portland Cement
(i) Chemical properties: Portland cement consists of the following chemical compounds:
(a) Tricalcium silicate 3 CaO.SiO2 (C3S) 40%
(b) Dicalcium silicate 2CaO.SiO2 (C2S) 30%
(c) Tricalcium aluminate 3CaO.Al2O3 (C3A) 11%
(d) Tetracalcium aluminate 4CaO.Al2O3.Fe2O3 (C3AF) 11%
There may be small quantities of impurifies present such as calcium oxide (CaO) and
magnesium oxide (MgO). When water is added to cement, C3A is the first to react and cause
initial set. It generates great amount of heat. C 3S hydrates early and develops strength in the
first 28 days. It also generates heat. C2S is the next to hydrate. It hydrates slowly and is
responsible for increase in ultimate strength. C4AF is comparatively inactive compound.
(ii) Physical properties: The following physical properties should be checked before selecting
a portland cement for the civil engineering works. IS 269–1967 specifies the method of testing
and prescribes the limits:
(a) Fineness (b) Setting time
(c) Soundness (d) Crushing strength.
(a) Fineness: It is measured in terms of percentage of weight retained after sieving the cement
through 90 micron sieve or by surface area of cement in square centimeters per gramme of
cement. According to IS code specification weight retained on the sieve should not be more
than 10 per cent. In terms of specific surface should not be less than 2250 cm2/gm.
(b) Setting time: A period of 30 minutes as minimum setting time for initial setting and a
maximum period of 600 minutes as maximum setting time is specified by IS code, provided the
tests are conducted as per the procedure prescribed by IS 269-1967.
(c) Soundness: Once the concrete has hardened it is necessary to ensure that no volumetric
changes takes place. The cement is said to be unsound, if it exhibits volumetric instability after
hardening. IS code recommending test with Le Chatelier mould for testing this property. At the
end of the test, the indicator of Le Chatelier mould should not expand by more than 10 mm.
(d) Crushing strength: For this mortar cubes are made with standard sand and tested in
compression testing machine as per the specification of IS code. The minimum strength
specified is 16 N/mm2 after 3 days and 22 N/mm2 after 7 days of curing. 1.4.3 Physical Tests on
Cement.
(a) Soundness Test: It is conducted by sieve analysis. 100 gms of cement is taken and sieved
through IS sieve No. 9 for fifteen minutes. Residue on the sieve is weighed. This should not
exceed 10 per cent by weight of sample taken.
(b) Setting Time: Initial setting time and final setting time are the two important physical

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properties of cement. Initial setting time is the time taken by the cement from adding of water
to the starting of losing its plasticity. Final setting time is the time lapsed from adding of the
water to complete loss of plasticity. Vicat apparatus is used for finding the setting times [Ref.
Fig. 1.5]. Vicat apparatus consists of a movable rod to which any one of the three needles
shown in figure can be attached. An indicator is attached to the movable rod. A vicat mould is
associated with this apparatus which is in the form of split cylinder.
Before finding initial and final setting time it is necessary to determine water to be added to get
standard consistency. For this 300 gms of cement is mixed with about 30% water and cement
paste prepared is filled in the mould which rests on non porous plate. The plunger is attached
to the movable rod of vicat apparatus and gently lowered to touch the paste in the mould. Then
the plunger is allowed to move freely. If the penetration is 5 mm to 7 mm from the bottom of
the mould, then cement is having standard consistency. If not, experiment is repeated with
different proportion of water fill water required for standard consistency is found. Then the
tests for initial and final setting times can be carried out as explained below:
Initial Setting Time: 300 gms of cement is thoroughly mixed with 0.85 times the water for
standard consistency and vicat mould is completely filled and top surface is levelled. 1 mm
square needle is fixed to the rod and gently placed over the paste. Then it is freely allowed to
penetrate. In the beginning the needle penetrates the paste completely. As time lapses the
paste start losing its plasticity and offers resistance to penetration. When needle can penetrate
up to 5 to 7 mm above bottom of the paste experiment is stopped and time lapsed between
the addition of water and end if the experiment is noted as initial setting time.

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Final Setting Time. The square needle is replaced with annular collar. Experiment is continued
by allowing this needle to freely move after gently touching the surface of the paste. Time
lapsed between the addition of water and the mark of needle but not of annular ring is found
on the paste. This time is noted as final setting time.
(c) Soundness Test: This test is conducted to find free lime in cement, which is not desirable. Le
Chatelier apparatus shown in Fig. 1.6 is used for conducting this test. It consists of a split brass
mould of diameter 30 mm and height 30 mm. On either side of the split, there are two
indicators, with pointed ends. The ends of indicators are 165 mm from the centre of the mould.
Properly oiled Le Chatelier mould is placed on a glass plate and is filled completely with a
cement paste having 0.78 times the water required for standard consistency. It is then covered
with another glass plate and a small weight is placed over it. Then the whole assembly is kept
under water for 24 hours. The temperature of water should be between 24°C and 50°C. Note
the distance between the indicator. Then place the mould again in the water and heat the
assembly such that water reaches the boiling point in 30 minutes. Boil the water for one hour.
The mould is removed from water and allowed to cool. The distance between the two pointers
is measured. The difference between the two readings indicate the expansion of the cement
due to the presence of unburnt lime. This value should not exceed 10 mm.
(d) Crushing Strength Test: For this 200 gm of cement is mixed with 600 gm of standard sand
confirming to IS 650–1966. After mixing thoroughly in dry condition for a minute distilled
potable water
𝑃
4
+ 3 percentage is added where P is the water required for the standard
consistency. They are mixed with trowel for 3 to 4 minutes to get uniform mixture. The mix is
placed in a cube mould of 70.6 mm size (Area 5000 mm2) kept on a steel plate and prodded
with 25 mm standard steel rod 20 times within 8 seconds. Then the mould is placed on a
standard vibrating table that vibrates at a speed of 12000 ± 400 vibration per minute. A hopper
is secured at the top and the remaining mortar is filled. The mould is vibrated for two minutes

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and hopper removed. The top is finished with a knife or with a trowel and levelled. After 24 ± 1
hour mould is removed and cube is placed under clean water for curing.
After specified period cubes are tested in compression testing machine, keeping the specimen
on its level edges. Average of three cubes is reported as crushing strength. The compressive
strength at the end of 3 days should not be less than 11.5 N/mm2 and that at the end of 7 days
not less than 17.5 N/mm2.
Cement Manufacturing Process
Stage of Cement Manufacture
There are six main stages of cement manufacturing process.
Stage 1
Raw Material Extraction/Quarry
The raw cement ingredients needed for cement production are limestone (calcium), sand and
clay (silicon, aluminum, iron), shale, fly ash, mill scale and bauxite. The ore rocks are quarried
and crushed to smaller pieces of about 6 inches. Secondary crushers or hammer mills then
reduce them to even smaller size of 3 inches. After that, the ingredients are prepared for
pyroprocessing.
Stage 2
Grinding, Proportioning and Blending
The crushed raw ingredients are made ready for the cement making process in the kiln by
combining them with additives and grinding them to ensure a fine homogenous mixture.
The composition of cement is proportioned here depending on the desired properties of the
cement. Generally, limestone is 80% and remaining 20% is the clay. In the cement plant, the
raw mix is dried (moisture content reduced to less than 1%); heavy wheel type rollers and
rotating tables blend the raw mix and then the roller crushes it to a fine powder to be stored in
silos and fed to the kiln.
Stage 3
Pre-Heating Raw Material
A pre-heating chamber consists of a series of cyclones that utilizes the hot gases produced from
the kiln in order to reduce energy consumption and make the cement making process more
environment-friendly. The raw materials are passed through here and turned into oxides to be
burned in the kiln.
Stage 4
Kiln Phase
The kiln phase is the principal stage of the cement production process. Here, clinker is produced
from the raw mix through a series of chemical reactions between calcium and silicon dioxide
compounds. Though the process is complex, the events of the clinker production can be written
in the following sequence:
1. Evaporation of free water

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2. Evolution of combined water in the argillaceous components
3. Calcination of the calcium carbonate (CaCO3) to calcium oxide (CaO)
4. Reaction of CaO with silica to form dicalcium silicate
5. Reaction of CaO with the aluminum and iron-bearing constituents to form the liquid
phase
6. Formation of the clinker nodules
7. Evaporation of volatile constituents (e. g., sodium, potassium, chlorides, and sulfates)
8. Reaction of excess CaO with dicalcium silicate to form tricalcium silicate
The above events can be condensed into four major stages based on the change of
temperature inside the kiln:
1. 100°C (212°F): Evaporation of free water
2. 100°C (212°F)-430°C (800°F): Dehydration and formation of oxides of silicon, aluminum,
and iron
3. 900°C (1650°F)-982°C (1800°F): CO2 is evolved and CaO is produced through calcination
4. 1510°C (2750°F): Cement clinker is formed
The kiln is angled by 3 degrees to the horizontal to allow the material to pass through it, over a
period of 20 to 30 minutes. By the time the raw-mix reaches the lower part of the kiln, clinker
forms and comes out of the kiln in marble-sized nodules.
Stage 5
Cooling and final grinding
After exiting the kiln, the clinker is rapidly cooled down from 2000°C to 100°C-200°C by passing
air over it. At this stage, different additives are combined with the clinker to be ground in order
to produce the final product, cement. Gypsum, added to and ground with clinker, regulates the
setting time and gives the most important property of cement, compressive strength. It also
prevents agglomeration and coating of the powder at the surface of balls and mill wall. Some
organic substances, such as Triethanolamine (used at 0.1 wt.%), are added as grinding aids to
avoid powder agglomeration. Other additives sometimes used are ethylene glycol, oleic acid
and dodecyl-benzene sulphonate.
The heat produced by the clinker is circulated back to the kiln to save energy. The last stage of
making cement is the final grinding process. In the cement plant, there are rotating drums
fitted with steel balls. Clinker, after being cooled, is transferred to these rotating drums and
ground into such a fine powder that each pound of it contains 150 billion grains. This powder is
the final product, cement.
Stage 6
Packing and Shipping
Cement is conveyed from grinding mills to silos (large storage tanks) where it is packed in 20-40
kg bags. Most of the product is shipped in bulk quantities by trucks, trains or ships, and only a
small amount is packed for customers who need small quantities.
Chemical Reactions during Cement Manufacturing Process

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The reactions that take place (after evaporation of free water) between the reactants in the kiln
phase of cement making process are as follows:
Clay Decomposition:
Si2Al2O5(OH)2 → 2 SiO2 + Al2O3 + 2 H2O (vapor)
KAlSi3O8 (orthoclase) + 0.5 SO2 + 0.25 O2 → 3 SiO2 + 0.5 Al2O3 + 0.5 K2SO4
Dolomite Decomposition:
CaMg(CO3)2 → CaCO3 + MgO + CO2
KMg3AlSi3O10(OH)2 + 0.5 SO2 + 0.25 O2 → 0.5 K2SO4 + 3 MgO + 0.5 Al2O3 + 3 SiO2 + H2O
(vapor)
Low Temperature Calcite Decomposition:
2 CaCO3 + SiO2 → Ca2SiO4 + 2 CO2
2 MgO + SiO2 → Mg2SiO4
Ca5(PO4)3OH + 0.25 SiO2 → 1.5 Ca3(PO4)2 + 0.25 Ca2SiO4 + 0.5 H2O (vapour)
Alumina and Oxide Reaction:
12 CaCO3 + 7 Al2O3 → Ca12Al14O33 + 12 CO2
4 CaCO3 + Al2O3 + Fe2O3 → Ca4Al2Fe2O10 + 4 CO2
4 CaCO3 + Al2O3 + Mn2O3 → Ca4Al2Mn2O10 + 4 CO2
Reaction of Remaining Calcite:
CaCO3 → CaO + CO2
Sintering:
Ca2SiO4 + CaO → Ca3SiO5
Properties of Good Cement
It is always desirable to use the best cement in constructions. Therefore, the properties of a
cement must be investigated. Although desirable cement properties may vary depending on
the type of construction, generally a good cement possesses following properties (which
depend upon its composition, thoroughness of burning and fineness of grinding).
Provides strength to masonry.
Stiffens or hardens early.
Possesses good plasticity.
An excellent building material.
Easily workable.
Good moisture-resistant.
Proper field tests and laboratory tests should be done to ensure the qualities of the cement.
Uses of Cement
Cement is a very useful binding material in construction. The applications of cement over
various fields of construction have made it a very important civil engineering material.

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Some of the numerous functions of cement are given below.
 It is used in mortar for plastering, masonry work, pointing, etc.
 It is used for making joints for drains and pipes.
 It is used for water tightness of structure.
 It is used in concrete for laying floors, roofs and constructing lintels, beams, stairs, pillars
etc.
 It is used where a hard surface is required for the protection of exposed surfaces of
structures against the destructive agents of the weather and certain organic or inorganic
chemicals.
 It is used for precast pipes manufacturing, piles, fencing posts etc.
 It is used in the construction of important engineering structures such as bridges,
culverts, dams, tunnels, lighthouses etc.
 It is used in the preparation of foundations, watertight floors, footpaths etc.
 It is employed for the construction of wells, water tanks, tennis courts, lamp posts,
telephone cabins, roads etc.
How to check quality of cement on site?
Quality of cement on site: -
Cement is the most used material in any construction. It acts as a binder which binds aggregate
and sand together in concrete. Well, there are so many theories explained how to check the
quality of cement in the lab but most of them require huge apparatus to check the quality of
cement. t is not easy to check all properties of cement on the site but there exist some
preliminary field tests which can give us a rough idea about the quality of cement.
Below mentioned tests are the simple tests which you can perform easily on site to find out the
quality of cement with no apparatus. These preliminary tests include checking the properties of
cement which affect the Cement strength and quality.
1. Date of Packing (MFG Date):
Several studies stated that as the Strength of cement reduces as time goes on. As per IS
Specifications cement should be re tested if it is stored more than three months in the mill.
The below table gives details about the percentage of strength loss for different time
intervals.

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Age of cement Percentage of Cement Strength reduction
3 months 20%-30%
6 months 30%-40%
12 months 40%-50%
From the above table, it is clear that strength of cement loses its strength over a period of time.
2. Colour of Cement: –
The colour of cement should be uniform. An ideal colour of cement is grey with a light greenish
shade. Cement colour gives an indication of excess clay or lime.
3. Check for lumps: -
Lumps are formed due to the presence of moisture in cement. Cement undergoes a chemical
reaction when it is reacted with the atmospheric moisture this process is termed as hydration.
Moisture is a big enemy for cement. Cement becomes useless once it is hydrated with water
(liquid form or vapour form)

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4. Rubbing Test:
Take a pinch of cement rub within your fingers, it should feel smooth while rubbing. If it is
rough, it indicates that cement is mixed with sand.
5. Float test of cement: -
Take a handful of cement and throw it in water, a good quality of Cement should sink and
should not float on water.
6. Hand insertion: -
Insert your hand into the cement bag. It must give you a cool feeling. It implies that the no
hydration reaction taken place in cement bag,
7. Shape test of cement: -
Cement is also named as Hydraulic Cement as it also sets under water.
Take a 100g of cement and make a stiff paste by adding some water. Then prepare a cement
cake with sharp edges and place it on a glass plate. Immerse this plate in the water bucket.
Observe that the shape shouldn’t get disturbed while settling. A good cement should be able to
set and attain strength in water.
8. Strength test: –
Make A block of cement 25 mm x 25 mm and 200 mm long. Immerse the block in water for 7
days. Place the immersed block on supports 15000 mm apart and then load with a weight of
340 N. the block which is made of good cement should not show any sign of failure.
9. Specific Gravity of cement: -
Finding specific gravity of cement is utmost important if cement is stored for more than three
months. A good cement should have Specific gravity (Sg) in between 3.1-3.6g/cc.

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Chapter No 5
Types of Metals used in Civil Engineering
All metals used for engineering works are classified into:
A. Ferrous metals
B. Non-Ferrous metals: Wherein iron is not the main constituent (Copper, Aluminum, Zinc
and lead etc)
A) Ferrous metals:
Where in iron is the main constituent (Cast iron, wrought iron and different forms of steels)
Ferrous metals ► not directly obtained from iron ores
A-1) PIG IRON:
From iron ore ► impure form of metal ► Pig iron
It is the pig iron which further yields “Ferrous metals”
Pig iron is not suitable for any mechanical use unless it is converted into cast iron, wrought iron
or steel

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A-2) CAST IRON:
Pig iron ► re melted with limestone and coke and poured into moulds of desired shapes and
sizes to get purer product known as cast iron
Carbon content in cast iron varies from 2 to 5%
During re melting of pig iron ► scrap iron may also be added for economy
Properties of Cast Iron
1. It is brittle, non ductile, non malleable and cracks when subjected to shocks
2. It cannot be magnetized
3. It does not rust
4. It is strong in compression but weak in tension and shear
5. Its melting point is 12000C
6. Its specific gravity is 7.5
USES
Weak in tension therefore cannot be used in construction
Can be used for parts of pumps, motors, engines etc
Because of corrosion resistance ►can be used for pipes to some extent
A-3) WROUGHT IRON
When pig iron is melted in such a way as to remove all of the carbon and other impurities, the
result is wrought iron
Good quality wrought iron contains 99.5 % iron, less than 0.1 % of Silicon, 0.01 % of Sulfur,
0.07 % of phosphorus and 0.03 % of manganese.
Properties of Wrought Iron
1. Wrought iron is very malleable and ductile
2. Its tensile strength is 20-26 tons /in2
3. It is strong in compression but not so strong as steel
4. It can be easily worked, welded and is tough
5. Its melting point is 28000F
6. Wrought iron became pasty and very plastic at red heat and could be easily forged at
about 16500F
USES:

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Since mild steel has replaced the wrought iron, therefore it is no longer produced in large extent.
Still in use for roof sheets, wires and metal ornaments etc
A-4) STEEL
Steel is an alloy of iron and carbon. Pure iron’s strength remarkably increases when alloyed with
carbon. The tensile strength increases with increasing carbon content but the ductility reduces.
Steel having its properties because of the presence of carbon alone is called “Plain carbon steel”
PLAIN CARBON STEEL can further be classified as
1. Low carbon steel or mild steel:
The carbon content does not increase 0.25%
Soft and ductile ► mostly used for construction purpose
Uses ► Sheets, rods, wires, pipes, hammers, chains, shafts etc
2. Medium-carbon steel:
The carbon content is 0.25 to 0.5 %
Stronger than the mild steel slightly less ductile
Uses ► Shafts, connecting rods and rails etc
3. High- carbon steel:
Carbon content is above 0.5%
Harder and stronger than mild steel and medium carbon steel
Uses ► Keys, knifes, drills etc
Properties of Mild Steel
1. Ductile and malleable
2. It corrodes quickly
3. It can be permanently magnetized
4. It is tough and more elastic than cast iron and wrought iron and withstands shocks and
impacts well
5. It is equally strong in tension, compression and shear
6. Its specific gravity is 7.8
7. It is not much affected by Saline water

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Properties of High-carbon Steel
1. Its structure is granular
2. It is more tough and elastic than mild steel
3. It is easier to harden and then to weld
4. It is more difficult to forge and then to weld
5. It can be permanently magnetized
6. Comparatively it is stronger in compression than in tension or in shear
7. It withstands vibration and shocks better
Ferrous and Non-Ferrous Metals – Its Definition, List, Properties.
Ferrous Metals:
The ferrous group of metals includes all the types of iron, steel, and their alloys.
Actually Iron (Fe) is the principal element of Ferrous Materials.
In the present, their role in the engineering industries can be easily described as “most
dominating.”
In all the jobs ranging from the manufacture of a primitive type of agricultural implements to
advanced types of Air Crafts, ferrous metal and their alloys occupy a prominent position.
In the automotive, building and bridge construction, railways, light and heavy machinery,
shipping and transportation.
And in any other field of engineering activity, it may not be possible to move ahead without
metals. This is explained by a number of reasons:
1. The wide abundance of iron ore in almost all parts of the world.
2. The economical extraction of iron from its ore.
3. The flexibility that can be induced in the mechanical properties of iron by combining it
with other metals and/or by heat treatment and such other methods.
These facts explain the reason that for the considerable time, the annual global production
of Ferrous Metals has been far in excess than the combined production of all Non-Ferrous
Metals produced in all the countries of the world.
Ferrous Metals List | Their Types and Properties:
(1). Pig Iron:
Pig Iron is the first or basic form in which iron is prepared as a metal from its ores.
It is, therefore, impure and crude and requires subsequent processing to develop Cast, wrought
iron, and Steel, which are the common Ferrous Metal used in construction and industries.
Following are a few types of pig iron distinguished on the basis of their properties.

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Grey Pig Iron:>
It is also called foundry pig. It is soft in character and rich in carbon. It is produced when the raw
material is burnt at a very high temperature.
White Pig Iron:>
It is also called forge pig iron, as it is hard and brittle and can be converted only by using
pressure. This type contains sulfur as the main impurity and hence is considered inferior in
grade.
Bessemer Pig Iron:>
It is specially used in the manufacture of steel in the Bessemer process, because of its freedom
from sulfur and phosphorous.
(2). Cast Iron:
It consists of remelted pig iron -containing carbon 2-4 percent- and a small proportion of
manganese, silicon, and sulfur.
The remelting process is done in a special furnace called Cupola.
A Cupola is in essence to a small sized blast furnace. It is 5 meter in height, about 1 meter in
diameter and cylindrical in shape.
The cylinder has an inner lining of Refractory Bricks which is provided with Tuyers near the
bottom for injecting the supply of air blast.
Following are the common types of cast iron used in engineering materials.

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Grey Cast Iron:>
In this type, carbon is present in the flaky, graphite form. It has a typically grayish color -which is
due to graphite-. The usual composition of Grey cast iron is:
 Iron – 92 percent.
 Carbon – 3.5-4 percent (as graphite).
 Carbon – 0.5 percent (combined).
 Silicon – 2-3 percent.
It is soft and ductile. It is commonly used in castings, dies, molds, machine frames, and pipes,
etc.
White Cast Iron:>
It is that type in which carbon is present in the combined form as iron carbide (FeC), not
as graphite. It has a shining white color and a bright metallic white luster. It is very strong, hard
and resistant to Wear and Tear. And quite Brittle as well. Its usual composition is as follows:
 Iron – 94 percent.
 Carbon – 2.5-3.0 percent (as iron carbide -FeC-).
 Silicon -0.5-1.0 percent.
Malleable Cast Iron:>
It is actually “white cast iron” in which property of malleability has been developed by the
process of heat treatment.
The white cast iron is subjected to a process of annealing, i.e., heating in an annealing oven at a
temperature of 875 Centigrades for 24-72 hours.
After that, it is cooled gradually to room temperature. It is tough, ductile and strong. It
possesses useful properties of both cast iron and mild steels.

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Its common application is as follows:
 It is used in Automobile industries for making rear-axle housing, steering-gear housing,
hubs, and pedals, etc.
 It is used in Railway equipment of a great variety.
 It is used in Agricultural machinery making and carpentry tools.
Alloy Cast Iron:>
This group includes those types of cast iron in which one or more alloying elements have been
incorporated with a view of increasing the utility of the metal.
The usual alloying elements are Nickel and Chromium. Nickel is added to effect an increase in
the hardness and resistance to wear. Chromium makes the cast iron extremely tough, strong
and ductile.
Ductile, Inoculated, Controlled and Chilled cast irons are some other varieties of cast iron,
which is specially prepared for some specific applications.

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Properties of Cast Iron:
No generalization of cast iron is possible. This is because the ultimate properties of cast iron
depend on:
 It’s composition.
 The rate of cooling.
 The nature of heat treatment.
Following is a general account of the properties that depend on composition.
Carbon:
The amount and nature of carbon present in the cast iron greatly affect its properties. Thus,
When most of the carbon is present as graphite (free carbon) – Then it will be soft and weak,
e.g., Grey cast iron. But when the carbon is present as Cementite (fixed as Fe carbide), then the
metal will be hard and strong. Thus, Cast Iron can be both hard, strong, soft and weak.
The tensile strength decreases with an increase in the graphite content.
Alloying Elements:
The most important elements often added to cast iron, and their effects are the following:
Nickel: It may be added in amounts varying between 0.5-3 percent. The most common types of
alloyed nickel-iron are: Nickel, Chilled and High Nickel Cast Iron.
Chromium: It is also added in small proportion. The Addition of chromium increases hardness
and tensile strength. Generally, chromium and nickel are added together.
Molybdenum: It is specially added to increase hardness.
Heat Treatment:

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This type of treatment changes the properties of cast iron to a great extent. This type of
treatment effects the nature of carbon present in the metal. The combined carbon of cast iron
gets converted to free particles of carbon.
Impurities:
The influence of certain common impurities like phosphorous, sulfur, silicon, and manganese
also affect the quality of iron.
(3). Wrought Iron:
It is the purest form of Iron, containing all impurities below a limit of 0.5 percent. And carbon is
included in these impurities, its proportion being generally less than 0.12 percent.
Besides, wrought iron always contains a small proportion of slag in the silicate component.
The source material for the manufacture of wrought iron is PIG IRON. There are two processes
for the manufacture of wrought iron:
Puddling Process.
Aston Process.
Properties and Uses of Wrought Iron:
Its most important properties are mentioned below.
Strength: It has a tensile strength varying between 2500 to 4000 kg/cm2. The strength will be
greater in the longitudinal direction. The ultimate compressive strength ranges between 1500-
2000 kg/cm2.
Physical: Wrought Iron is bluish in color, has a silky lustre and fibrous structure. It is malleable,
ductile, tough and resistant to corrosion.
Density: The metal has a density of 7.8 gm/cm3, and a melting point of 1500 centigrade.
Wrought iron shows good resistance to fatigue and sudden shock. More ever it can be welded
with ease. Because of the above set of properties, wrought iron is extensively used as a

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material for making plates, sheets, pipes, tubes, etc. It is also used in buildings, railways, and
marine industries.
(4). Steel:
Steel is essentially a variety of iron-containing 0.1 to 1.5 percent carbon in the form
of cementite iron carbide – Fe3C –). Besides carbon, many other metals may also be present in
addition to iron, giving rise to great varieties of steel.
If the percentage of carbon exceeds 1.5 percent, the material will become more like cast iron
because the carbon will then tend to occur as graphite (free carbon).
On the other hand, with the decrease in the carbon content (lower than 0.1%), the material
would resemble more to wrought iron or pure iron.
The best thing about steel is that it has both properties of Cast and Wrought Iron – Compressive
Strength of cast iron and Tensile Strength of wrought iron.
Due to these properties, Steel is used as a structural material in all types of situations.
Steel is a versatile material of modern age. Its properties can be varied over a wide range by
varying its composition and by subjecting it to various mechanical and heat treatment
processes.
Classification of Steels:
Steels can be classified in many ways such as on the basis of the methods used in their
manufacture, on the carbon content, or according to their use. It can also be classified on the
basis of steel casting. It is, however, the classification on the basis of their chemical composition
is commonly adopted. Following are the major groups of steels.
Plain Carbon Steels:
This is the first major group of steels. Carbon is the only controlling component in them besides
iron. They are further subdivided into 3 subcategories.

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 Low Carbon Steels (C=0.05-0.25%)
 Medium Carbon Steels (C=0.25-0.50%)
 High Carbon Steels (C=0.50-1.50%)
Alloy Steels:
These are steels made with the addition of a definite proportion of a selected element or
elements in addition to carbon at the manufacturing stage. Benefits of alloying are as follow:
 The tensile strength of the steel may be increased without affecting its workability.
 The resistance against very high temperature, abrasion and corrosion may be improved
considerably.
 The electrical, magnetic and thermal properties may be modified in the desired
direction.
They can be sub-divided into 2 types on the basis of the proportion of alloying elements, which
are the following:
 Low Alloy Steels.
 High Alloy Steels.
So, finally, Ferrous Metals List comes to an end. So, now let’s move on to the Non Ferrous
Metals.
Non Ferrous Metals:
As we know that many Ferrous Metals like steel and iron is used commonly in buildings and
engineering industries.
But many non ferrous metals and alloys have also been used to great advantage in both
buildings and industries.
In fact, in some cases, they form far better materials than iron and steel and have replaced
them to a great extent.
However, the non-ferrous metals are comparatively costlier and are selected for use only when
they satisfy certain specific requirements and possess some definite properties.
Following are the special advantages of non-ferrous metals over ferrous metals in some
selected areas.
In Civil Engineering Construction, Aluminum and some of its alloys offer a very suitable
alternative material to steel in some special engineering construction. Thus, wrought aluminum
alloys are:
 Economical;
 Resistant to Corrosion;
 Light in Weight;
Compared to steels, they have been used in i.e., construction of bridges and roofs in situations
where not much strength is required.
In these situations, they have been found to save 50% of extra weight.

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In Engineering Industries, Copper, zinc, nickel, and chromium in their pure and alloyed forms
have been used as materials in situations where:
 High tensile strength is required at elevated temperatures.
 High ductility and malleability are required.
 High resistance to heat is required.
 High electrical conductivity is required.
In the above fields and situations, mostly non ferrous metals are used.
Non Ferrous Metals List:
(1). Aluminum:
Aluminum is a very common component (about 8 percent) of the earth crust, the most
common ore of aluminum is Bauxite (Al2O3. n H2O). As a metal, aluminum was first discovered
in 1825.
Aluminum Properties:
Following are some important properties of this metal.
 It is a white metal and shows brilliant lustre when fresh.
 It is very ductile and can be transformed into any shape by rolling, stamping, extruding,
forging, drawing, and spinning.
 It can also be cast into any shape by any method of casting, i.e., die casting, chill casting,
and sand casting.
 It has a tensile strength of about 900kg/cm2 in the annealed condition. It can be
improved to 1600kg/cm2 by the hard-rolling method.

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 Aluminum is highly resistant to corrosion. When exposed to moist air, aluminum forms a
thin film of oxide at the top, which is impervious to air/moisture, and thus saves the
metal from further corrosion.
Following are the alloys of aluminum.
Aluminum Alloys:
Following are alloys of aluminum.
 Wrought aluminum alloys.
 Casting aluminium alloys.
(2). Copper:
Metallic copper and its various alloys have been used in engineering industries and for many
other activities from 100 of years.
This is due to some of the useful properties of copper. Some of the most important properties
of copper are as under:
 It is very malleable and ductile so that it can be converted into any desired shape.
 It has excellent joining properties, i.e., it can be joined by almost all the common
methods: welding, soldering, brazing and riveting.
 It has a very high electrical conductivity.
 It forms excellent alloys.
 It has good resistance to corrosion.
Copper Properties:
Following are some important properties of copper metal:
 It has a reddish color and a bright lustre.
 It is highly malleable and ductile.
 It has a melting point of 1083 centigrade and boiling point of 2595 centigrade.

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 The metal is quite resistant to corrosion.
 Its specific gravity is 8.93.
Copper Alloys:
Following are alloys of copper:
 Brasses.
 Bronzes.
(3). Lead:
Lead has been used for centuries in buildings and other engineering industries. Lead is
extracted from three chief ore minerals.
 Galena
 Cerrusite
 Anglesite
Lead Properties:
The metallic lead has following properties.
 It has bluish Grey color.
 It has typically brilliant lustre.
 It has a high density – 11.35 g/cm3.
 It has a low melting point of 327 centigrade.
 It has a high boiling point of 1744 centigrade.
 It is very good to resistance to corrosion.

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Lead Alloys:
In general, lead doesn’t form many alloys. Its alloying capacity is limited because of its low
melting point. Following are more important alloys of lead.
 Solder
 Terne plate
 Type metal
 Bearing metal
(4). Zinc:
Zinc is another non ferrous metal. The chief ore mineral of zinc is sulfide called sphalerite.
Smithsonite, Zincite (ZnO) and Calamine (ZnCO3) are other common zinc minerals.
Zinc Properties:
Following are some important properties of Zinc.
 It is whitish and has bright lustre.
 It has a density of 7.14 g/ml.
 Its melting point is 419 centigrade and boiling point is 907 centigrade.
 It has a tensile strength of 700-1400 kg/cm2.
 Commercial zinc (spelter) is easily attacked by acids.
 Zinc surface is covered by a dull basic zinc carbonate in moist air.
(5). Nickel:
Nickel was first discovered in 1750. It is manufactured from its sulfide ore
named pentlandite [NiFe(S)].
The ore is first concentrated by froth flotation process and then roasted and smelted like
other non ferrous metals.

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Nickel Properties:
Following are some important properties of nickel.
 It is the strongest metal in all the non ferrous metals, having tensile strength ranges
from 4200-8400 kg/cm2.
 It is highly resistant to many types of corrosion. Thus it can withstand in water, moisture
atmospheric gases, etc.
 Its modulus of elasticity, thermal and electrical conductivity is the same as steel.
 It is highly malleable and ductile.
 Its density is 8.9 g/cm3.
 Its melting point is 1455 centigrade.
(6). Magnesium:
Magnesium forms the lightest materials used in structural engineering. It has a set of properties
that make it suitable as an engineering material.

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Magnesium Properties and uses:
Magnesium is a very useful metal both as a pure metal and in alloys its main properties are as
follows:
 It is very light with a specific gravity of 1.74.
 Its melting point is 650 centigrade, which is similar to that of aluminum.
 It has a poor corrosion resistant.
 It has quite high thermal conductivity and a high coefficient of thermal expansion.
 It forms very useful alloys with some metals like aluminum, thorium, zinc, zirconium,
and tin, etc.
Chapter No 06
Glass:
Silica is the main constituent of glass. But it is to be added with sodium potassium carbonate to
bring down melting point. To make it durable lime or lead oxide is also added. Manganese oxide
is added to nullify the adverse effects of unwanted iron present in the impure silica. The raw
materials are ground and sieved. They are mixed in specific proportion and melted in furnace.
Then glass items are manufactured by blowing, flat drawing, rolling and pressing.
Important Properties of Glass
1. It absorbs, refracts or transmits light. It can be made transparent or translucent.
2. It can take excellent polish.
3. It is an excellent electrical insulator.
4. It is strong and brittle.
5. It can be blown, drawn or pressed.
6. It is not affected by atmosphere.
7. It has excellent resistance to chemicals.

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8. It is available in various beautiful colours.
9. With the advancement in technology, it is possible to make glass lighter than cork or stronger
than steel.
10. Glass panes can be cleaned easily.
Types of Glass
The glass may be broadly classified as:
1. Soda-lime glass, 2. Potash lime glass, 3. Potash lead glass 4. Common glass and
5. Special glasses.
1. Soda Lime Glass: It is mainly a mixture of sodium silicate and calcium silicate. It is fusible
at low temperature. In the fusion condition it can be blown or welded easily. It is colourless.
It is used as window panes and for the laboratory tubes and apparatus.
2. Potash Lime Glass: It is mainly a mixture of potassium silicate and calcium silicate. It is also
known as hard glass. It fuses at high temperature. It is used in the manufacture of glass
articles which have to with stand high temperatures.
3. Potash Lead Glass: It is mainly a mixture of potassium silicate and lead silicate. It possesses
bright lustre and great refractive power. It is used in the manufacture of artificial gems,
electric bulbs, lenses, prisms etc.
4. Common Glass: It is mainly a mixture of sodium silicate, calcium silicate and iron silicate. It
is brown, green or yellow in colour. It is mainly used in the manufacture of medicine bottles.
5. Special Glasses: Properties of glasses can be suitably altered by changing basic ingradients
and adding few more ingradients. It has now emerged as versatile material to meet many
special requirement in engineering. The following is the list of some of the special glasses:
(a) Fibre glass (b) Foam glass
(c) Bullet proof glass (d) Structural glass
(e) Glass black (f) Wired glass
(g) Ultraviolet ray glass (h) Perforated glass.
Principal constituents and their functions
Constituents of Glass and their main functions
The various constituents and their functions are explained below:
1. SILICA:
 It is the main constituent of all kinds of glass.
 If silica only used in the manufacture of glass, it could be fused at a very high
temperature but it will give a good glass on cooling. Since it fuses at very high
temperatures some alkaline admixture like sodium carbonate or potassium carbonate is
added to make it fuse at lower temperature.

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 The admixture also makes the liquid silica more viscous and better workable.
2. POTASSIUM CARBONATE
 It is an essential component of glass; it is an alkaline.
 This renders glass in-fusible and give fire resisting properties to it.
3. SODIUM CARBONATE:
 It is an alkaline.
 It is added in suitable proportion to reduce the melting point of silica and to impart
viscosity to the molten metal.
 It quickens the fusion of glass and as such excess of it is harmful.
4. LIME:
 It is added in the form of chalk.
 It imparts durability and toughness to the glass.
5. LEAD OXIDE:
 It makes glass bright and shining.
 It gives color to the glass and therefore its presence in glass is not much desirable.
6. MANGANESE DIOXIDE:
 It is also called as "glass makers soap", because it is used either remove color from glass
or add color to it.
 It is added in suitable proportions to correct the color of glass due to the presence of
iron in raw materials of glass.
7. CULLET:
 It is broken glass of the type desired to be manufacture that is added as a raw material
to bring down the cost of production.
 It is added in small quantity to provide body to the glass.
8. COLOURING SUBSTANCES:
From many years ago glassmaker was adding substances to glass's raw material or batch to
produce coloured glass. Many of the substances used in the making of coloured glass by our
forefathers can no longer be used due to their properties, which contravene all aspects of
health and safety in the work place.
Metals Used to Impart Color to Glass

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Cadmium Sulfide Yellow
Gold Chloride Red
Cobalt Oxide Blue-Violet
Manganese Dioxide Purple
Nickel Oxide Violet
Sulfur Yellow-Amber
Chromic Oxide Emerald Green
Uranium Oxide Fluorescent Yellow, Green
Iron Oxide Greens and Browns
Selenium Oxide Reds
Carbon Oxides Amber Brown
Antimony Oxides White
Copper Compounds Blue, Green, Red
Tin Compounds White
Lead Compounds Yellow
Manganese Dioxide A "decoloring" agent
Sodium Nitrate A "decoloring" agent
There are also other factors, which have to be taken into consideration when producing
coloured glass: -
1. The temperature of the melt/bath.

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2. Temperature of reheat during the working of glass.
3. The temperature of the 'Lehr' (Annealing oven)
4. Duration of the melt/batch.
5. Time and temperature relationship at different stages in production.
6. The type of colorant being used.
7. Concentration of the colorant.
8. Atmosphere of the furnace.
9. The composition of the colorant within the glass composition as is the case when iron is
added to the glass. The type of iron oxide formed decides if the glass will be blue or
yellow.
10. The number of times the same glass is melted. (Repeated melting of the cullet will
usually give a darker tone to the finished piece.).
Types of Glass and its Engineering Properties for Use in Construction
There are various types of glass used in construction for different purposes. Engineering
properties and uses of these glass is discussed in this article.
Glass is a hard substance which may be transparent or translucent and brittle in nature. It is
manufactured by fusion process. In this process sand is fused with lime, soda and some other
admixtures and then cooled rapidly. Glass is used in construction purpose and architectural
purpose in engineering.
Engineering Properties of Glass
 Transparency

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 Strength
 Workability
 Transmittance
 U value
 Recycle property
Transparency of Glass
Transparency is the main property of glass which allows the vision of outside world through it.
The transparency of glass can be from both sides or from one side only. In one side
transparency, glass behaves like mirror from the other side.
Strength of Glass
Strength of glass depends on modulus of rupture value of glass. In general glass is a brittle
material but by adding admixtures and laminates we can make it as more strong.
Workability of Glass
A glass can be molded into any shape or it can be blown during melting. So, workability of glass
is superior property of glass.
Transmittance
The visible fraction of light that passing through glass is the property of visible transmittance.
U value of Glass
U value represents the amount of heat transferred through glass. If a glass is said to be
insulated unit then it should have lower u value.
Recycle Property of Glass
Any glass can be 100% recyclable. It can also be used as raw material in construction industry.
Types of Glass and their Uses in Construction Works
The types of glass used in construction are:
 Float glass
 Shatterproof glass
 Laminated glass
 Extra clean glass
 Chromatic glass
 Tinted glass
 Toughened glass
 Glass blocks
 Glass wool
 Insulated glazed units
Float Glass

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Float glass is made of sodium silicate and calcium silicate so; it is also called as soda lime glass.
It is clear and flat so, it causes glare. These glasses are available from 2mm to 20mm thickness
ranges. They have a weight range of 6 to 36 kg/m2. These are used as shop fronts, public places
etc.
Shatterproof Glass
Shatterproof glass is used for windows, skylights, floors etc. Some type of plastic polyvinyl
butyral is added in its making process. So, it cannot form sharp edged pieces when it breaks.
Laminated Glass
Laminated glass is the combination of layers of normal glass. So, it has more weight than
normal glass. It has more thickness and is UV proof and soundproof. These are used for
aquariums, bridges etc.

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Extra Clean Glass
Extra clean glass has two special properties, photocatalytic and hydrophilic. Because of these
properties, it acts as stain proof and gives beautiful appearance. Maintenance is also easy.
Chromatic Glass
Chromatic glass is used in ICU’s, meeting rooms etc. it can control the transparent efficiency of
glass and protects the interior from daylight. The chromatic glass may be photochromic which
has light sensitive lamination, thermos-chromatic which has heat sensitive lamination and
electrochromic which has electric lamination over it.

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Tinted Glass
Tinted glass is nothing but colored glass. A color producing ingredients is mixed to the normal
glass mix to produce colored glass which does not affect other properties of glass. Different
color producing ingredients are tabulated below
Coloring ion Color
Iron oxide Green
Sulphur Blue
Manganese dioxide Black
Cobalt Blue
Chromium Dark green
Titanium Yellowish brown
Uranium yellow

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Toughened Glass
Toughened glass is strong glass which has low visibility. It is available in all thicknesses and
when it is broken it forms small granular chunks which are dangerous. This is also called as
tempered glass. This type of glass is used for fire resistant doors, mobile screen protectors etc.
Glass Blocks
Glass block or glass bricks are manufactured from two different halves and they are pressed
and annealed together while melting process of glass. These are used as architectural purpose

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in the construction of walls, skylights etc. They provide aesthetic appearance when light is
passed through it.
Glass Wool
Glass wool is made of fibers of glass and acts as good insulating filler. It is fire resistant glass.
Insulated Glazed Units
Insulated glazed glass units contains a glass is separated into two or three layers by air or
vacuum. They cannot allow heat through it because of air between the layers and acts as good
insulators. These are also called as double glazed units.

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Plastics
Plastic is an organic material prepared out of resin. It may or may not contain fillers, plasticisers
and solvents. Plastic may be defined as a natural or synthetic organic material which are having
the property of being plastic at some stage of their manufacture when they can be moulded to
required size and shape.
Shellac and bitumen are the natural resins used as plastic for a long time. In 1907, Blackland
produced synthetic resin from the reaction of phenol and formaldehyde. The resin was
hardened under pressure and heat to produce useful plastic articles.
Types of Plastics
Primarily there are two types of plastics:
1. Thermosetting and
2. Thermoplastic.
1. Thermosetting Plastics: It needs momentary heated condition and great pressure during
shaping. When heated cross linkage is established between the molecules and chemical
reaction takes place. During this stage shape can be changed with pressure. This change is not
reversible. The scrap of such plastic is not reusable. Bakelite is an example of such plastic.
2. Thermoplastic: In this variety, the linkage between the molecules is very loose. They can be
softened by heating repeatedly. This property helps for reuse of waste plastic. These plastic
need time to cool down and harden. These plastics are to be kept in moulds till cooling takes
place completely. Bitumen, cellulose and shellac are the examples of this variety of plastics.
Properties of Plastics
1. Colour: Some plastics are completely transparent. Using pigments plastics of any attractive
colour can be produced.
2. Dimensional Stability: It is dimensionally stable to a great extent.
3. Durability: Plastic offers great resistance to moisture and chemicals and hence more durable.
4. Electrical Insulation: The plastics possess excellent electrical insulating property.
5. Fire Resistance: The phenol-formaldehyde and urea-formaldehyde plastics resist fire to a
great extent and hence they are used as fire proofing materials.

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6. Strength: The plastics are reasonably strong. Their strength may be increased by reinforcing
with various fibrous materials. Attempts are being made to produce structurally sound plastics.
7. Specific Gravity: The specific gravity of plastics is very low and hence convenient to handle.
8. Ductility: The plastics are not ductile and hence they fail without giving warning.
9. Fixing: Plastics can be bolted, drilled, glued, clamped or simply push fitted in position.
10. Maintenance: There is no maintenance cost for plastic articles i.e., they do not need
painting and polishing.
Uses of Plastics
There are variety of plastics made to suit different uses. The typical uses of plastics in buildings
is listed below:
1. Corrugated and plain sheets for roofing.
2. For making jointless flooring.
3. Flooring tiles.
4. Overhead water tanks.
5. Bath and sink units.
6. Cistern hall floats.
7. Decorative laminates and mouldings.
8. Window and door frames and shutters for bathroom doors.
9. Lighting fixtures.
10. Electrical conduits.
11. Electrical insulators.
12. Pipes to carry cold waters.
Properties and Uses of Plastics as a Construction Material
Properties of Plastics as a Construction Material
Each plastic material has its own peculiar properties to suit its particular uses. The success of
plastic as an engineering material will depends up on the selection of variety of plastic.
Following are the general properties of plastic.
1. Appearance
2. Chemical resistance
3. Dimensional stability
4. Ductility
5. Durability
6. Electric insulation
7. Finishing
8. Fire resistance
9. Fixing
10. Humidity

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11. Maintenance
12. Melting point
13. Optical property
14. Recycling
15. Sound absorption
16. Strength
17. Thermal property
18. Weather resistance
19. Weight
1. Appearance of Plastics
In the market there are so many types of models of plastics are available such as transparent,
colored etc. suitable pigments are added in the process of manufacturing of plastic material to
get these different properties. So, these will give good appearance to the structure and makes
it attractive.
2. Chemical Resistance of Plastics
Plastics offer great resistance against chemicals and solvents. Chemical composition of plastics
during manufacturing will decide the degree of chemical resistance. Most of the plastics
available in the market offer great corrosion resistance. So, corrosive metals are replaced by
plastic in the case of water carrying pipes, etc.
3. Dimensional Stability

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Thermo-plastic types of plastics can be easily reshaped and reused. But in the case of thermo-
setting type plastics, it is not possible to reshape or remold the material.
4. Ductility of Plastics
Ductile nature of plastic is very low. When tensile stress is acting on plastic member they may
fail without any prior indication.
5. Durability of Plastics
Plastics with sufficient surface hardness are having good durability. Sometimes, plastics may
have affected by termites and rodents especially in the case of thermo-plastic types, however it
is not a serious problem because of no nutrition values in plastic.
6. Electric Insulation
Plastics are good electric insulators. So they are used as linings for electric cables and for
electronics tools.
7. Finishing
Any type of finishing treatment van be given to the plastics. Mass production of plastic particles
with uniformity of surface finish is done by having technical control during manufacturing.
8. Fire Resistance
The resistance to temperature or fire for varieties of plastics considerably varies depending
upon the structure. Plastics made of cellulose acetate are burnt slowly. PVC made plastics do

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not catch fire easily. Plastics made of phenol formaldehyde and urea formaldehyde are fire
proof materials.
9. Fixing
Fixing of plastic materials is so easy. We can bolt, drill or glued to fix plastic material position.
10. Humidity
The plastics made up of cellulosic materials are affected by the presence of moisture. The
plastics made of poly vinyl chloride (PVC pipes) offers great resistance against moisture.
11. Maintenance
Maintaining of plastics are so simple. Because they do not need any surface finishing coats or
paints etc.
12. Melting Point
Generally, plastics have very low melting point. Some plastics may melt at just 50oC. So, they
cannot be used in the positions of high temperature. Thermo setting type of plastics are having
high melting point than thermo plastic type plastics. However, thermo setting types are cannot
used for recycling. To improve the heat resistance of the plastics, glass fiber reinforcement is
provided in its structure.
13. Optical Property

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There are so many types of plastics. Some plastics are transparent which allows light in its
original direction and some are translucent nothing but semi-transparent which allows light but
changes light rays direction.
14. Recycling of Plastics
Disposal of plastics in the environment causes severe pollution. But it is not a serious problem
because of its recycling property. We can use plastic waste disposal conveniently to produce
drainage pipes, fencing, hand rails, carpets, benches etc.
15. Sound Absorption

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By the saturation of phenolic resins, we can produce acoustic boards. These acoustic boards are
sound absorbents and provide sound insulation. Generally, for theatres, seminar halls this type
of acoustic ceilings are used.
16. Strength
Practically we can say that plastic is strong material but ideal section of plastic which is useful
for structural component is not designed yet. Generally, by reinforcing fibrous material into
plastic improves its strength. If the strength to weight ratio of plastic is same as metals, then
also we cannot give preference to plastics because of various reasons like, heavy cost, creep
failure may occur, poor stiffness and sensitive against temperature.
17. Thermal Property
The thermal conductivity of plastics is very low and is similar to wood. So, foamed and
expanded plastics are used as thermal insulators.

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18. Weather Resistance
Most of the plastics except some limited varieties are capable of resistance against weathering.
But, major problem is plastics when the plastics are exposed to sunlight, they are seriously
affected by ultra violet rays and gets brittle. To prevent this, plastics are incorporated by fillers
and pigments which helps to absorb or reflect the UV rays to surface.

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19. Weight of Plastics
The Plastics have low specific gravity generally ranges from 1.3 to 1.4. So they are light in
weight and easily transportable to any place in a large quantity.
Chapter No 7
Timber
Timber refers to wood used for construction works. In fact, the word timber is derived from an
old English word ‘Timbrian’ which means ‘to build’. A tree that yields good wood for
construction is called ‘Standing Timber.’ After felling a tree, its branches are cut and its stem is
roughly converted into pieces of suitable length, so that it can be transported to timber yard.
This form of timber is known as rough timber. By sawing, rough timber is converted into various
commercial sizes like planks, battens, posts, beams etc. Such form of timber is known as
converted timber.
Timber was used as building material even by primitive man. Many ancient temples, palaces
and bridges built with timber can be seen even today.
Classification of Timber
Various bases are considered for the classification of timbers. The following are the important
basis:
(i) Mode of growth
(ii) Modulus of elasticity
(iii) Durability
(iv) Grading
(v) Availability.
(i) Classification Based on Mode of Growth: On the basis of mode of growth trees are classified
as (a) Exogeneous and (b) Endogeneous
(a) Exogeneous Trees: These trees grow outward by adding distinct consecutive ring every
year. These rings are known as annual rings. Hence it is possible to find the age of timber by
counting these annual rings. These trees may be further divided into (1) coniferrous and (2)
deciduous. Coniferrous trees are having cone shaped leaves and fruits. The leaves do not fall till
new ones are grown. They yield soft wood.
Deciduous trees are having broad leaves. These leaves fall in autumn and new ones appear in
springs. They yield strong wood and hence they are commonly used in building construction.
The classification as soft wood and hard wood have commercial importance. The difference
between soft wood and hard wood is given below:
1. In soft wood annual rings are seen distinctly whereas in hard wood they are indistinct.
2. The colour of soft wood is light whereas the colour of hard wood is dark.
3. Soft woods have lesser strength in compression and shear compared to hard woods.
4. Soft woods are light and hard woods are heavy.
5. Fire resistance of soft wood is poor compared to that of hard wood.

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6. The structure of soft wood is resinous while structure of hard wood is close grained.
The cross-section of a exogeneous tree is as shown in the Fig. 1.7. The following components
are visible to the naked eye:
1. Pith: It is the inner most part of the tree and hence the oldest part of exogeneous tree when
the plant becomes old, the pith dies and becomes fibrous and dark. It varies in size and shape.
2. Heart Wood: This is the portion surrounding pith. It is dark in colour and strong. This portion
is useful for various engineering purpose. This is the dead part of wood. It consists of several
annular rings.
3. Sap Wood: It is the layer next to heart wood. It denotes recent growth and contains sap. It
takes active part in the growth of trees by allowing sap to move in upward direction. The annual
rings of sap wood are less sharply divided and are light in colour. The sap wood is also known as
alburnum.
4. Cambium Layer: It is a thin layer of fresh sap lying between sap wood and the inner bark. It
contains sap which is not yet converted into sap wood. If the bark is removed and cambium
layer is exposed to atmosphere, cells cease to be active and tree dies.
5. Inner Bark: It is an inner skin of tree protecting the cambium layer. It gives protection to
cambium layer.
6. Outer Bark: It is the outer skin of the tree and consists of wood fibres. Sometimes it contains
fissures and cracks.
7. Medullary Rags: These are thin radial fibres extending from pith to cambium layer. They
hold annular rings together. In some of trees they are broken and some other they may not be
prominent.
(b) Endogeneous Trees: These trees grow inwards. Fresh fibrous mass is in the inner most
portion. Examples of endogenous trees are bamboo and cane. They are not useful for structural
works.
(ii) Classification Based on Modulus of Elasticity: Young’s modulus is determined by
conducting bending test. On this basis timber is classified as:
Group A: E = 12.5 kN/mm2
Group B: E = 9.8 kN/mm2 to 12.5 kN/mm2

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Group C: E = 5.6 kN/mm2 to 9.8 kN/mm2.
(iii) Classification Based on Durability: Durability tests are conducted by the forest research
establishment. They bury test specimen of size 600 × 50 × 50 mm in the ground to half their
length and observe their conditions regularly over several years. Then timbers are classified as:
High durability: If average life is more than 10 years.
Moderate durability: Average life between 5 to 10 years.
Low durability: Average life less than 5 years.
(iv) Classification Based on Grading: IS 883-1970 classifies the structural timber into three
grades-select grade, grade I and grade II. The classification is based on permissible stresses,
defects etc.
(v) Classification Based on Availability: Forest departments classify timbers based on the
availability as
X—Most common. 1415 m3 or more per year
Y—Common. 355 m3 to 1415 m3 per year
Z—Less common. Less than 355 m3 per year.
Properties of Timber
Properties of good timbers are:
Colour: It should be uniform.
Odour: It should be pleasant when cut freshly.
Soundness: A clear ringing sound when struck indicates the timber is good.
Texture: Texture of good timber is fine and even.
Grains: In good timber grains are close.
Density: Higher the density stronger is the timber.
Hardness: Harder timbers are strong and durable.
Warping: Good timber do not warp under changing environmental conditions.
Toughness: Timber should be capable of resisting shock loads.
Abrasion: Good timber do not deteriorate due to wear. This property should be looked into, if
timber is to be used for flooring.
Strength: Timber should have high strength in bending, shear and direct compression.
Modulus of Elasticity: Timber with higher modulus of elasticity are preferred in construction.
Fire resistance: A good timber should have high resistance to fire.
Permeability: Good timber has low water permeability.
Workability: Timber should be easily workable. It should not clog the saw.
Durability: Good timber is one which is capable of resisting the action of fungi and insects
attack
Defects: Good timber is free from defects like dead knots, shakes and cracks.

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Seasoning of Timber
This is a process by which moisture content in a freshly cut tree is reduced to a suitable level. By
doing so the durability of timber is increased. The various methods of seasoning used may be
classified into:
(i) Natural seasoning
(ii) Artificial seasoning.
(i) Natural Seasoning: It may be air seasoning or water seasoning. Air seasoning is carried out
in a shed with a platform. On about 300 mm high platform timber balks are stacked as shown in
Fig. 1.8. Care is taken to see that there is proper air circulation around each timber balk. Over a
period, in a natural process moisture content reduces. A well seasoned timber contains only
15% moisture. This is a slow but a good process of seasoning.
Water seasoning is carried out on the banks of rivers. The thicker end of the timber is kept
pointing upstream side. After a period of 2 to 4 weeks the timber is taken out. During this
period sap contained in the timber is washed out to a great extent. Then timber is stalked in a
shed with free air circulation.
(ii) Artificial Seasoning: In this method timber is seasoned in a chamber with regulated heat,
controlled humidity and proper air circulation. Seasoning can be completed in 4 to 5 days only. The
different methods of seasoning are:
(a) Boiling
(b) Kiln seasoning
(c) Chemical seasoning
(d) Electrical seasoning.
(a) Boiling: In this method timber is immersed in water and then water is boiled for 3 to 4 hours. Then it
is dried slowly. Instead of boiling water hot steam may be circulated on timber. The process of seasoning
is fast, but costly.
(b) Kiln Seasoning: Kiln is an airtight chamber. Timber to be seasoned is placed inside it. Then
fully saturated air with a temperature 35°C to 38°C is forced in the kiln. The heat gradually reaches

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inside timber. Then relative humidity is gradually reduced and temperature is increased, and maintained
till desired degree of moisture content is achieved.
The kiln used may be stationary or progressive. In progressive kiln the carriages carrying timber
travel from one end of kiln to other end gradually. The hot air is supplied from the discharging end so
that temperature increase is gradual from charging end to discharging end. This method is used for
seasoning on a larger scale.
(c) Chemical Seasoning: In this method, the timber is immersed in a solution of suitable salt.
Then the timber is dried in a kiln. The preliminary treatment by chemical seasoning ensures uniform
seasoning of outer and inner parts of timber.
(d) Electrical Seasoning: In this method high frequency alternate electric current is passed through
timber. Resistance to electric current is low when moisture content in timber is high. As moisture
content reduces the resistance reduces. Measure of resistance can be used to stop seasoning at
appropriate level.
However, it is costly process. This technique has been tried in some plywood industries but not
in seasoning of timber on mass scale.
Defects in Timber
Various defects which are likely to occur in timber may be grouped into the following three:
(i) Due to natural forces
(ii) Due to defective seasoning and conversions.
(iii) Due to attack by fungi and insects.
(i) Defects due to Natural Forces: The following defects are caused by natural forces:
(a) Knots, (b) Shakes, (c) Wind cracks, (d) Upsets.
(a) Knots: When a tree grows, many of its branches fall and the stump of these branches in the
trunk is covered. In the sawn pieces of timber, the stump of fallen branches appear as knots.
Knots are dark and hard pieces. Grains are distorted in this portion. Figure 1.9 shows some
varieties of knots. If the knot is intact with surrounding wood, it is called live knot. If it is not
held firmly it is dead knot.

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(b) Shakes: The shakes are cracks in the timber which appear due to excessive heat, frost or
twisting due to wind during the growth of a tree. Depending upon the shape and the positions
shakes can be classified as star shake, cup shake, ring shakes and heart shakes [Ref. Fig. 1.10].
(c) Wind Cracks: These are the cracks on the outside of a log due to the shrinkage of the
exterior surface. They appear as shown in Fig. 1.11.
(d) Upsets: Figure 1.12 shows a typical upset in a timber. This type of defect is due to excessive
compression in the tree when it was young. Upset is an injury by crushing. This is also known as
rupture.
(ii) Defects due to Defective Seasoning and Conversion: If seasoning is not uniform, the
converted timber may warp and twist in various directions. Sometimes honey combining and
even cracks appear. This type of defects are more susceptible in case of kiln seasoning.
In the process of converting timber to commercial sizes and shapes the following types of
defects are likely to airse: chip marks, torn grain etc.
(iii) Defects due to Fungi and Insects Attack: Fungi are minute microscopic plant organism.

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They grow in wood if moisture content is more than 20°C and exposed to air. Due to fungi
attack rotting of wood, takes place. Wood becomes weak and stains appear on it.
Beetles, marine borers and termites (white ants) are the insects which eat wood and weaken
the timber. Some woods like teak have chemicals in their compositions and resist such attacks.
Other woods are to be protected by chemical treatment.
Preservation of Timber
Preservation of timber means protecting timber from fungi and insects attack so that its life is
increased. Timber is to be seasoned well before application of preservatives. The following are
the widely used preservatives:
1. Tar
2. Paints
3. Chemical salt
4. Creosote
5. ASCO
1. Tar: Hot coal tar is applied to timber with brush. The coating of tar protects the timber from
the attack of fungi and insects. It is a cheapest way of protecting timber. Main disadvantage of
this method of preservation is that appearance is not good after tar is applied it is not possible
to apply other attractive paints. Hence tarring is made only for the unimportant structures like
fence poles.
2. Paints: Two to three coats of oil paints are applied on clean surface of wood. The paint
protects the timber from moisture. The paint is to be applied from time to time. Paint improves
the appearance of the timber. Solignum paint is a special paint which protects the timber from
the attack of termites.
3. Chemical salt: These are the preservatives made by dissolving salts in water. The salts used
are copper sulphate, masonry chloride, zinc chloride and sodium fluoride. After treating the
timber with these chemical salt paints and varnishes can be applied to get good appearance.
4. Creosote: Creosote oil is obtained by distillation of coal tar. The seasoned timber is kept in
an air tight chamber and air is exhausted. Then creosote oil is pumped into the chamber at a
pressure of 0.8 to 1.0 N/mm2 at a temperature of 50°C. After 1 to 2 hours timber is taken out of
the chamber.
5. ASCO: This preservative is developed by the Forest Research Institute, Dehradun. It consists
of 1 part by weight of hydrated arsenic pentoxide (As2O5, 2 H2O), 3 parts by weight of copper
sulphate (CuSO4⋅5 H2O) and 4 parts by weight of potassium dichromate (K2Cr2O7) or sodium
dichromate (Na2Cr2O7⋅2 H2O). This preservative is available in powder form. By mixing six parts
of this powder with 100 parts of water, the solution is prepared. The solution is then sprayed
over the surface of timber. This treatment prevents attack from termites. The surface may be
painted to get desired appearance.

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Uses of Timber
Timber is used for the following works:
1. For heavy construction works like columns, trusses, piles.
2. For light construction works like doors, windows, flooring and roofing.
3. For other permanent works like for railway sleepers, fencing poles, electric poles and gates.
4. For temporary works in construction like scaffolding, centering, shoring and strutting,
packing
of materials.
5. For decorative works like showcases and furnitures.
6. For body works of buses, lorries, trains and boats
7. For industrial uses like pulps (used in making papers), card boards, wall papers
8. For making sports goods and musical instruments.
Difference Between Softwood and Hardwood
Softwood and hardwood are two different types of wood. To choose between these two types
of wood one must know the differences between them. The main differences
between Softwood and Hardwood are given below.
Characteristics Softwood Hardwood
Source Softwood is collected from conifer
trees which are evergreen having
needle-shaped leaves. these are
generally gymnosperms.
Hardwood is obtained from
deciduous trees (loses leaves in
autumn). They are basically
angiosperms.
Fibre Less dense, strait fiber is found. In case of hardwood, the fibers are
quite close and dense.
Resin quality It is resinous wood contains good and
regular texture and fragrant smell.
Non-resinous woods have enough
acid.
Weight Lightweight and softer than hardwood. Heavyweight and harder than
softwood.
Colour Softwood is light in color. Normally these are dark colored
woods.
Resistance to fire poorer than hardwood, burn at a high
rate.
better than softwood. Burn at a very
slow rate.
Weather If they are modified or treated then Naturally resistant to whether having

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resistance these may become resistant to whether
having an environmental impact.
a less environmental impact.
Duration Less durable wood. Hardwoods are highly durable and
last for several decades.
Ring structure Distinct annual rings are found. The annual rings are not distinct.
Medullary rays Indistinct medullary rays. Distinct medullary rays.
Growth rate Soft wood trees grow faster than
hardwood trees.
The growth rate of this type of trees
is slower.
Wood branching Creates more branch or shoots. Have fewer shoots.
Tensile and
shear strength
Well tensile and comparatively weaker
shear strength.
Good tensile and shear strength.
Cost Less expensive. More expensive.
Uses Paper pulp, paper, solid wood products,
Woodwares like homes and cabins and
also for furniture.
Generally flooring and furniture.
Also used for papermaking.
Workability Easier to carve. Difficult to curve.
Example Black willow (Salix nigra), Redwood
(Sequoioideae sp).
Sugar maple (Acersaccharum),
Eucalyptus (Eucalyptus globulus).
Characteristics of good timber
1. Appearance: A freshly cut surface of timber should exhibit hard and of shining appearance.
2. Colour: A colour should preferably be dark.
3. Defects: A good timber should be free from series defects such as knots, flaws, shakes etc.
4. Durability: A good timber should be durable and capable of resisting the action of fungi,
insects, chemicals, physical agencies, and mechanical agencies.

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5. Elasticity: The timber returns to its original shape when load causing its deformation is
removed.
6. Fibres: The timber should have straight fibres.
7. Fire resistance: A dense wood offers good resistance to fire.
8. Hardness: A good timber should be hard.
9. Mechanical wear: A good timber should not deteriorate easily due to mechanical wear or
abrasion.
10. Shape: A good timber should be capable of retaining its shape during conversion or seasoning.
11. Smell: A good timber should have sweet smell. Unpleasant smell indicates decayed timber.
12. Sound: A good timber should give a clear ringing sound when struck.
13. Strength: A good timber should be sufficiently strong for working as structural member such as
joist, beam, rafter etc.
14. Structure: The structure should be uniform.
15. Toughness: A good timber should be tough (i.e.) capable of offering resistance to shocks due to
vibration.
16. Water permeability: A good timber should have low water permeability, which is measured by
the quantity of water filtered through unit surface area of specimen of wood.
17. Weathering effects: A good timber should be able to stand reasonably the weathering effects
(dry & wet).
18. Weight: The timber with heavy weight is considered to be sound and strong.
19. Working conditions: Timber should be easily workable. It should not clog the teeth of saw.
Market Forms of Timber
The followings are the various types of market forms of timber.
1.Log
2.Lumber

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3.Bilk
4.Deal
5.Batten
6.Plank
7.Board
8.Scantline
9.Pole
Asbestos
Asbestos is a general name for several varieties of fibrous minerals which are available in
nature. But presently, most of the commercial asbestos produced is ‘chriotile’
[Mg6SiO11(OH)6.H2O].
Properties of Asbestos
1. It is flexible, soft and non-porous.
2. It is fire proof and acid proof material.
3. It is a good insulator of heat and electricity.
4. When it is mixed with cement and water, it retains shape firmly.
5. Its colour is brown or grey.
6. It can be cut into pieces or can be drilled.
7. It possesses high tensile strength in the direction of its fibres.
8. Its specific gravity is 3.10.
Uses of Asbestos
1. Asbestos cement sheets are the cheapest roofing materials.
2. Asbestos cement pipes are used as down take pipes of rain water from the roof.
3. With bitumen it forms good damp proof layer.
4. It is used for preparing fire proof ropes and clothes.
5. It is used as covering material for fuse and electric switch boxes.
6. It is useful for insulating boilers,
Paints
Paints are applied on the surfaces of timber, metals and plastered surfaces as a protective layer and at
the same time to get pleasant appearance. Paints are applied in liquid form and after sometime the
volatile constituent evaporates and hardened coating acts as a protective layer.
Constituents of Paint
The essential constituents of paints are:
1. Base 2. A vehicle 3. A pigment 4. A drier and 5. A thinner.
1. Bases: It is a principal constituent of paint. It also possesses the binding properties. It forms
an opaque coating. Commonly used bases for paints are white lead, red lead, zinc oxide, iron
oxide, titanium white, aluminium powder and lithophone. A lead paint is suitable for painting
iron and steel works, as it sticks to them well. However it is affected by atmosphere action
and hence should not be used as final coat. While zinc forms good base but is costly.

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Lithophone, which is a mixture of zinc sulphate and barytes, is cheap. It gives good appearance
but is affected by day light. Hence it is used for interior works only.
2. Vehicles: The vehicles are the liquid substances which hold the ingredients of a paint in
liquid suspension and allow them to be applied on the surface to be painted. Linseed oil,
Tung oil and Nut oil are used as vehicles in paints. Of the above four oils, linseed oil is very
commonly used vehicles. Boiling makes the oil thicker and darker. Linseed oil reacts with
oxygen and hardens by forming a thin film.
3. Pigment: Pigments give required colour for paints. They are fine particles and have a
reinforcing effect on thin film of the paint. The common pigments for different colours are:
Black—Lamp black, suit and charcoal black.
Red—venedion red, red lead and Indian red.
Brown—burned timber, raw and burned sienna
Green—chrome green, copper sulphate.
Blue—prussian blue and ultra marine
Yellow—ochre and chrome yellow.
4. The Drier: These are the compounds of metal like lead, manganese, cobalt. The function of
a drier is to absorb oxygen from the air and supply it to the vehicle for hardening. The drier
should not be added until the paint is about to be used. The excess drier is harmful because it
destroys elasticity and causes flaking.
5. The Thinner: It is known as solvent also. It makes paint thinner and hence increases the
coverage. It helps in spreading paint uniformly over the surface Terpentine and neptha are
commonly used thinners. After paint applied, thinner evaporates and paint dries.
Properties of an Ideal Paint
1. It should be possible to apply easily and freely.
2. It should dry in reasonable time.
3. It should form hard and durable surface.
4. It should not be harmful to the health of workers.
5. It should not be easily affected by atmosphere.
6. It should possess attractive and pleasing appearance.
7. It should form a thin film of uniform nature i.e., it should not crack.
8. It should possess good spreading power.
9. It should be cheap.
Types of Paints
Depending upon their constituents there are various types of paints. A brief description of some of them
which are commonly used are given below:
1. Oil Paint: These paints are applied in three coats-primer, undercoat and finishing coat. The
presence of dampness while applying the primer adversely affect the life of oil paint. This
paint is cheap and easy to apply.
2. Enamel Paint: It contains white lead, oil, petroleum spirit and resinous material. The surface
provided by it resists acids, alkalies and water very well. It is desirable to apply a coat of
titanium white before the coat of enamel is applied. It can be used both for external and
internal walls.
3. Emulsion Paint: It contains binding materials such as polyvinyl acetate, synthetic resins etc.

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It dries in 1
1
2
to 2 hours and it is easy to apply. It is more durable and can be cleaned with
water. For plastered surfaces, first a coat of cement paint should be applied and then the
emulsion point. Emulsion paint needs sound surfaces.
4. Cement Paint: It is available in powder form. It consists of white cement, pigment and other
additives. It is durable and exhibits excellent decorative appearance. It should be applied on
rough surfaces rather than on smooth surfaces. It is applied in two coats. First coat is applied
on wet surface but free from excess water and allowed to dry for 24 hours. The second coat
is then applied which gives good appearance.
5. Bituminous Paints: This type of paint is manufactured by dissolving asphalt or vegetable
bitumen in oil or petroleum. It is black in colour. It is used for painting iron works under
water.
6. Synthetic Rubber Paint: This paint is prepared from resins. It dries quickly and is little
affected by weather and sunlight. It resists chemical attack well. This paint may be applied
even on fresh concrete. Its cost is moderate and it can be applied easily.
7. Aluminium Paint: It contains finely ground aluminium in spirit or oil varnish. It is visible in
darkness also. The surfaces of iron and steel are protected well with this paint. It is widely
used for painting gas tanks, water pipes and oil tanks.
8. Anti-corrossive Paint: It consists essentially of oil, a strong dier, lead or zinc chrome and
finely ground sand. It is cheap and resists corrossion well. It is black in colour.
Application of Paint
Preparation of surface for application of paint is the most important part in painting. The
surface to be painted should not be oily and it should be from flakes of the old paint. Cracks in
the surface should be filled with putty and then with sand paper. Then primer is applied.
Painting work should be carried out in dry weather. The under coats and first coats must be
allowed to dry before final coat is applied.
Distempers
Distempers are the cheaper variety of paints in which chalk is used as base and water is used as
a carrier. The emulsifying agent which is commonly used is glue or casein. Distempers are
available in powder form or in the form of paste. They are to be mixed with hot water before
use. The surface to be distempered should be thoroughly rubbed and cleaned. The cracks, if any
should be filled by lime putty. The surface should be kept dry for about two months before
applying distemper. Thus a primary coat is applied and is allowed to dry. Distemper is usually
applied in two coats.
Properties of Distemper
1. They are generally light in colour.
2. The coatings are generally thick.
3. They give reflective coating.
4. They are less durable than oil paints but are cheaper.

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Varnish
Varnish is the solution of resins or resinous substances like amber, copal, shellac, gum resin etc. in
solvents like oil, turpentile, alcohol etc. Depending upon the solvents used varnishes are classified as,
oil varnishes, turpentile varnishes, spirit varnishes and water varnishes. The desirable characteristics of
an ideal varnish are
1. It should give glossy surface.
2. Should be durable.
3. It should dry rapidly after application.
4. It should not develop cracks after drying.
It is commonly used on wooden surfaces.
What is Paint, Definition, Properties, & Components of paints.
What is Paint?
A Paint is essentially a coating or covering material applied on metallic or non-metallic surfaces
for decorative or protectivepurposes.
Most commonly they may be a protective as well as decorativefinish.
So, now I think the term “what is paint” will be cleared.
I know that now you will ask about Paint Definition, don’t be worry. You will learn everything
here.
Let’s move on.
Paint Definition:
Paints can be defined as: “A liquid solution of pigment (coloring material) and solvent, which is
applied on different surfaces for decorative or protective reasons.”
OR
It can also be defined as: ” Dispersion of pigment ( coloring substance ) in a suitable drying oil in
the presence of a solvent ( paint thinner ) is known as paint.”
Qualities of Good Paints:
Following are basic qualities of good paints.
(1.) Good Hiding Power:
It should be capable of covering the existing surface of material uniformly and thoroughly.
(2.) Color:
After its use on outer surfaces, they are exposed to the atmosphere.
Due to the exposure to the atmosphere, it may be effected by rain or various types of radiation
from sunlight, which will cause bad effects on its ‘Color.’
Good paints must maintain its color under all these conditions or in any other circumstance.
(3.) Resistance:
Paints should be chemically inert to the atmosphere. This is essential if it has to protect the
underlying surface of a metal.
(4.) Easy Application:
They might have to be used over wide surface areas.

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It is, therefore, necessary that it should be of such a nature that can be spread easily, smoothly,
and uniformly.
(5.) Economical in Cost:
Types of Paint should be selected according to the construction, and its cost should be as low as
possible. Costly paints should not be used in common constructions.
Components of Paint:
Paints are prepared by intimately mixing various components in proper proportions. Following
are essential components of paint.
(1.) The Vehicle:
It is actually an oil which is dried on exposure to air. Hence it is also called a drying oil.
Such oil is unsaturated in composition. On exposure to air, it gets saturated (and hence dries
out). The drying oil or the vehicle has the capacity to keep the pigment and other components
of paint in suspension or solution. These ingredients get deposited in the film, made by the
drying oil on the surface of an object. The most commonly used vehicle or drying oils
are: Linseed oil, dehydrated castor oil, bleached oil, and fish oil. Driers are those substances
which are added to drying oils to accelerate the rate of drying. They act as catalysts in the
oxidation process of the drying oils. The linoleats, resinates, and naphthalenes of metals like
lead, magnesium, and vanadium are commonly used drier.
(2.) Base:
A base is a solid substance that forms the body of the paint.
It consists of a very fine powder of a suitable material such as white lead, red lead, iron oxide,
and titanium oxide, etc.
The base material makes the paints film harder, stronger, elastic, and safe against cracking and
moisture. It makes the paint stable against Ultra Violet Rays as well.
(3.) The Pigments:
It is a coloring material added to the above components in order to impart a desired shade and
color. Pigment is added in a finely powdered state.
In White color paints: White Lead, Titanium White, Lithophone are used as a pigment.
In Red Color: Red Lead, Venetian Red, Chrome Red, Natural Red Oxides of Iron are used as a
pigment. In Yellow Color: Chrome Yellow, Zinc Chromate, Yellow Ochres are used as a pigment.
In Brown Color: Oxides of Iron is used as a pigment.
In Blue Color: Pursian Blue, Paris Blue, Ultramarine, Cobalt Blue are used as a pigment.
(4.) Solvents (Paint Thinner):
They are also called Paint thinner, which reduces the viscosity of the paints to a great extent.
Solvents (paint thinner) or added to paints in order to make its application easy, smooth, and
uniform. Petroleum, spirits, turpentine and coal tar hydrocarbons are some of the commonly
used solvents or paint thinner.
(5.) Extenders:

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They are also called fillers. A Filler is a substance which can be added to paints to increase its
bulk volume without effecting its useful properties.
These materials (Fillers) are necessarily inert towards other components of paint.
Commonly used extenders are: Chalk, gypsum, barite, silica and magnesium silicate.
Chapter No 8
Stones
Stone is a ‘naturally available building material’ which has been used from the early age of
civilization. It is available in the form of rocks, which is cut to required size and shape and used
as building block. It has been used to construct small residential buildings to large palaces and
temples all over the world. Red Fort, Taj Mahal, Vidhan Sabha at Bangalore and several palaces
of medieval age all over India are the famous stone buildings.
Uses of Stones
Stones are used in the following civil engineering constructions:
(i) Stone masonry is used for the construction of foundations, walls, columns and arches.
(ii) Stones are used for flooring.
(iii) Stone slabs are used as damp proof courses, lintels and even as roofing materials.
(iv) Stones with good appearance are used for the face works of buildings. Polished marbles and
granite are commonly used for face works.
(v) Stones are used for paving of roads, footpaths and open spaces round the buildings.
(vi) Stones are also used in the constructions of piers and abutments of bridges, dams and
retaining walls.
(vii) Crushed stones with graved are used to provide base course for roads. When mixed with
tar they form finishing coat.
(viii) Crushed stones are used in the following works also:
(a) As a basic inert material in concrete
(b) For making artificial stones and building blocks
(c) As railway ballast.
Types or Classification of Stones
Stones used for civil engineering works may be classified in the following three ways:
• Geological
• Physical
• Chemical
Geological Classification
Based on their origin of formation stones are classified into three main groups—Igneous,
sedimentary and metamorphic rocks.
(i) Igneous Rocks: These rocks are formed by cooling and solidifying of the rock masses from

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their molten magmatic condition of the material of the earth. Generally igneous rocks are
strong and durable. Granite, trap and basalt are the rocks belonging to this category, Granites
are formed by slow cooling of the lava under thick cover on the top. Hence they have crystalline
surface. The cooling of lava at the top surface of earth results into non-crystalline and glassy
texture. Trap and basalt belong to this category.
(ii) Sedimentary Rocks: Due to weathering action of water, wind and frost existing rocks
disintegrates. The disintegrated material is carried by wind and water; the water being most
powerful medium. Flowing water deposits its suspended materials at some points of obstacles
to its flow. These deposited layers of materials get consolidated under pressure and by heat.
Chemical agents also contribute to the cementing of the deposits. The rocks thus formed are
more uniform, fine grained and compact in their nature. They represent a bedded or stratified
structure in general. Sand stones, lime stones, mud stones etc. belong to this class of rock.
(iii) Metamorphic Rocks: Previously formed igneous and sedimentary rocks under go changes
due to metamorphic action of pressure and internal heat. For example due to metamorphic
action granite becomes greisses, trap and basalt change to schist and laterite, lime stone
changes to marble, sand stone becomes quartzite and mud stone becomes slate.
Physical Classification
Based on the structure, the rocks may be classified as:
• Stratified rocks
• Unstratified rocks
(i) Stratified Rocks: These rocks are having layered structure. They possess planes of
stratification or cleavage. They can be easily split along these planes. Sand stones, lime stones,
slate etc. are the examples of this class of stones.
(ii) Unstratified Rocks: These rocks are not stratified. They possess crystalline and compact
grains. They cannot be split in to thin slab. Granite, trap, marble etc. are the examples of this
type of rocks.
(iii) Foliated Rocks: These rocks have a tendency to split along a definite direction only. The
direction need not be parallel to each other as in case of stratified rocks. This type of structure
is very common in case of metamorphic rocks.
Chemical Classification
On the basis of their chemical composition engineers prefer to classify rocks as:
• Silicious rocks
• Argillaceous rocks and
• Calcareous rocks
(i) Silicious rocks: The main content of these rocks is silica. They are hard and durable.
Examples of such rocks are granite, trap, sand stones etc.
(ii) Argillaceous rocks: The main constituent of these rocks is argil i.e., clay. These stones are
hard and durable but they are brittle. They cannot withstand shock. Slates and laterites are
examples of this type of rocks.

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(iii) Calcareous rocks: The main constituent of these rocks is calcium carbonate. Limestone is a
calcareous rock of sedimentary origin while marble is a calcareous rock of metamorphic origin.
Requirements of Good Building Stones
The following are the requirements of good building stones:
(i) Strength: The stone should be able to resist the load coming on it. Ordinarilly this is not of
primary concern since all stones are having good strength. However in case of large structure, it
may be necessary to check the strength.
(ii) Durability: Stones selected should be capable of resisting adverse effects of natural forces
like wind, rain and heat.
(iii) Hardness: The stone used in floors and pavements should be able to resist abrasive forces
caused by movement of men and materials over them.
(iv) Toughness: Building stones should be tough enough to sustain stresses developed due to
vibrations. The vibrations may be due to the machinery mounted over them or due to the loads
moving over them. The stone aggregates used in the road constructions should be tough.
(v) Specific Gravity: Heavier variety of stones should be used for the construction of dams,
retaining walls, docks and harbours. The specific gravity of good building stone is between 2.4
and 2.8.
(vi) Porosity and Absorption: Building stone should not be porous. If it is porous rain water
enters into the pour and reacts with stone and crumbles it. In higher altitudes, the freezing of
water in pores takes place and it results into the disintegration of the stone.
(vii) Dressing: Giving required shape to the stone is called dressing. It should be easy to dress so
that the cost of dressing is reduced. However the care should be taken so that, this is not be at
the cost of the required strength and the durability.
(viii) Appearance: In case of the stones to be used for face works, where appearance is a
primary requirement, its colour and ability to receive polish is an important factor.
(ix) Seasoning: Good stones should be free from the quarry sap. Laterite stones should not be
used for 6 to 12 months after quarrying. They are allowed to get rid of quarry sap by the action
of nature. This process of removing quarry sap is called seasoning.
(x) Cost: Cost is an important consideration in selecting a building material. Proximity of the
quarry to building site brings down the cost of transportation and hence the cost of stones
comes down. However, it may be noted that not a single stone can satisfy all the requirements
of a good building stones, since one requirement may contradict another. For example,
strength and durability requirement contradicts ease of dressing requirement. Hence it is
necessary that site engineer looks into the properties required for the inteded work and selects
the stone.
Tests on Stones
To acertain the required properties of stones, the following tests can be conducted:

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(i) crushing strength test
(ii) water absorption test
(iii) abrasion test
(iv) impact test
(v) acid test.
(i) Crushing Strength Test: For conducting this test, specimen of size 40 × 40 × 40 mm are
prepared from parent stone. Then the sides are finely dressed and placed in water for 3 days.
The saturated specimen is provided with a layer of plaster of paris on its top and bottom
surfaces to get even surface so that load applied is distributed uniformly. Uniform load
distribution can be obtained satisfactorily by providing a pair of 5 mm thick playwood instead of
using plaster of paris layer also. The specimen so placed in the compression testing machine is
loaded at the rate of 14 N/mm2 per minute. The crushing load is noted. Then crushing strength
is equal to the crushing load divided by the area over which the load is applied. At least three
specimen should be tested and the average should be taken as crushing strength.
(ii) Water Absorption Test: For this test cube specimen weighing about 50 grams are prepared
and the test is carried out in the steps given below:
(a) Note the weight of dry speciment as W1.
(b) Place the specimen in water for 24 hours.
(c) Take out the specimen, wipe out the surface with a piece of cloth and weigh the specimen.
Let its weight be W2.
(d) Suspend the specimen freely in water and weight it. Let its weight be W3.
(e) Place the specimen in boiling water for 5 hours. Then take it out, wipe the surface with
cloth and weigh it. Let this weight be W4. Then,
Percentage absorption by weight =
W2 − W1
W1
x 100 ……… (1)
Percentage absorption by volume =
W2 − W1
W2 − W3
x 100 ……… (2)
Percentage porosity by volume =
W4 − W1
W2 − W3
x 100 ……… (3)
Density =
W1
W2 − W1
……….. (4)
Specific gravity =
W1
W2 − W3
………….. (5)
∴ Saturation coefficient =
Water Absorption
Total Porosity

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=
W2 − W1
W4 − W1
.
(iii) Abrasion Test: This test is carried out on stones which are used as aggregates for road
construction. The test result indicate the suitability of stones against the grinding action
under traffic. Any one of the following test may be conducted to find out the suitability of
aggregates:
(i) Los Angeles abrasion test
(ii) Deval abrasion test
(iii) Dorry’s abrasion test.
However Los Angeles abrasion test is preferred since these test results are having good
correlation with the performance of the pavements.
The Los Angeles apparatus [Fig. 1.1] consists of a hollow cylinder 0.7 m inside diameter and
0.5 m long with both ends closed. It is mounted on a frame so that it can be rotated about
horizontal axis. IS code has standardised the test procedure for different gradation of specimen.
Along with specified weight of specimen a specified number of cast iron balls of 48 mm
diameter are placed in the cylinder
Then the cylinder is rotated at a speed of 30 to 33 rpm for specified number of times (500 to
1000). Then the aggregate is removed and sieved on 1.7 mm. IS sieve. The weight of aggregate
passing is found. Then Los Angeles value is found as
=
Weight of aggregate passing through sieve
Original weight
x 100.
The following values are recommended for road works:
For bituminous mixes – 30%
For base course – 50%

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(iv) Impact Test: The resistance of stones to impact is found by conducting tests in impacting
testing machine (Fig. 1.2). It consists of a frame with guides in which a metal hammer weighing
13.5 to 15 kg can freely fall from a height of 380 mm.
Aggregates of size 10 mm to 12.5 mm are filled in cylinder in 3 equal layers; each layer being
tamped 25 times. The same is then transferred to the cup and again tamped 25 times. The
hammer is then allowed to fall freely on the specimen 15 times. The specimen is then sieved
through 2.36 mm sieve. Then,
Impact value =
W2
W1
where W2 = weight of fines
W1 = original weight.
The recommended impact values for various works are:
(i) for wearing course > 30%
(ii) for bituminous mechadam > 35%
(iii) for water bound mechadam > 40%
(v) Acid Test: This test is normally carried out on sand stones to check the presence of calcium
carbonate, which weakens the weather resisting quality. In this test, a sample of stone weighing
about 50 to 100 gm is taken and kept in a solution of one per cent hydrochloric acid for seven
days. The solution is agitated at intervals. A good building stone maintains its sharp edges and
keeps its surface intact. If edges are broken and powder is formed on the surface, it indicates
the presence of calcium carbonate. Such stones will have poor weather resistance.
Properties of Stones
The following properties of the stones should be looked into before selecting them for

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engineering works:
(i) Structure: The structure of the stone may be stratified (layered) or unstratified. Structured
stones should be easily dressed and suitable for super structure. Unstratified stones are hard
and difficult to dress. They are preferred for the foundation works.
(ii) Texture: Fine grained stones with homogeneous distribution look attractive and hence they
are used for carving. Such stones are usually strong and durable.
(iii) Density: Denser stones are stronger. Light weight stones are weak. Hence stones with
specific gravity less than 2.4 are considered unsuitable for buildings.
(iv) Appearance: A stone with uniform and attractive colour is durable, if grains are compact.
Marble and granite get very good appearance, when polished. Hence they are used for face
works in buildings.
(v) Strength: Strength is an important property to be looked into before selecting stone as
building block. Indian standard code recommends, a minimum crushing strength of 3.5 N/mm2
for any building block. Table 1.1 shows the crushing strength of various stones. Due to non-
uniformity of the material, usually a factor of safety of 10 is used to find the permissible stress
in a stone. Hence even laterite can be used safely for a single storey building, because in such
structures expected load can hardly give a stress of 0.15 N/mm2. However, in stone masonry
buildings care should be taken to check the stresses when the beams (Concentrated Loads) are
placed on laterite wall.
Table 1.1. Crushing strength of common building stones
Name of Stone Crushing Strength in
N/mm2
Trap
Basalt
Granite
Slate
Marble
Sand stone
Lime stone
Laterite
300 to 350
153 to 189
104 to 140
70 to 210
72
65
55
1.8 to 3.2
(vi) Hardness: It is an important property to be considered when stone is used for flooring and
pavement. Coefficient of hardness is to be found by conducting test on standard specimen in
Dory’s testing machine. For road works coefficient of hardness should be at least 17. For
building works stones with coefficient of hardness less than 14 should not be used.
(vii) Percentage wear: It is measured by attrition test. It is an important property to be
considered in selecting aggregate for road works and railway ballast. A good stone should not
show wear of more than 2%.
(viii) Porosity and Absorption: All stones have pores and hence absorb water. The reaction of
water with material of stone cause disintegration. Absorption test is specified as percentage of
water absorbed by the stone when it is immersed under water for 24 hours. For a good stone it

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should be as small as possible and in no case more than 5.
(ix) Weathering: Rain and wind cause loss of good appearance of stones. Hence stones with
good weather resistance should be used for face works.
(x) Toughness: The resistance to impact is called toughness. It is determined by impact test.
Stones with toughness index more than 19 are preferred for road works. Toughness index 13 to
19 are considered as medium tough and stones with toughness index less than 13 are poor
stones.
(xi) Resistance to Fire: Sand stones resist fire better. Argillaceous materials, though poor in
strength, are good in resisting fire.
(xii) Ease in Dressing: Cost of dressing contributes to cost of stone masonry to a great extent.
Dressing is easy in stones with lesser strength. Hence an engineer should look into sufficient
strength rather than high strength while selecting stones for building works.
(xiii) Seasoning: The stones obtained from quarry contain moisture in the pores. The strength
of the stone improves if this moisture is removed before using the stone. The process of
removing moisture from pores is called seasoning. The best way of seasoning is to allow it to
the action of nature for 6 to 12 months. This is very much required in the case of laterite
stones.
Quarrying and important stone quarries in Pakistan
Pakistan contains major deposits of export quality marble, granite and onyx in wide range of
colors, shades and patterns. All provinces in Pakistan have ornamental stone deposits.
Balochistan has rich confirmed deposits of marble and granite in Khuzdar, Loralai, Lasbela and
Chaghi districts. In NWFP, Malakand, Mardan, Hazara, Peshawar and Kohat divisions are high-
potential areas where quarrying and mining is already taking place. Mohmand, Khyber, Bajaur,
Orakzai, Khurram Agencies in FATA extract considerable quantities of marble. Punjab
ornamental stone quarries/mines operate in Khushab and Mianwali. Nagarparkar in Province of
Sindh boasts of gold colored stone which is highly priced in the global market. Some of the
varieties are as under:
• Granite, • Verona, • Champagne, • Boticina, • Fancy, • King Gold, • Indus Gold, • Black &
Gold, • Black Zebra, • Red Zebra, • Rosa Brona, • Burma Teak, • Trevira, • Badal, • Ziarat White,
• Nowshera Pink, • Light Green Onyx, • Medium Green Onyx, • Dark & Multi Green Onyx etc.
In most of the countries, processing is done on highly sophisticated machinery for quality
production. In Pakistan very few units are using these machines while rest of the industry uses
locally fabricated machinery. The primitive mining techniques existing in Pakistan do not allow
extraction of standard blocks. Major factors for the decline in Pakistan’s Marble Industry are
lack of quality production and inconsistent supply of raw material. The extraction in Pakistan
mainly comprise boring of holes in the bedrock, filled with explosives to blast the block,
resulting not only in high wastage but also in smaller sized stone, substantially reducing the
price. Standard quarry wastage in the world is taken at 50% of the gross produce; however, in

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Pakistan this reaches upto 73%. There are thus bright prospects of setting up joint ventures in
the Marble Sector of Pakistan.
Model quarries / mine projects are being set up according to the best international practices for
extracting stone and employing latest technology. Marble Cities are being established in the
vicinity of mines all over Pakistan, incorporating:
DETERIORATION OF STONES:
Deterioration of stone is the process of their breaking or their decay. Atmospheric agencies
such as: rain, temperature, wind, frost, and living organisms, etc are responsible for their
deterioration and these agencies bring about physical and chemical changes in the stones and
disintegrate them. So, the stones which can resist the effect of all these agencies are said to be
durable. Some preservative materials which are used to preserve the stones from deterioration
are: coal tar, linseed oil, barium hydrate solution, alum soap solution (mixture of alum and soft
soap). By applying some of above preservative materials, stones can be preserved from the
decaying.
Common Building Stones
The following are the some of commonly used stones:
(i) Basalt and trap, (ii) Granite, (iii) Sand stone, (iv) Slate, (v) Laterite
(vi) Marble, (vii) Gneiss, (viii) Quartzite.
Their qualities and uses are explained below:
(i) Basalt and Trap: The structure is medium to fine grained and compact. Their colour varies
from dark gray to black. Fractures and joints are common. Their weight varies from 18 kN/m3 to
29 kN/m3. The compressive strength varies from 200 to 350 N/mm2. These are igneous rocks.
They are used as road metals, aggregates for concrete. They are also used for rubble masonry
works for bridge piers, river walls and dams. They are used as pavement.
(ii) Granite: Granites are also igneous rocks. The colour varies from light gray to pink. The
structure is crystalline, fine to coarse grained. They take polish well. They are hard durable.
Specific gravity is from 2.6 to 2.7 and compressive strength is 100 to 250 N/mm2. They are used
primarily for bridge piers, river walls, and for dams. They are used as kerbs and pedestals. The
use of granite for monumental and institutional buildings is common. Polished granites are
used as table tops, cladding for columns and wall. They are used as coarse aggregates in
concrete.
(iii) Sand stone: These are sedimentary rocks, and hence stratified. They consist of quartz and
feldspar. They are found in various colours like white, grey, red, buff, brown, yellow and even
dark gray. The specific gravity varies from 1.85 to 2.7 and compressive strength varies from 20
to 170 N/mm2. Its porosity varies from 5 to 25 per cent. Weathering of rocks renders it
unsuitable as building stone. It is desirable to use sand stones with silica cement for heavy
structures, if necessary. They are used for masonry work, for dams, bridge piers and river walls.
(iv) Slate: These are metamorphic rocks. They are composed of quartz, mica and clay minerals.
The structure is fine grained. They split along the planes of original bedding easily. The colour

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varies from dark gray, greenish gray, purple gray to black. The specific gravity is 2.6 to 2.7.
Compressive strength varies from 100 to 200 N/mm2. They are used as roofing tiles, slabs,
pavements etc.
(v) Laterite: It is a metamorphic rock. It is having porous and sponges structure. It contains high
percentage of iron oxide. Its colour may be brownish, red, yellow, brown and grey. Its specific
gravity is 1.85 and compressive strength varies from 1.9 to 2.3 N/mm2. It can be easily quarried
in blocks. With seasoning it gains strength. When used as building stone, its outer surface
should be plastered.
(vi) Marble: This is a metamorphic rock. It can take good polish. It is available in different
pleasing colours like white and pink. Its specific gravity is 2.65 and compressive strength is 70–
75 N/ mm2. It is used for facing and ornamental works. It is used for columns, flooring, steps
etc.
(vii) Gneiss: It is a metamorphic rock. It is having fine to coarse grains. Alternative dark and
white bands are common. Light grey, pink, purple, greenish gray and dark grey coloured
varieties are available. These stones are not preferred because of deleterious constituents
present in it. They may be used in minor constructions. However hard varieties may be used for
buildings. The specific gravity varies from 2.5 to 3.0 and crushing strength varies from 50 to 200
N/mm2.
(viii) Quartzite: Quartzites are metamorphic rocks. The structure is fine to coarse grained and
often granular and branded. They are available in different colours like white, gray, yellowish.
Quartz is the chief constituent with feldspar and mica in small quantities. The specific gravity
varies from 2.55 to 2.65. Crushing strength varies from 50 to 300 N/mm2. They are used as
building blocks and slabs. They are also used as aggregates for concrete.
Chapter No 9
Bituminous Materials
Ashalt, bitumen and tar are referred as bituminous materials, which are essentially
hydrocarbon materials. The asphalt is a mixture of inert mineral matter lime alumina, lime,
silica etc. and a hydrocarbon known as asphaltic bitumen. In some places like Trinidad and
Bermudez, asphalt is available in nature at a depth of 3 to 60 metres. It is known as natural
asphalt. Common variety used all over the world is residual asphalt, which is obtained by
fractional distillation of crude petroleum oil. Bitumen is the binding material which is present in
asphalt. It is a hydrocarbon. It is obtained by partial distillation of crude oil. It contains 87 per
cent carbon, 11 per cent hydrogen and 2 per cent oxygen.
Tar is obtained in the distructive distillation of coal, wood or other organic materials. When coal
or wood is heated to redness in an closed chamber, it yields volatile product and residue coke.
After separating and cooling volatile product gives tar.
Comparison between asphalt, bitumen and tar is presented in Table 5.1.

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Table 5.1. Comparison between asphalt, bitumen and tar
S.
No.
Property Asphalt Bitumen Tar
1.
2.
3.
4.
5.
6.
7.
8.
Colour
Carbon content
State
Effect on
heating
Setting time
Adhesive
power
Resistance to
acid
Use
Blackish brown
Low
Solid or semisolid
Burns with a smoke
flame and becomes
plastic
Less
Less
More
As damp proof course, for
paints, as roofing felt and
for road works.
Dark with slight
reddish tinge
Moderate
Solid
Melts
Less
More
More
As damp proof
course
and as roofing
felt.
Deep dark
High
Viscous liquid
Becomes more
fluid.
More
Most
Less
For preserving
timber.
OR
Bituminous materials or asphalts are extensively used for roadway construction, primarily
because of their excellent binding characteristics and water proofing properties and relatively
low cost. Bituminous materials consist of bitumen which is a black or dark coloured solid or
viscous cementitious substances consists chiefly high molecular weight hydrocarbons derived
from distillation of petroleum or natural asphalt, has adhesive properties, and is soluble in
carbon disulphide. Tars are residues from the destructive distillation of organic substances such
as coal, wood, or petroleum and are temperature sensitive than bitumen. Bitumen will be
dissolved in petroleum oils where unlike tar.
Composition of Bitumen
Materials in bituminous family are:
1) Tar:
Coal tar is a brown or dark black liquid of high viscosity, which smells of naphthalene and
aromatic hydrocarbons. Being flammable, coal tar is sometime used for heating or to fire
boilers. It can be used in coal tar soap, and is used in medicated shampoo to kill and repel head
lice, and as a treatment for dandruff.
Depending upon its source of origin, TAR is classified as:
2) Coal Tar:
It is the liquid by-product of the distillation of coal to make coke. The gaseous by-product of this
process is commonly known as town gas. It is used for coating of wooden poles and sleepers,
iron poles.
3) Wood Tar:

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It is obtained by the distillation of resinous wood. Wood tar contains creosote and as such has
strong preservative properties. Search for "resin" in the above search box.
4) Mineral Tar:
It is obtained by the distillation of bituminous shale.
5) Coal Tar Pitch:
It is the residue of the direct distillation of crude tar produced by the high temperature
carbonization of coal. It is used as a water proofing compound in masonry, steel and timber
structure. It is also used for water proofing concrete structures.
Chemical Composition of Bitumen:
Molecular weight wise, bitumen is a mixture of about 300 - 2000 chemical components, with an
average of around 500 - 700. Elementally, it is around 95% carbon and hydrogen (± 87% carbon
and ± 8% hydrogen), and up to 5% sulfur, 1% nitrogen, 1% oxygen and 2000ppm metals.
Bitumens are composed mainly of highly condensed polycyclic aromatic hydrocarbons. They
also contain several elements, a number of which are toxic.
Chemical Components in bitumen are:
1. Asphaltenes
2. Resinous components (polar aromatics)
3. Non-polar aromatics (naphtene aromatics) and
4. Saturates
Importance of Bituminous Material:
Bitumen is an essential component of any pavement and is used widely throughout the world.
It can be termed as the building block of the pavements without which all the pavement
materials would behave independently and thus will be deemed useless. Almost ninety percent
of bitumen is used in road construction. It is usually available in dark colors ranging from brown
to black. The main purpose of bitumen in flexible pavements is to strongly bind and hold the
other pavement components together and provide a smooth and leveled surface for the
moving vehicles. Bitumen is a naturally occurring material and is found in large quantities in the
solid or semi solid forms of petroleum. It is also manufactured artificially in vast amounts
globally.
Bitumen mixed with some other materials has always been used as a sealant and adhesive
material over the ages. It was also widely used in the water proofing of boats and ships as it is
insoluble in water. Highest applications of bitumen are found in the construction filed for the
construction of roads, airports etc, in the hydraulic field for the construction of water tanks,
dams, bridges etc, is also used in battery making, tyre making and for the thermal and acoustic
insulation purposes.
Types of Bitumen:
Depending upon the temperature and other factors various types of bitumen are found and
used throughout the world.
Cutback Bitumen:

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Cut-back bitumens are those which are prepared with the addition of a volatile to reduce the
thickness of the binder.
Fluxed Bitumen:
Fluxed bitumens are that bitumen which are prepared by the addition of relatively non volatile
oils to reduce the viscosity of the binder.
Modified Bitumen:
Modified bituminous binder are those whose properties such as cohesive strength, adhesive
property, elasticity or viscosity have been modified by the use of one or combined chemical
agents.
Asphalt:
Asphalt is a mixture of aggregates both fine (sand and filler) and coarse (stone) and a
bituminous binder. It typically contains approximately 4-7% of bitumen. Asphalt is primarily
used in road construction and its properties depend upon the type, size and amount of
aggregate used in the mixture, all of which can be adjusted to provide the required properties
for the desired application.
Owing to their high thermoplastic properties, bitumen is always recommended to be used
wearing all protective gadgets. Even a small drop of highly heated bitumen can cause severe
burns to exposed body parts. Therefore, high care is needed in the handling of any type of
bitumen to avoid any mishaps during site work.
Types of Bituminous Mixtures
Types of Bituminous Mixtures used in Pavement Construction
A bituminous mixture is a combination of bituminous materials (as binders), properly graded
aggregates and additives. Since tar is rarely used in bituminous mixtures in recent years and
asphalt is the predominant binder material used, the term “asphalt mixture” is now more
commonly used to denote a combination of asphalt materials, aggregates and additives.
Asphalt mixtures used in pavement applications are usually classified by
(1) Their methods of production, or
(2) Their composition and characteristics.
Classification by Method of Production
Hot-mix asphalt (HMA)
Hot-mix asphalt (HMA) is produced in a hot asphalt mixing plant (or hot-mix plant) by mixing a
properly controlled amount of aggregate with a properly controlled amount of asphalt at an
elevated temperature. The mixing temperature has to be sufficiently high such that the asphalt
is fluidic enough for proper mixing with and coating the aggregate, but not too high as to avoid
excessive aging of the asphalt. A HMA mixture must be laid and compacted when the mixture is
still sufficiently hot so as to have proper workability. HMA mixtures are the most commonly
used paving material in surface and binder courses in asphalt pavements.
Cold-laid plant mix

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Cold-laid plant mix is produced in an asphalt mixing plant by mixing a controlled amount of
aggregate with a controlled amount of liquid asphalt without the application of heat. It is laid
and compacted at ambient temperature.
Mixed-in-place or road mix
Mixed-in-place or road mix is produced by mixing the aggregates with the asphalt binders in
proper proportions on the road surface by means of special road mixing equipment. A medium
setting (MS) asphalt emulsion is usually used for open-graded mixtures while a slow setting (SS)
asphalt emulsion is usually used for dense-graded mixtures.
Penetration macadam
Penetration macadam is produced by a construction procedure in which layers of coarse and
uniform size aggregate are spread on the road and rolled, and sprayed with appropriate
amounts of asphalt to penetrate the aggregate. The asphalt material used may be hot asphalt
cement or a rapid setting (RS) asphalt emulsion.
Classification by Composition and Characteristics
Dense-graded HMA mixtures, which use a dense-graded aggregate and have a relatively low air
voids after placement and compaction, are commonly used as surface and binder courses in
asphalt pavements. The term Asphalt Concrete is commonly used to refer to a high-quality,
dense-graded HMA mixture.
A dense graded HMA mixture with maximum aggregate size of greater than 25 mm (1 in.) is
called a large stone dense-grade HMA mix. A dense-grade HMA mix with 100% of the aggregate
particles passing the 9.5 mm (3/8 in.) sieve is called a sand mix.
Open-graded asphalt mixtures, which use an open-graded aggregate and have a relatively high
air void after placement and compaction, are used where high water permeability is desirable.
Two primary types of open-graded mixes are
(1) open-graded base mix and
(2) open-graded friction course (OGFC).
Open-graded base mixes
Open-graded base mixes are used to provide a strong base for an asphalt pavement as well as
rapid drainage for subsurface water. Open-graded base mixes usually use a relatively larger size
aggregate that contains very little or no fines. Due to the lower aggregate surface area, these
mixes have relatively lower asphalt content than that of a dense-graded HMA mix. Open-
graded base mixes can be produced either hot or cold in an asphalt plant.
Open-graded friction courses (OGFC)
Open-graded friction courses (OGFC) are placed on top of surface courses to improve skid
resistance and to reduce hydroplaning of the pavement surface. OGFC mixtures use aggregates
with a small proportion of fines to produce high air voids and good drainage characteristics.
Even though the voids content is higher, the asphalt film thickness is usually greater than that
for a dense-graded HMA, and thus a typical OGFC mixture has about the same or higher asphalt
content than that of a dense-graded HMA. A typical OGFC uses an aggregate of ½ in. (12.5mm)
maximum size, and is placed at a thickness of ¾ in. (19 mm). An OGFC mixture is produced in a

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hot-mix plant in the same way as a dense-graded HMA mixture. Crumb rubber modified asphalt
has been used in OGFC mixtures in recent years to improve their performance and durability.
Due to the higher viscosity of the crumb rubber modified binder, thicker film thickness can be
used. This results in a higher binder content and thus better durability for the crumb rubber
modified OGFC mixtures.
Stone Matrix Asphalt (SMA), which was originally developed in Europe, was a special asphalt
mixture of improved rutting resistance and increased durability. SMA mixtures are designed to
have a high coarse aggregate content (typically 70–80%), a high binder content (typically over
6%) and high filler content (typically about 10%). Asphalts modified with polymers and/or fibers
are typically used. The improved rutting resistance of the SMA mixture is attributed to the fact
that it carries the load through the coarse aggregate matrix (or the stone matrix), as compared
with a dense-graded HMA, which carries the load through the fine aggregate. The use of
polymer and/or fiber modified asphalts, which have increased viscosity, and the use of high
filler content, which increases the stiffness of the binder, allow the SMA mixtures to have a
higher binder film thickness and higher binder content without the problem of draindown of
asphalt during construction. The increased durability of the SMA mixtures can be attributed to
the higher binder film thickness and the higher binder content. SMA mixtures require the use of
strong and durable aggregates with a relatively lower L.A. Abrasion Loss. SMA mixtures can be
produced in a hot-mix plant in a similar way as a dense-grade HMA mixture. The main
disadvantage of using a SMA as compared with a dense-grade HMA is its relatively higher cost
due to the requirement for the use of higher quality aggregates, polymer, fibers and fillers.
Bitumen types
Bitumen has a number of applications but its use for construction and maintenance of roads
either directly or through asphalt accounts for nearly 90% of all demand. Key bitumen types for
road applications including paving grades, cutback bitumen, and bitumen emulsions. Hard,
oxidized, and blown grades and mastic asphalt are used for paints, sealants, adhesives,
enamels, waterproofing, electrical products, flooring materials, back carpet tiles, land and
marine pipe coatings and numerous other non-road applications. Polymer-modified bitumen
(PMB) is a recent innovation that is finding growing application in both paving and non-road
applications. Although there are numerous non-road applications for bitumen, they consume
small volumes and road paving is the primary application. As a result, infrastructure cuts have
significantly impacted global bitumen demand.
There are different types of bitumen available with different properties, specifications and uses
based on requirements of consuming industry.
The specification of bitumen also shows variation with the safety, solubility, physical properties,
and the durability.
To understand the performance of the bitumen when it is on service, the design of physical
properties of the material is highly essential. The standard testing methods are carried out to
grade bitumen.

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The bitumen types regarding its generation source bitumen can be classified into three
categories: natural, petroleum asphalts, coal tar pitches:
1– Natural bitumen or native asphalts are a class of bitumen which have been naturally
produced due to climate conditions in the course of time, and are used without the need to be
processed in distillation ways; they are very varied regarding their composition and properties.
2– Coal tar Pitches are hard black substances which are formed as the result of coal tar
distillation. Their new broken surface is shiny and when they are heated they, along with a fast
decrease in viscosity, melt, and their melting point depends on the production process.
3– Petroleum Asphalts are the bitumen which is derived from petroleum. These are solid and
semi-solid bitumen which is directly produced through distillation from petroleum or by
additional operations such as air blowing. Compared with the other types, they are more
commonly used and have more applications.
Bitumen types regarding their application regarding their applications, bitumen can be divided
into two groups: road construction or thin bitumen, and building bitumen and (roof insulator)
or hard bitumen. About 90% of the produced bitumen is used in road construction activities
and 10 % of it is used for insulation applications. In Iran, the main part of bitumen is used in the
road construction activities and by the municipalities for coating the streets. Road construction
bitumen is usually classified according to its penetration. The penetration rate of bitumen
material represents its strength and hardness which is defined as the number of penetration
unit (one tenth millimeter) of one vertical standard needle in one bitumen sample, in the
certain time and weight on the needle and temperature. The penetration rate of bitumen is
usually measured 25-degree centigrade with 100-gram weight and in 5 seconds. Road
construction bitumen made in Iran are “60 to 70” and ’85 to 100”. The numbers represent the
range of bitumen penetration rate. Bitumen is hydrocarbon substance which is black to dark
brown and quite solvable in carbon-sulfur. It is solid in normal environment temperature but in
increased temperature, it first becomes a paste and then liquid. It has two important
properties, impenetrable against water and adhesiveness which makes it an important material
for the application.
Bitumen is usually acquired from petroleum distillation. Such kind of bitumen is called
petroleum asphalt or distillery bitumen. Petroleum bitumen is the product of two stages of
petroleum distillation in a distillation tower. In the first stage of distillation, light materials such
as gasoline and propane are separated from the raw oil. This process is done in the pressure
close to atmospheric pressure. In second stage heavy compounds such as diesel oil and
kerosene are extracted. This process is done at a pressure close to vacuum pressure. Finally, a
mixture of solid bits called asphaltene remains which are floated in a grease-like fluid called
Malton.
Some kinds of bitumen are acquired from nature by gradual changing of petroleum and the
evaporation of its evaporating materials by passing many years, such kind of bitumen is called
natural bitumen, and it is more lasting than petroleum asphalts. Such bitumen may be found in
nature in pure form (lake bitumen) or extracted from mines (mineral bitumen).

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1) Blown Bitumen
Blown asphalt comes from hot air blown to pure bitumen in the last stage of refining. In this
process, hot air having 200-300-degree centigrade temperature is blown to bitumen container
with porous tubes. In this process, hydrogen atoms in bitumen hydrocarbon are combined with
oxygen in the air and by forming water, polymerization happens. Compared with pure bitumen,
blown bitumen has a low penetration rate and a high softness point. This kind of bitumen is
used in making roof sheets, automobile battery, and coating.
2) Mixed or Solution Bitumen
Mixed bitumen is a term used to refer to a mixture of bitumen and a suitable liquid (for
example kerosene or gasoline). This bitumen in normal environment temperature is liquid or is
changed to liquid with a little heat. Mixed bitumen is used in different kinds of macadam and
coating asphalts. The speed of its clotting or hardening depends on the kind of liquid. For
example, because of the high speed of gasoline evaporation, bitumen solved in gasoline
hardens faster. This bitumen is called rapid clotting (RC) bitumen. The bitumen solved in
kerosene is called mild clotting (MC) bitumen and those solved in gas oil or fuel oil is called slow
clotting (SC). Liquid bitumen is classified according to their viscosity rate.
3) Emulsion Bitumen
Emulsion bitumen is produced by mixing bitumen, water, and an emulsion making material. The
emulsion making material is usually alkali salt of an organic acid or ammonium salt which
charges bitumen particles. So the bitumen particles expel each other because of their induction
charges and float in the form of balls having one hundredth to one thousandth millimeter
diameter. The use of such kind of bitumen decreases environment pollution and as oil or
flammable solvents aren’t used the danger of flaming during transportation is decreased.
Other bitumen types
Other bitumen types are as follow:
Viscosity graded bitumen
Bitumen is graded based on absolute viscosity at 60 ºC or a kinematic viscosity at 135 ºC. The SI
physical unit of dynamic viscosity is Poise and kinematic viscosity is expressed in Centistokes.
Specifications for viscosity graded bitumen normally give the nominal viscosity prefixed by a V,
e.g. V10.
Performance graded bitumen
PG is the latest standard of the day. This relatively new method classified bitumen is based on
varying temperatures. It is a fully scientific method studying the mechanical specifications of
bitumen. In this method, a temperature range is defined for bitumen and the consumer can
easily choose the desired product.
Having installed SHRP systems, RABIT (RAHA BITUMEN) Company is capable of selling bitumen
to its customers based on PG method.
Today, a PG is defined for polymer modified bitumen and pure bitumen based on
environmental conditions and temperature. A wider PG range means higher resistance and
more favorable specifications.

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Penetration graded bitumen
Graded Bitumen is classified by the depth to which a standard needle will penetrate under
specified test conditions. This “pen” test classification is used to indicate the hardness of
bitumen, lower penetration indicating a harder bitumen. Specifications for penetration graded
bitumens normally state the penetration range for a grade, e.g. 50/70. Other tests are used to
classify the bitumen for specification purposes, such as softening point, solubility, flash point
etc.
Oxidized grade bitumen
Passing air through bitumen at elevated temperature can be used to alter its physical
properties for certain commercial applications. The degree of oxidation can range from very
small, often referred to as air-rectification, or semi-blowing, which only slightly modifies the
bitumen properties, through to “full” blowing, whereby the properties of the bitumen are
significantly different to penetration grade bitumen. Nomenclature and grading for the oxidized
bitumen products are based on a combination of the temperature at which the bitumen
reaches certain “softness” when being heated up as expressed by the ring and ball softening
point test, and the penetration value. Eurobitume has published a paper clarifying the criteria
used to differentiate between air-rectified bitumen and oxidized bitumen.
Polymer Modified Bitumen (PMD):
Polymer modified bitumen (PMB) are mixtures produced from: bitumen polymers in which the
polymers change the visco-elastic behavior of the bitumen and thus make this binder more
suitable for different stresses.
The most commonly used polymer for bitumen modification is styrene–butadiene–styrene
(SBS) followed by other polymers such as styrene–butadiene–rubber (SBR), ethylene-vinyl-
acetate (EVA), and polyethylene. SBS block copolymers are classified as elastomers that
increase the elasticity of bitumen. Although polymer modified bitumen costs higher than pure
bitumen, they are considered to be more economical because of economic benefits of lower
costs of road repairs.
Properties of Bitumen and Bituminous Materials

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Following are the properties of Bitumen
1. Adhesion
2. Resistance to Water
3. Hardness
4. Viscosity and Flow
5. Softening Point
6. Ductility
7. Specific Gravity
8. Durability
9. Versatility
10. Economical
11. Strength
Adhesion:
The adhesive property of bitumen binds together all the components without bringing about
any positive or negative changes in their properties. Bitumen has the ability to adhere to a solid

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surface in a fluid state depending on the nature of the surface. The presence of water on the
surface will prevent adhesion.
Resistance to Water:
Bitumen is insoluble in water and can serve as an effective sealant Bitumen is water resistant.
Under some conditions water may be absorbed by minute quantities of inorganic salts in the
bitumen or filler in it.
Hardness:
To measure the hardness of bitumen, the penetration test is conducted, which measures the
depth of penetration in tenths of mm. of a weighted needle in bitumen after a given time, at a
known temperature. Commonly a weight of 100 gm is applied for 5 secs at a temperature of 77
°F. The penetration is a measure of hardness. Typical results are 10 for hard coating asphalt, 15
to 40 for roofing asphalt and up to 100 or more for water proofing bitumen.
The grades with penetrations greater than 40 are mostly used in road construction and
occasionally in industrial applications. The grades with penetrations less than 40 are used
exclusively in industrial applications. In hot climate lower grades such as 60/70 is used.
Viscosity and Flow:
The viscous or flow properties of bitumen are of importance both at high temperature during
processing and application and at low temperature to which bitumen is subjected during
service. The flow properties of bitumens vary considerably with temperature and stress
conditions. Deterioration, or loss of the desirable properties of bitumen, takes the form of
hardening. Resultantly, decrease in adhesive and flow properties and an increase in the
softening point temperature and coefficient of thermal expansion.

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Softening point:
This property makes us to know whether given bitumen can be used at the particular place i.e.
softening point value should be higher than pavement temperature otherwise bitumen present
in the layer get soften and come out.
Softening point is the temperature at which a steel ball falls a known distance through the
bitumen when the test assembly is heated at a known rate. Usually the test consists of a (3/8)
in dia. steel ball, weight 3.5 gm, which is allowed to sink through a (5/8) in dia, (1/4) in thick disk
of bitumen in a brass ring. The whole assembly is heated at a rate of 9 °F per min. Typical values
would be 240 °F for coating grade asphalts, 140 °F to 220 °F for roofing asphalt and down to
115 °F for bituminous water proofing material.
Ductility:
Ductility test is conducted to determine the amount bitumen will stretch at temperature below
its softening point. A briquette having a cross sectional area of 1 in2 is placed in a tester at 77
°F. Ductility values ranges from 0 to over 150 depending on the type of bitumen.
Presence of ductility means the formation of the film and coating would be proper.
Specific Gravity
Specific gravity of a binder does not influence its behaviour. But all the same, its value is
needed in mix design. The property is determined at 27º C.
Durability:
Bitumen durability refers to the long-term resistance to oxidative hardening of the Material in
the field. Although, in-service, all bitumens harden with time through reaction.
With oxygen in the air, excessive rates of hardening (poor durability) can lead to premature
binder embrittlement and surfacing failure resulting in cracking and chip loss. Bitumen lives
upto twenty years if maintained properly throughout the pavement life.
Versatility:
Due to versatility property of Bitumen it is relatively easy to use it in many applications because
of its thermoplastic property. It can be spread easily along the underlying pavement layers as it
liquefies when heated making the job easier and hardens in a solid mass when cooled.
Economical:
It is available in cheaper rates almost all over the world which makes it feasible and affordable
in many applications.
Strength:
Though the coarse aggregates are the main load bearing component in a pavement, bitumen or
asphalt also play a vital role in distributing the traffic loads to the layers beneath.
General Properties of Bitumen
 Most bitumens are colloidal in nature.
 Bitumen are thermoplastics.
 They have no specific melting, boiling or freezing point.
 Bitumens are insoluble in water.

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 They are highly impermeable to the passage of water.
 They are generally hydrophobic. They are chemically inert.
 Bitumen oxidises slowly.
Uses of Bitumen in Civil Engineering
Following is the list of applications of bitumen in real life:
1. Hydraulics & erosion control Catchment areas, basins
2. Dam grouting
3. Dam linings, protection
4. Dyke protection
5. Ditch linings
6. Drainage gutters, structures
7. Embankment protection
8. Groynes
9. Jetties
10. Levee protection
11. Mattresses for levee & bank protection
12. Membrane linings, waterproofing
13. Reservoir linings
14. Revetments
15. Sand dune stabilization
16. Sewage lagoons, oxidation ponds
17. Swimming pools
18. Waste ponds
19. Water barriers
20. Backed felts
Tests Applied on Bitumen in Roads for Quality Construction
Experience in using bitumen in engineering projects has led to the adoption of certain test
procedures that are indicative of the characteristics that identify adequate performance levels.
Some of the tests have evolved with the development of the industry and are empirical
methods. Consequently, it is essential that they are carried out in strict compliance with the
recommended procedures if they are to be accurate measurements of the bitumen's
properties.
1. Penetration Test
2. Flash Point Test
3. Solubility Test
4. Ductility Test
5. Viscosity Test

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1. Penetration Test on Bitumen
The penetration test is one of the oldest and most commonly used tests on asphalt cements or
residues from distillation of asphalt cutbacks or emulsions. The standardized procedure for this
test can be found in ASTM D5 [ASTM, 2001]. It is an empirical test that measures the
consistency (hardness) of an asphalt at a specified test condition.
Procedure of Penetration Test on Bitumen:
In the standard test condition, a standard needle of a total load of 100 g is applied to the
surface of an asphalt or Liquid bitumen sample at a temperature of 25 °C for 5 seconds. The
amount of penetration of the needle at the end of 5 seconds is measured in units of 0.1 mm (or
penetration unit). A softer asphalt will have a higher penetration, while a harder asphalt will
have a lower penetration. Other test conditions that have been used include
1. 0 °C, 200 g, 60 sec., and
2. 46 °C, 50 g, 5 sec.
The penetration test can be used to designate grades of asphalt cement, and to measure
changes in hardness due to age hardening or changes in temperature.
2. Flash Point Test on asphalt:
The flash point test determines the temperature to which an asphalt can be safely heated in the
presence of an open flame. The test is performed by heating an asphalt sample in an open cup
at a specified rate and determining the temperature at which a small flame passing over the
surface of the cup will cause the vapors from the asphalt sample temporarily to ignite or flash.
The commonly used flash point test methods include
The Cleveland Open Cup (ASTM D92)
Tag Open Cup (ASTM D1310).
The Cleveland Open-Cup method is used on asphalt cements or asphalts with relatively higher
flash points, while the Tag Open-Cup method is used on cutback asphalts or asphalts with flash
points of less than 79 °C. Minimum flash point requirements are included in the specifications
for asphalt cements for safety reasons. Flash point tests can also be used to detect
contaminating materialssuch as gasoline or kerosine in an asphalt cement. Contamination of an
asphalt cement by such materials can be indicated by a substantial drop in flash point.
When the flash point test is used to detect contaminating materials, the Pensky-Martens Closed
Tester method (ASTM D93), which tends to give more indicative results, is normally used. In
recent years, the flash point test results have been related to the hardening potential of
asphalt. An asphalt with a high flash point is more likely to have a lower hardening potential in
the field.
3. Solubility Test on asphalt bitumen
Asphalt consists primarily of bitumens, which are high-molecular-weight hydrocarbons soluble
in carbon disulfide. The bitumen content of a bituminous material is measured by means of its
solubility in carbon disulfide.
Procedure for Solubility test on Bitumen

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In the standard test for bitumen content (ASTM D4), a small sample of about 2 g of the asphalt
is dissolved in 100 ml of carbon disulfide and the solution is filtered through a filtering mat in a
filtering crucible. The material retained on the filter is then dried and weighed, and used to
calculate the bitumen content as a percentage of the weight of the original asphalt. Due to the
extreme flammability of carbon disulfide, solubility in trichloroethylene, rather than solubility in
carbon disulfide, is usually used in asphalt cement specifications. The standard solubility test
using trichloroethylene is designated as ASTM D 2042.
The solubility test is used to detect contamination in asphalt cement. Specifications for asphalt
cements normally require a minimum solubility in trichloroethylene of 99.0 percent.
Unfortunately, trichloroethylene has been identified as a carcinogen and contributing to the
depletion of the earth’s ozone layer. The use of trichloroethylene will most likely be banned in
the near future. There is a need to use a less hazardous and non-chlorinated solvent for this
purpose. Results of several investigations have indicated that the solvent n-Propyl Bromide
appears to be a feasible alternative to trichloroethylene for use in this application.
4. Ductility Test on Asphalt
The ductility test (ASTM D113) measures the distance a standard asphalt sample will stretch
without breaking under a standard testing condition (5 cm/min at 25 °C). It is generally
considered that an asphalt with a very low ductility will have poor adhesive properties and thus
poor performance in service. Specifications for asphalt cements normally contain requirements
for minimum ductility.
5. Viscosity Tests on Bitumen Asphalt
The viscosity test measures the viscosity of an asphalt. Both the viscosity test and the
penetration test measure the consistency of an asphalt at some specified temperatures and are
used to designate grades of asphalts. The advantage of using the viscosity test as compared
with the penetration test is that the viscosity test measures a fundamental physical property
rather than an empirical value. Viscosity is defined as the ratio between the applied shear stress
and induced shear rate of a fluid.
Shear Rate = Shear Stress / Viscosity
When shear rate is expressed in units of 1/sec. and shear stress in units of Pascal, viscosity will
be in units of Pascal-seconds. One Pascal-second is equal to 10 Poises. The lower the viscosity of
an asphalt, the faster the asphalt will flow under the same stress. For a Newtonian fluid, the
relationship between shear stress and shear rate is linear, and thus the viscosity is constant at
different shear rates or shear stress. However, for a non-Newtonian fluid, the relationship
between shear stress and shear rate is not linear, and thus the apparent viscosity will change as
the shear rate or shear stress changes.
Asphalts tend to behave as slightly non-Newtonian fluids, especially at lower temperatures.
When different methods are used to measure the viscosity of an asphalt, the test results might
be significantly different, since the different methods might be measuring the viscosity at
different shear rates. It is thus very important to indicate the test method used when viscosity
results are presented.

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The most commonly used viscosity test on asphalt cements is the Absolute Viscosity Test by
Vacuum Capillary Viscometer (ASTM D2171).
The standard test temperature is 60 °C. The absolute viscosity test measures the viscosity in
units of Poise. The viscosity at 60 °C represents the viscosity of the asphalt at the maximum
temperature a pavement is likely to experience in most parts of the U.S. When the viscosity of
an asphalt at a higher temperature (such as 135 °C) is to be determined, the most commonly-
used test is the Kinematic Viscosity Test (ASTM D2170), which measures the kinematic viscosity
in units of Stokes or centi-Stokes. Kinematic viscosity is defined as: When viscosity is in units of
Poise and density in units of g/cm3 the kinematic viscosity will be in units of Stokes. To convert
from kinematic viscosity (in units of Stokes) to absolute viscosity (in units of Poises), one simply
multiplies the number of Stokes by the density in units of g/cm3.
ASPHALTS
Asphalt and bitumens form an inter-related group or materials that have wide application in
construction engineering. You’ll know different types of Asphalt here.
The term asphalt is used somewhat differently in different countries. Thus in the USA, by
Asphalt it is understood a solid or semisolid product in which the dominating constituents are
the bitumens.
This definition covers both the natural asphalt rock and the byproduct of a similar composition
obtained during refining of crude petroleum.
In Europe and elsewhere, however, the term asphalt is generally restricted to a naturally
occurring rock which contains bitumens in good abundance.
It is not used for artificial mixtures or products.
The term bitumen, however, is universally regarded a complex mixture of hydrocarbons.
Types of Asphalt.

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1. Native Asphalt.
Pure asphalts occur in nature in the form of solid or semi-solid deposits in certain parts of the
world. The best known are the Lake Asphalt deposits of Venezuela. Sometime the asphalt rock
may contain other mineral impurities.
2. Asphalt Rock.
It is a type of limestone converted to asphalt rock. This has happened at places where natural
bitumens have entered the crevices of limestone rock and changed it to an asphaltic
composition. The asphalt rock is used at places of occurrence for road paving and road making.
3. Asphaltites.
These are actually asphalt like in composition and have low softening points (200° F or so).
Some asphaltites are used considerably in electrical storage batteries, thermo-plastic molded
goods, mastic flooring and pipeline coatings.
Countries producing natural asphalt and asphalt rock are: Trinidad, Albama, France, Germany,
Italy, United States of America, Iraq and Syria.
Uses of Asphalts.
Asphalts are used, generally in combination with other materials, in many engineering fields.
Some examples are given below:
1. ELECTRICAL USES.
High-grade asphalts are used in electrical industry on mixing with wood tar, pitch, rubber, and
resin. The battery containers are its best examples.
2. ROADWAY CONSTRUCTION.
Asphaltic bitumens are characterized by a set of useful properties such as: resistance to
weather, water proofness, binding capacity and ability to provide a flexible surface.
For these qualities, they are used extensively in highway construction both in the road
foundations and as surface materials.
Types of Asphalt Mixture used in Roads.
Three types of the asphaltic mixture used in roads are:
1. Rolled Asphalt,
2. Mastic Asphalt,
3. Compressed Rock Asphalt.
The rolled asphalt is used for paving only. The mastic asphalt is rich in bitumens. It is used
mixed with aggregates when it forms a water proof and plastic material which can be given any
desired shape while in hot condition.
3. ASPHALTIC PAINTS.
Bituminous asphalts are used as essential ingredients in certain paints. Such paints are
especially useful for damp walls and over concrete structures.
4. ASPHALT CONCRETE.
Some asphalt is refined to specifications that give it excellent binding properties. It is called
asphalt cement, and when mixed with fine and coarse aggregates, it gives asphalt concrete.

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It is in this form that the asphalt is generally used in highway and airport paving, where it gives
the pavement desired flexibility and strength at the same time.
Chapter No 10
Construction aspects of engineering projects
Top 10 Most Impressive Civil Engineering Projects of All Time
Whether engineering is an art, a skill, or just a regular profession, history has shown that
through engineering, mankind is continuously surpassing expectations and our natural
limitations. There are many great civil engineering projects all over the world, but here we
countdown the ones that transcend time and continue to impress and inspire new generations.
1. Great Pyramid of Giza
The Great Pyramid of Giza is the oldest of the Seven Wonders of the Ancient World. It is the
oldest and largest of the three pyramids in the Giza pyramid complex, bordering El Giza, Egypt.
It is believed that the pyramid was built as a tomb for the fourth Dynasty Egyptian pharaoh,
Khufu and was constructed over a twenty-year period. It is believed by many that Khufu’s vizier,
Hemon, or Hemiunu, is the architect who designed the pyramid. It remained the tallest man-
made structure in the world for over 3,800 years. Also, experts estimate that it would cost
around $5 billion to build a replica today.
So, over the centuries, we have seen many great civil engineering projects that have become
historic landmarks and icons. Engineering has created some of the biggest structures in the
world, and are a showcase of our ability to construct a unique vision. Every engineer will have a
different opinion on the most impressive creations, but these ten are widely considered the
greatest. However, there are many other engineering creations that have impressed the world,
such as the Millau viaduct, which is the tallest cable-stayed road bridge in the world. Also, as
recently as 2015, the Shanghai Tower skyscraper in China, was completed and it’s now the
second-tallest building in the world. The future is bright for engineering; as advanced
technology will pave the way for even more stunning creations.

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2. Great Wall of China
With a history of more than 2,000 years, many sections of the Great Wall of China are in ruins,
but it is still one of the greatest wonders of the world, and an immensely popular tourist
attraction. The Great Wall stretches from Dandong in the east to Lop lake in the west. The
entire wall with all its different branches, measures out to be 13, 171 miles. It isn’t possible to
know exactly how much the wall would have cost to build, but modern calculation say it would
be somewhere between $13billion and $65 billion.
3. Aqueduct of Segovia
More precisely known as the aqueduct bridge, this Roman aqueduct is one of the most
significant and best-preserved ancient monuments left on the Iberian Peninsula. It is located in
Spain and is the symbol of Segovia, and has been kept in excellent condition over the centuries.
It provided water to Segovia until the 19th century.
4. Brooklyn Bridge

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The Brooklyn Bridge is one of the oldest bridges in the United States, and it’s both a suspension
and cable-stayed bridge. Completed in 1883, it connects the boroughs of Manhattan and
Brooklyn by spanning the East River. The bridge was initially designed by German engineer,
John August Roebling, but due to his death, he was replaced by his son, Washington Roebling
who took charge of the project. It cost $15.5 million to build. Since it opened, it has become a
historic icon of New York City, and was designated a historic landmark in 1964.
5. Panama Canal
Panama Canal is a 48-mile waterway in Panama that connects the Atlantic Ocean with the
Pacific Ocean. The canal consists of several artificial lakes and channels, and two locks at either
end. The canal cuts across the Isthmus of Panama and is crucial for international maritime
trade. Work on the canal began in 1881, and it was finally opened in 1914, costing the
Americans $375 million.

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6. Hoover Dam
Constructed during the Great Depression, the Hoover Dam is a concrete arch-gravity dam in the
Black Canyon of the Colorado River. The construction of the Hoover Dam claimed hundreds of
workers’ lives, and impounds Lake Mead, the largest reservoir in the United States. The dam is
named after President Herbert Hoover, and it took five years to build and cost around $49
million.
7. Golden Gate Bridge
The Golden Gate Bridge is often considered one of the most beautiful bridges in the world. This
$27 million project is a suspension bridge that spans the golden gate strait, connecting the city
of San Francisco to Marin County. It opened in 1937 and was until 1964, the longest suspension
bridge in the world. The bridge is one of the most recognised and influential symbols of the
United States.
8. English Channel Tunnel

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The channel tunnel links Folkestone, Kent in the UK with Coquilles, Pas-de-Calais in northern
France. Despite Japan’s Seikan tunnel being longer overall, the channel tunnel has the longest
undersea portion of any tunnel in the world. It carries high-speed Eurostar passenger trains, as
well as Eurotunnel shuttle for road vehicles, which is the largest transport system in the world.
When it opened in 1994, the final cost came in at an astounding £9 billion, making it the most
expensive construction project ever at the time.
9. Burj Khalifa
As the tallest structure in the world, standing at 829.8 meters, Burj Khalifa in Dubai was
designed as the centrepiece for a new development called Downtown Dubai. The building was
named in honour of the ruler of Dubai and president of the United States Arab Emirates. It was
designed by Skidmore, Owings and Merrill (SOM), and the design is inspired by the patterns and
structures in Islamic architecture. The structure cost $1.5 billion to build. At the time of its
opening in 2010, it had the highest observational deck in the world. The building has even
featured in popular culture, as it can be seen in 2016 film, ‘Independence Day: Resurgence’.
Burj Khalifa has broken numerous other records, including building with most floors at 211 and
it has received immensely positive reception.

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10. Qingdao Haiwan Bridge
Qingdao Haiwan Bridge, also known as Jiaozuo Bay Bridge, is the world’s longest bridge over
water at 41.58 km (25.84 miles). It connects the city of Qingdao in Eastern China with the
Huangdao suburbs, across the water of Jiaozuo Bay. The bridge was designed by the Shandong
Gaosu Group, and it took four years to build, with at least 10,000 workers employed for its
construction. Also, its construction costs equate to 900 million in British pounds.
Chapter No 11
Layout techniques with special reference to buildings
Layout of Building
Layout of a building or a structure shows the plan of its foundation on the ground surface
according to its drawings, so that excavation can be carried out exactly where required and
position and orientation of the building is exactly specified. It is set out according to foundation
plan drawings and specifications provided by the engineer or an architect. In order to
understand layout or setting out of a building we must understand some of the technical terms
related to this job which are described below.

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BASELINE
A baseline is a straight reference line with respect to which corners of the building are located
on the ground. It may be outer boundary of a road or curb or boundary of the area or simply a
line joining any two points.
HORIZONTAL CONTROLS
Horizontal controls are the points that have known co-ordinates with respect to a specific point.
These points are then used to locate other points such as corners of a layout using various
techniques. There should be plenty of control points so that each point of foundation plan can
be located precisely on the ground.
VERTICAL CONTROLS

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In order that design points on the works can be positioned at their correct levels, vertical
control points of known elevation relative to some specified vertical datum are established. In
practice, 20 mm diameter steel bolts and 100 mm long, with known reduce levels driven into
existing steps, ledges, footpaths etc. may serve as vertical controls.
BATTERBOARDS AND OFFSET PEGS
Once points specifying the layout are located on ground pegs are driven in the ground at that
spot. Once excavations for foundations begin, the corner pegs will be lost. To avoid these extra
pegs called offset pegs are used. Batter boards are normally erected near each offset peg and
are used to relocate the points after the excavation has been done.
LAYING OUT A RECTANGULAR BUILDING SITE
Starting from a baseline (line AB in Figure 4-1) that is parallel to construction, establish the
maximum outer borders (AB, CD, AC, BD) of the building area.

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Suppose we know the co-ordinates (x, y) of the points X with respect to point A then we can
locate it by measuring their x distance along line AB and y distance along line AC and BD
respectively to locate them. These two points can be joined to make line XX. To locate point G
and H, straight line is set out using 3-4-5 triangle rule and distance XG and XH which is known is
marked on those lines. After the four corners (X, X, G. and H) have been located, drive stakes at
each corner. Dimensions are determined accurately during each step.
LAYING OUT AN IRREGULAR BUILDING SITE
Where the outline of the building is other than a rectangle, the procedure in establishing each
point is the same as defined for laying out a simple rectangle. However, more points have to be
positioned, and the final proving of the work is more likely to disclose a small error. When the
building is an irregular shape, it is sensible to first lay out a large rectangle which will includes
the entire building or the greater part of it. This is shown in Figure 4-2 as HOPQ When this is
established, the remaining portion of the layout will consist of small rectangles, each of which
can be laid out and shown separately. These rectangles are shown as LMNP ABCQ, DEFG, and
IJKO in Figure

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EXTENDING LINES
Since the corner pegs of the building are to be removed during excavation these points are
transferred outside that periphery by extending lines and driving pegs in the ground. The
following procedure applies to a simple layout as shown in Figure 4-4, page 4-4, and must be
amended to apply to different or
more complex layout problems:
Step 1: After locating and dipping stakes A and B. erect batter boards 1, 2, 3, and 4. Extend a
chalk line (X) from batter board 1 to batter board 3, over stakes A and B.
Step 2: After locating and dipping stake C, erect batter boards 5 and Extend chalk line Y from
batter board 2 over stakes A and C to batter board 6.
Step 3: After locating and dipping stake D, erect batter boards 7 and Extend chalk line Z from
batter board 5 to batter board 7, over stakes C and D.
Step 4: Extend line O from batter board 8 to batter board 4, over stakes D and B.
Where foundation walls are wide at the bottom and extend beyond the outside dimensions of
the building, the excavation must be larger than the laid-out size. To lay out dimensions of this
excavation, measure out as far as required from the building line on each batter board and
stretch lines between these points, outside the first layout.
Chapter No 12
Brick Masonry:

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Brick Masonry Definition
Brick masonry is a highly durable form of construction. It is built by placing bricks in mortar in a
systematic manner to construct solid mass that withstand exerted loads. There are several
types of bricks and number of mortars which can be used to construct brick masonry.
The bond in brick masonry, which adheres bricks together, is produced by filling joints between
bricks with suitable mortar. Special cautions shall be practiced while mortar is mixed and placed
since it greatly affects the performance and durability of masonry structure.
Types of Brick Masonry Work
1. Brick Work in Mud
 The mud is used to fill up various joints brick masonry work.
 Thickness of the mortar joint is 12 mm.
 it is the cheapest type of brick masonry
 Employed for construction of walls with maximum height of 4 m.
Fig. 1: Brick work in mud
2. Brick Work in Cement
This type of brick masonry is construction by laying bricks in cement mortar rather than mud
which is used in brick work in mud. There are three major classes of brick work in cement which
are summarized in Table 1.
Table 1 Different classes of brick work in cement and their descriptions
Classes Descriptions
First Class
Cement of lime mortar is used,
The surface and edges of bricks are sharp,
And the thickness of mortar joints doesn’t exceed
10mm

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Second Class
Ground moulded bricks are used,
Bricks are rough and shape is slightly irregular,
The thickness of mortar joint is 12 mm.
Third Class
1. Bricks are not hard ,rough surface with distorted shape,
2. Used for temporary structures,
3. Used in places where rainfall is not heavy.
Fig. 2: Brick work in cement
Types of Bricks
There are different types of brick used in the construction of brick masonry which include:
1. Common Burnt Clay Bricks
2. Concrete Bricks
3. Sand Lime Bricks (Calcium Silicate Bricks)
4. Fly ash Clay Bricks
5. Engineering Bricks
6. Other Brick Types include bullnose, channel, coping, cownose and hollow bricks.

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Fig. 3: Types of masonry bricks
Brick Masonry Construction
Materials and Equipment Used in Brick Masonry Construction
1. Mortar Mix or Mason Mix Bricks
2. Tape measure
3. hammer
4. Hose, level, or theodolite
5. Trowel Level
6. Wheelbarrow
7. Goggles
8. Jointer
9. And other equipment according to project ans personal preferences
Brick Masonry Construction Preparations
1. Check the level of the ground using level, theodolite or transparent hose level.
2. Set the layout of the structure.
Fig. 4: Setting out layout of masonry structure

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3. Trace of building axis and wall alignment using gypsum powder, chalk, or similar,
marking the trenches for foundation.
4. After that, install foundation wall, cure foundation for minimum two days before
beginning of brick masonry construction.
5. Distribute bricks in several stacks along project site to cut time and effort later.
6. Wet bricks few hours prior to the work. Not only does this avoid absorbing too much
water from mortar but also improve adherence of bricks and mortar.
Brick Masonry Construction Procedure
Initially, mix the mortar with water and blend it until a smooth and plastic mortar is produced.
Fig. 5: Mortar Preparation
1. After that, place the mortar on foundation line evenly using trowel (25mm thickness and
one brick wide is recommended for laid mortar).
2. Then, lay the first course of stretcher bricks in the mortar. Start with second brick, apply
mortar to the head joint end of each brick, after that shove the bricks into place firmly
so that the mortar is squeezed out of all side of the joints.
Fig. 6: laying bricks
3. Utilize a level to examine the course for correct height. ensure that bricks are plumb and
level.

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Fig. 7: Plumb line of brick masonry
Fig. 8: Checking level of brick masonry
4. Place another mortar line alongside the first course, then begin laying the second
course.
5. Use the two half bricks to begin the second to ensure that the first two courses are
staggered for structural purposes.
6. To finish the second course of the lead, lay three header bricks and make sure that they
are plumb and level.
7. The third and fifth courses consists of stretchers similar to the first course. The fourth
course begins with single header, followed by stretchers. Use the level to make sure that
the lead is true on each course. Lastly, this pattern of brick laying is used till the target
height is reached.

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Points Considered in Supervising Brick Masonry Constructions
The following points should be observed in the construction of brick masonry:
 Use good quality bricks.
 Ensure that brick courses are perfectly horizontal.
 Verticality of the wall should be ensured by frequently checking with plumb-bob.
 Whenever work is stopped brick masonry should be left with toothed end.
 Use of brick bats should be avoided.
 Raising walls by more than 1.5 m in one day shall be prevented.
 Raise face joints to a depth of 12 to 20mm so as to be used as a key for plastering or
pointing.
 Brick masonry should be regularly cured for 2 weeks.
 The thickness of mortar joints shall be 10 mm both horizontally and vertically.
Fig. 9: Brick bat
TERMS USED IN BRICK MASONRY WORK
1. COURSE:
A horizontal layer of similar bricks or stones that are bonded with mortar is known ascourse.
2. QUOINS:
Quoins are the stones used for the corners of the walls.
3. BED:
The horizontal layer of mortar where brick or stone units are laid is known as bed.

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4. BACK:
The inner surface of a brick wall which is not exposed termed as back. The material forming
back is known as backing.
5. FACE:
The exterior surface of a brick wall which is exposed to weather termed as face. The material
used in the face of the wall is known as facing.
6. HEARTING:
The interior portion of a wall between the facing and backing is termed as hearting.
7. JOINT:
The junction of two or more bricks or stones is called joint. There are eight types of mortar
joints-
1. Concave
2. Vee
3. Flush
4. Raked
5. Extruded
6. Beaded
7. Struck
8. Weathered

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8. HEADER:
The shorter side or end face of a brick that is exposed is termed as header.
9. STRETCHER:
The longer narrow side or face of a brick that is exposed is termed as stretcher.
10. FROG:
An indentation or depression on the top face of the brick made with the object of forming a key
for the mortar is termed as frog. The depth of frog is usually between 10-20 mm.
11. BOND:
This is the method of arranging bricks so that the individual units are tied together.
12. ARRIS:
The sharp corner edges of brick are known as arris.
13. SPALLS:
Spalls are the chips of stones used for filling the interstices in stone masonry.
14. BAT:
The portion of bricks cut across the width is termed as bat.

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Three Quarter Bat: It is the form of brick bat having its length equal to three quarter of length
of a full brick.
Half Bat: If the length of the bat is equal to half the length of the full bricks.
Bevelled Bat: A brick bat is called bevelled bat when its width has bevelled.
15. CLOSER:
Closer is the small piece of brick cut lengthwise in such a manner that its one long face remains
uncut and used at the end of masonry wall to maintain bond pattern.
16. QUEEN CLOSER:
When a brick is cut along its length, making it two equal pieces then it is called queen closer.
17: QUEEN CLOSER QUARTER:
When a queen closer is cut in to two equal pieces then it is called as queen closer quarter.
18. KING CLOSER:
King closer are the portion of a brick obtained by cutting off the triangular piece between
center of one end and the center of one side.
19. BEVELLED CLOSER:
Similar to king closer with the only difference that the whole length of the brick bevelled for
maintaining the half width at one end and full width at the other.

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20. MITRED CLOSER:
It is a brick whose one end is cut splayed or mitred for full width. The angle of splay vary from
45 to 60 degree.
21. ROWLOCK:
The head is visible and the long narrow sides are on bottom and top.
22. ROWLOCK STRETCHER:
When the thinner stretcher sides are on bottom and top faces on the sides.
23. SAILOR:
The heads are on top and bottom and the stretcher faces are on the side. Mostly used for
decoration.
24. SOLDIER:
The stretcher side is visible and the heads are at the bottom and top. It is usually used for
decoration.
25. BUTTERING:
Placing of mortar in on masonry block with trowel is termed as buttering.

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Brick masonry
Brick masonry is built with bricks bonded together with mortar. For temporary sheds mud
mortar may be used but for all permanent buildings lime or cement mortars are used.
The most commonly used types of bonds in brick masonry are:
1. Stretcher bond
2. Header bond
3. English bond and
4. Flemish bond
Other Types of bonds are:
1. Facing bond
2. Dutch bond
3. English cross bond
4. Brick on edge bond
5. Raking bond
6. Zigzag bond
7. Garden wall bond
1. Stretcher bond
Longer narrow face of the brick is called as stretcher as shown in the elevation of figure below.
Stretcher bond, also called as running bond, is created when bricks are laid with only their
stretchers showing, overlapping midway with the courses of bricks below and above.
Stretcher bond in the brick is the simplest repeating pattern. But the limitation of stretcher
bond is that it cannot make effective bonding with adjacent bricks in full width thick brick walls.
They are suitably used only for one-half brick thick walls such as for the construction half brick
thick partition wall.
Walls constructed with stretcher bonds are not stable enough to stand alone in case of longer
span and height. Thus they Then need supporting structure such as brick masonry columns at
regular intervals.
Stretcher bonds are commonly used in the steel or reinforced concrete framed structures as
the outer facing. These are also used as the outer facing of cavity walls. Other common
applications of such walls are the boundary walls, gardens etc.

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Fig-1: Stretcher Bond
2. Header bond
Header is the shorter square face of the brick which measures 9cm x 9cm. Header bond is also
known as heading bond. In header bonds, all bricks in each course are placed as headers on the
faces of the walls. While Stretcher bond is used for the construction of walls of half brick
thickness whereas header bond is used for the construction of walls with full brick thickness
which measures 18cm. In header bonds, the overlap is kept equal to half width of the brick. To
achieve this, three quarter brick bats are used in alternate courses as quoins.
Fig-2: Header Bond

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Fig-3: Header Bond Isometric View
3. English Bond
English bond in brick masonry has one course of stretcher only and a course of header above it,
i.e. it has two alternating courses of stretchers and headers. Headers are laid centered on the
stretchers in course below and each alternate row is vertically aligned.
To break the continuity of vertical joints, quoin closer is used in the beginning and end of a wall
after first header. A quoin close is a brick cut lengthwise into two halves and used at corners in
brick walls.
Fig-4: English Bond

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Fig-4: English Bond – Isometric View
4. Flemish Bond
For the breaking of vertical joints in the successive courses, closers are inserted in alternate
courses next to the quoin header. In walls having their thickness equal to odd number of half
bricks, bats are essentially used to achieve the bond.
Flemish bond, also known as Dutch bond, is created by laying alternate headers and stretchers
in a single course. The next course of brick is laid such that header lies in the middle of the
stretcher in the course below, i.e. the alternate headers of each course are centered on the
stretcher of course below. Every alternate course of Flemish bond starts with header at the
corner.
The thickness of Flemish bond is minimum one full brick. The disadvantage of using Flemish
bond is that construction of Flemish bond is difficult and requires greater skill to lay it properly
as all vertical mortar joints need to be aligned vertically for best effects. For the breaking of
vertical joints in the successive courses, closers are inserted in alternate courses next to the
quoin header. In walls having their thickness equal to odd number of half bricks, bats are used
to achieve the bond.
Flemish bonds have better appearance but are weaker than English bonds for load bearing wall
construction. Thus, if the pointing has to be done for brick masonry walls, then Flemish bond
may be used for better aesthetic view. If the walls have to be plastered, then it is better to use
English bond.

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Fig-5: Flemish Bond

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Fig-6: Flemish Bond Front Appearance
Flemish bonds are classified as:
1. Single Flemish Bond
2. Double Flemish Bond
Single Flemish bond is a combination of English bond and Flemish bond. In this type of
construction, the front exposed surface of wall consists of Flemish bond and the back surface of
the wall consists of English bond in each course. Minimum thickness required for single Flemish
bond is one and a half brick thickness. The main purpose of using single Flemish bond is to
provide greater aesthetic appearance on the front surface with required strength in the
brickwork with English bond.
Double Flemish Bond has the same appearance both in the front and back elevations, i.e. each
course consists of alternate header and stretcher. This type of bonding is comparatively weaker
than English bond.
CONSTRUCTION TOOLS AND THEIR USES
1. HOE:

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A hoe is a tool used to digging soil and to place cement mortar, concrete in head pan.
2. PICK AXE:
It is a hand tool with hard metal head and wooden handle. This tool is used to excavate the soil.
It is more suitable for hard soil which is quite difficult to dig with spade or hoe.
3. SPADE:
A spade is tool contains metal plate at the end of long wooden handle. It is used to dig the soil
for foundation trenches etc.
4. DIGGING BAR:

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A digging bar is a long straight solid metal rod with pin shape at the bottom used to dig the hard
surfaces of ground.
5. MEASURING BOX:
Measuring box is used to measure the quantity of cement, sand and aggregates used for
making concrete mix. The volume of measuring box is generally 1 cum feet which makes it easy
to measure concrete ratio. The general dimensions of measuring box are 300 x 300 x 400 mm.
6. HEAD PAN:
Head pan is commonly used in construction sites made of iron or plastic. It is used to lift
excavated soil or cement or concrete to the working site.
7. MASONRY TROWEL:

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The masonry trowel is used in brick work or stone work spreading, leveling and shaping mortar
or concrete. It is made up of steel and wooden handle is provided for holding. The ends of
trowel may be pointed or bull nosed.
8. FLOAT:
It is made up of wood contains handle on its top and smooth surface on its bottom. Float is
used to give a smooth finish to the plastered area.
9. WHEEL BARROW:
A wheel barrow is a small hand propelled vehicle with one wheel designed to be pushed by a
single person using two handle at the rear. It is used to transport bulk weight of materials like
cement, sand, mortar, concrete etc.
10. PLUMB BOB:

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A plumb bob is a weight with pointed tip at the bottom, suspended from a string and used as a
vertical reference line or plumb line. It is used to check verticality of structures. It is also used in
surveying to level the instrument position.
11. CONCRETE MIXER:
A concrete mixer is a device that homogeneously mixes cement, aggregates such as sand or
gravels and water to form concrete. A typical concrete mixer uses a revolving drum to mix the
components.
12. CROWBAR:
Crow bars are commonly used to open nailed wooden crates, remove nails, or pry apart board.
13. BRICK HAMMER:
Brick hammer has one flat traditional face and a short or long chisel shaped blade. It is used to
cut the bricks and also used to push the bricks if they come out from the course line.

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14. CHISEL:
A chisel is a tool that has a long metal blade with a sharp edge at the end and a handle which is
struck with a hammer or mallet. It is generally used in wood work and must be useful to
remove the concrete bumps or excess concrete in harden surface.
15. LINE AND PINS:
A line pin is a metal rod usually with a pointed, leaf shaped blade and and a flat button head.
Lines are typically found in pairs as they are commonly used as anchor points for a brick line. It
is used to level the alignment of bricks course while brick laying.
16. MEASURING TAP:
It is a common measuring tool consist of a ribbon of clothe, plastic, fiber glass or metal strip
with linear measurement marking. It is used to check the thickness, length, widths of masonry
walls, foundation beds, excavated trenches etc.
17. RUBBER BOOTS:

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Safety rubber boots are required to protect legs may have damaged due to contact with
chemical materials like cement or physical accidents during the construction work.
18. GLOVES:
Gloves are required to prevent the hands from direct contact with cement, paints etc. and to
avoid injury while using machines, tools etc. Gloves made from lather, cotton, synthetic, nitrile,
latex, PVC or combinations of these.
19. HAND SAW:
Hand saw is used to cut wood materials like doors, windows etc.
20. LADDER:

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A ladder is a vertical or inclined set of rugs or steps. It is also required in construction works to
check the slab work, to transport material to the higher floor, to paint the walls etc.
21. TILE CUTTER:
Tile cutters are used to cut the tiles to a required shape and size. Sometimes normal size of tiles
is larger than the size required at the corners where the floor meets the wall in that case tile
cutter is useful.
22. PUTTY KNIFE:
Putty knife is used to level the putty finishing and also used to reduce the thickness of finish
when it is more thick.
23. DRILL MACHINE:

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Drill machine is used to make holes in the walls, slabs, doors, window frames etc.
24. JACK PLANE:
Jack plane is used in the wooden work to smoothen the surface of doors, windows etc.
25. MASON SQUARE:
Mason square is used to achieve perfect right angle at the corner of masonry wall. It is L
shaped. First course is laid properly using mason square then based on first, remaining layers of
bricks are set out.
26. MEASURING WHEEL:

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Measuring wheel is used to measure the distances or lengths. It contains a wheel of known
diameter which record the number of complete revolutions from which distance can be
measured. It makes the work easier.
27. EARTH RAMMER:
An earth rammer is a hand tool consist of big square shaped block with handle. Sometimes it is
also called tamper. It is used in construction industries to compress or compact earth or soil.
The earth rammer creates a solid, compacted layer of earth by compressing the soil repeatedly
with its weight.
28. SAFETY GLASSES:
Safety glasses should be used to protect the eye from dust, chemical action of materials etc.
29. SAFETY HELMET:
The safety helmet is regarded one of the basic safety device required for workers in several
industrial and construction related sectors in addition to industries likes mining's, petroleum,
refineries and so on. If any material for structure may fall from height during construction work,
it protects the head from injury or any fatal accident.

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30. SCRATCHER:
Plastering of a surface is carried out layer wise, minimum two layer are necessary for plastering.
To provide a good bond between the old and new layer, old layer is scratched with the help of
tool called scratcher.
31. SAND SCREEN MACHINE:
The sand screen machine is used to screen the sand or fine aggregate before mixing it with
concrete. It should remove the impurities and coarse particles from sand.
32. SPIRIT LEVEL:
A spirit level is an instrument designed to indicate whether a surface is horizontal or vertical. It
is made up of wood or hard plastic with bubble tube in the middle which is partially filled with
alcohol so the air bubble is formed in it. It is used in brick masonry, plastering, flooring and tile
work to check the horizontal level of surface. The surface is leveled if the air bubble settles at
the middle of the tube.

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33. POLISHER:
A polisher is a device used to smoothen the rough surfaces of tiles, marble, wood works etc.
The smoothening makes them shine and the process is called polishing.
34. BUMP CUTTER:
A bump cutter is a tool used to leveled the fresh concrete surfaces likes concrete floors,
foundations, pavement etc. This is also called screed.
35. CIRCULAR SAW:
Circular saw is used to cut wood boards, frames etc. It is used when accurate cutting is required
in less time. It is safer then hand saw.
36. FRAMING HAMMER:

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Framing hammer is used to used to drive and remove nails.
37. VIBRATOR:
A concrete vibrator is a construction tool typically used on construction pouring sites. The
vibrators are used to ensure that the pour is free of air bubbles and are even. This is so that the
concrete remains strong and has a smooth finish even after removal of the form work.
TECHNICAL TERMS USED IN MASONRY WORKS
The common terms used in masonry works are listed below.
1. HEADER:
It is a full brick or stone which is laid with its length perpendicular to the face of the wall.
2. STRETCHER:
It is a full brick or stone in which is laid its length parallel to the face of the wall.
3. BOND:
It is a term applied to the overlapping of bricks or stones in a wall in alternate courses, to bind
the whole wall together.
4. COURSE:
A horizontal layer of bricks or stones is termed as course.
5. HEADER COURSE:
It is a course of brickwork entirely composed of headers.
6. STRETCHER COURSE:
It is a course of brickwork in which all the bricks are laid as stretchers.
7. BED:
It is a term used to indicate the lower surface of bricks or stones in each course. It may also be
termed as surface of the bricks on which it rests.
8. FACE:
The surface of a wall exposed to weather is termed as face.
9. FACING:
The material used in the face of the wall is known as facing.

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10. BACK:
The inner surface of the wall which is not exposed to the weather is termed as back.
11. BACKING:
The material used in forming the back of the wall is known as backing.
12. HEARTING:
The portion of a wall between facing and backing is termed as hearting.
13. JOINT:
The junction of two or more bricks or stones is called joint.
14. RACKING BACK:
The process of stopping the unfinished end of a wall in stepped fashion.
15. BAT:
It is a portion of a brick cut across the width or a brick cut by some fraction of its length.
16. CLOSER:
It is a portion of a brick cut in such a manner that its one long face remains uncut.
17. KING CLOSER:
It is a brick which is cut in such a way that the width of one of its end is half that of a full brick.
18. QUEEN CLOSER:
It is a term applied to a brick which is half as wide as full brick. Queen closer is made by cutting
a brick lengthwise into two portions.
19. BEVELLED CLOSER:
It is similar to king closer with the only difference that the whole length of the brick is bevelled
for maintaining half width at one end and full width at the other.
20. MITRED CLOSER:
It is a brick whose one end is cut splayed or mitred for the full width.
21. PERPEND:
It is a vertical joint on the face of a wall directly over vertical joints in an alternate course.
22. FROG:
It is a depression on the top face of a brick. Frog provides a recess for the mortar which on
setting forms a key and prevents the displacement of the brick above.
23. PLINTH:
The horizontal projecting or flush course of stone or brick provided at the base of the wall
above ground level is known as plinth.
24. SILL:
It is a horizontal member of brick, stone, concrete or wood provided to give support for the
vertical members of a window.
25. JAMBS:
The vertical sides of a finished opening for door, window or fire place etc. are termed as jambs.
26. REVEALS:
Reveals are the exposed vertical surfaces left on the sides of an opening after the door or
window frame has been fitted in position.

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27. LINTEL:
A horizontal member of stone, brick, steel or RCC, used to support the masonry or load above
an opening.
28. ARCH:
A mechanical arrangement of wedge-shaped blocks of stone or brick arranged in the form of a
curve supporting the masonry or load above an opening.
29. CORNICE:
It is a horizontal moulded projection provided near the top of a building or at the junction of a
wall and ceiling.
30. PARAPET:
It is a term applied to a low wall built around a flat roof to act as a protective solid balustrade
for the users of the terrace.
31. WEATHERING:
Weathering is the term applied to the bevelled top surface of a stone.
32. GABLE:
It is a triangular shaped portion of masonry at the end of a sloped roof.
33. SPALLS:
Chips or small pieces of stone broken off a large block are termed as spalls.
34. COLUMNS:
It is an isolated vertical load bearing member whose width does not exceed four times its
thickness.
35. PIER:
It is a vertical member of stone or brick masonry constructed to support an arch, beam or lintel
etc.
36. BUTTRESS:
It is similar to pier built on the exterior of a wall properly bonded to it.
37. CORBEL:
It is the extension of one or more course of brick or stone from the face of a wall.
38. THRESHOLDS:
The arrangement of steps provided from ground level to reach plinth level on external doors
and verandah is termed as thresholds.
Stone Masonry
Technical terms used in Stone Masonry.
The following terms are generally used in stone masonry:
1. Natural bed of a stone. The original surface occupied by a stone during its formation,
is called natural bed. Stones are placed in a structure so that super-imposed load acts
perpendicular to the natural bed of stones.
2. Bedding plane. The plane along which a stone can be separated, easily, is called

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bedding plane. Stones are laid in a structure so that load acts perpendicular to them
bedding plane.
3. String course. The course of stone masonry provided at floor level and roof level
projecting horizontally outside the wall of a building, is called string course.
4. Cornice. The course of a masonry provided at ceiling level of the roof projecting outside
the surface of the wall of a building, is called cornice. It is provided to throw rain water
away from the wall and also to add architectural appearance.
5. Throating. A small groove cut on the underside of a projecting chuajja, cornice, coping,
to discharge rain water without trickling to walls, is called throating.
6, Reveals. The exposed vertical surfaces perpendicular to window or door frame, are
called reveals.
7. Drip stone. A projecting dressed stone having its undersurface throated, is called drip
stone.
Tools Used in Stone Masonry Works
The tools used in stone masonry are mostly same as brick masonry but in addition some more
tools are used which are as under: -
Chisel: It is used for cutting stones.
Mallet: It is wooden headed hammer used for wooden headed chisels.
Iron hammer: It is used for carving stones.
Pick: This is used for rough dressing of granite.
Spalling hammer: This is used for rough dressing of stones in quarry.
Claw tool: This is an edge with number of teeth 3mm to 9mm in width. It is used for dressing
the surface of stones.
Pitching tool: It is used for reducing in size of stones.
Jumpers: These are used for making holes in the stones.
Wedge and feathers: These are small conical wedges and curved plates. They are used for
cutting the stones after they have been bored with jumper.
Natural bed of stone: It is the term applied to the original position occupied by the stone
during its formation.
Gads: These are used for splitting the stones.
Saws: These are used for cutting stones with hands.
Supervision of Stone Masonry Construction
The following points should be kept in mind in supervising stone masonry work:
1. Hard and durable stones, free from defects like flaws, cavities veins etc. should be used.
2. Dressing of the stones should be as per the requirement.
3. Stones should be properly wetted before they are used so as to avoid sucking of water from

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mortar.
4. Stones should be laid on their natural bed.
5. Facing and backing faces should be laid neatly and levelled and checked with wooden
template.
6. The heart of masonry should be filled with stone chips and mortars. To thick mortar joints
should be avoided.
7. Verticality of the wall should be frequently checked with plumb-bob.
8. Mortars with correct proportion of sand and cement should be used.
9. Continuous vertical joints should be avoided.
10. Through stones should be used within 1.5 m distances.
11. The height of masonry should be raised uniformly.
12. Under the beams, trusses, sills etc large flat stones should be used.
13. Before continuing work, the masonry built on previous day should be well cleaned and
freed from loose particles.
14. Curing should be done properly for 2 to 3 weeks.
Classification of Stone Masonry
Definition:
The art of building a structure in stone with any suitable masonry is called stone masonry.
Types of Stone Masonry
Stone masonry can broadly be classified into the following two types:
 Rubble Masonry
 Ashlar Masonry
Rubble Masonry:
The stone masonry in which either undressed or roughly dressed stone are laid in a suitable
mortar is called rubble masonry. In this masonry the joints are not of uniform thickness. Rubble
masonry is further sub-divided into the following three types:
Types of Rubble Masonry
 Random rubble masonry
 Squared rubble masonry
 Dry rubble masonry
Random rubble masonry:

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Random Rubble Masonry
Rubble masonry is the type of stone masonry in which either undressed or hammer dressed
stones are used is called random rubble masonry. Further random rubble masonry is also
divided into the following three types:
Un-coursed random rubble masonry:
The random rubble masonry in which stones are laid without forming courses is known as un
coursed random rubble masonry. This is the roughest and cheapest type of masonry and is of
varying appearance. The stones used in this masonry are of different sizes and shapes. before
lying, all projecting corners of stones are slightly knocked off. Vertical joints are not plumbed,
joints are filled and flushed. Large stones are used at corners and at jambs to increase their
strength. Once "through stone" is used for every square meter of the face area for joining faces
and backing.
Suitability: Used for construction of walls of low height in case of ordinary buildings.
Coursed random rubble masonry:
The random rubble masonry in which stones are laid in layers of equal height is called random
rubble masonry. In this masonry, the stones are laid in somewhat level courses. Headers of one
coursed height are placed at certain intervals. The stones are hammer dressed.
Suitability: Used for construction of residential buildings, go downs, boundary walls etc.
Squared rubble masonry:

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The rubble masonry in which the face stones are squared on all joints and beds by hammer
dressing or chisel dressing before their actual laying, is called squared rubble masonry.
There are two types of squared rubble masonry.
Coursed Square rubble masonry:
The square rubble masonry in which chisel dressed stones laid in courses is called coarse square
rubble masonry. This is a superior variety of rubble masonry. It consists of stones, which are
squared on all joints and laid in courses. The stones are to be laid in courses of equal layers. and
the joints should also be uniform.
Suitability: Used for construction of public buildings, hospitals, schools, markets, modern
residential buildings etc and in hilly areas where good quality of stone is easily available.
Un coursed square rubble masonry:
The squared rubble in masonry which hammer dressed stones are laid without making courses
is called un coursed square rubble masonry. It consists of stones which are squared on all joints
and beds by hammer dressing. All the stones to be laid are of different sizes.
Suitability: Used for construction of ordinary buildings in hilly areas where a good variety of
stones are cheaply available.
Dry rubble masonry:
The rubble masonry in which stones are laid without using any mortar is called dry rubble
masonry or sometimes shortly as "dry stones". It is an ordinary masonry and is recommended
for constructing walls of height not more than 6m. In case the height is more, three adjacent
courses are laid in squared rubble masonry mortar at 3m intervals.
Ashlar Masonry:
It is the type of stone masonry in which finely dressed stones are laid in cement or lime mortar
is known as ashlars masonry. In this masonry are the courses are of uniform height, all the
joints are regular, thin and have uniform thickness. This type of masonry is much costly as it
requires dressing of stones.
Suitability: This masonry is used for heavy structures, architectural buildings, high piers and
abutments of bridges.
Ashlars masonry is further sub divided into the following types:
Types of Ashlar Masonry
 Ashlars fine or coarse ashlar masonry
 Random coarse ashlars masonry
 Rough tooled ashlar masonry
 Rock or quarry faced ashlars masonry
 Chamfered ashlars masonry
 Block in coarse masonry
 Ashlar facing
Ashlar fine or coursed ashlar masonry:

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In this type of stone masonry stone blocks of same height in each course are used. Every stone
is fine tooled on all sides. Thickness of mortar is uniform through out. It is an expensive type of
stone masonry as it requires heavy labor and wastage of material while dressing. Satisfactory
bond can be obtained in this type of stone masonry.
Random coursed ashlar masonry:
This type of ashlar masonry consists of fine or coursed ashlar but the courses are of varying
thicknesses, depending upon the character of the building.
Rough tooled ashlar masonry:
This type of ashlar masonry the sides of the stones are rough tooled and dressed with chisels.
Thickness of joints is uniform, which does not exceed 6mm.
Rock or quarry faced ashlar masonry:
This type of ashlar masonry is similar to rough tooled type except that there is chisel-drafted
margin left rough on the face which is known as quarry faced.
Chamfered ashlar masonry:
It is similar to quarry faced except that the edges are beveled or chamfered to 450 for depth of
2.5 cm or more.
Block-in course masonry:
It is the name given to a class of ashlar masonry which occupies an intermediate place between
rubble and ashlars. The stones are all squared and properly dressed. It resembles to coursed
rubble masonry or rough tooled ashlar masonry.
Ashlar facing:
Ashlar facing is the best type of ashlars masonry. Since this is type of masonry is very expensive,
it is not commonly used throughout the whole thickness of the wall, except in works of great
importance and strength. For economy the facing is built in ashlars and the rest in rubble.
OR
1. Rubble Masonry: In this type of constructions stones of irregular sizes and shapes are used.
To remove sharp shapes they may be hammered. The rubble masonry may be coursed or
uncoursed [Fig. 8.1 and 8.2]. In uncoursed rubble masonry the wall is brought to level at
every 300 mm to 500 mm. The mortar consumed in these construction is more. Course
rubble masonry is used for the construction of public and residential buildings. Uncoursed
rubble masonry is used for the construction of foundations, compound walls, garages, labour
quarters etc. A skilled mason may arrange the facing stones in polygonal shapes to improve
the aesthetic of the wall.

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2. Ashlar Masonry: In this type of masonry stones are dressed to get suitable shapes and sizes.
The height of the stones varies from 250 mm to 300 mm. The length should not exceed three
times the height. The dressing of the stone need not be very accurate on all sides. Usually
good dressing is made on facing side. In such construction mortar consumption is less
compared to rubble masonry.
Supervision of Stone Masonry Construction
The following points should be kept in mind in supervising stone masonry work:
1. Hard and durable stones, free from defects like flaws, cavities veins etc. should be used.
2. Dressing of the stones should be as per the requirement.
3. Stones should be properly wetted before they are used so as to avoid sucking of water from

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mortar.
4. Stones should be laid on their natural bed.
5. Facing and backing faces should be laid neatly and levelled and checked with wooden
template.
6. The heart of masonry should be filled with stone chips and mortars. To thick mortar joints
should be avoided.
7. Verticality of the wall should be frequently checked with plumb-bob.
8. Mortars with correct proportion of sand and cement should be used.
9. Continuous vertical joints should be avoided.
10. Through stones should be used within 1.5 m distances.
11. The height of masonry should be raised uniformly.
12. Under the beams, trusses, sills etc large flat stones should be used.
13. Before continuing work, the masonry built on previous day should be well cleaned and
freed from loose particles.
14. Curing should be done properly for 2 to 3 weeks.
Chapter No 13
Sub structure Construction Methodologies
The following are the basic elements of a building:
1. Foundation
2. Plinth
3. Walls and columns
4. Sills, lintels and chejjas
5. Doors and windows
6. Floors
7. Roofs
8. Steps, stairs and lifts
9. Finishing work
10. Building services.
The functions of these elements and the main requirement of them is presented in this article.
1. Foundation: Foundation is the most important part of the building. Building activity starts
with digging the ground for foundation and then building it. It is the lower most part of the
building. It
transfers the load of the building to the ground. Its main functions and requirements are:
(a) Distribute the load from the structure to soil evenly and safely.
(b) To anchor the building to the ground so that under lateral loads building will not move
(c) It prevents the building from overturning due to lateral forces.
(d) It gives level surface for the construction of super structure.
2. Plinth: The portion of the wall between the ground level and the ground floor level is called

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plinth. It is usually of stone masonry. If the foundation is on piles, a plinth beam is cast to
support wall above floor level. At the top of plinth, a damp proof course is provided. It is usually
75 mm thick plain concrete course.
The function of the plinth is to keep the ground floor above ground level, free of dampness. Its
height is not less than 450 mm. It is required that plinth level is at least 150 mm above the road
level, so that connections to underground drainage system can be made.
3. Walls and Columns: The function of walls and columns is to transfer the load of the structure
vertically downwards to transfer it to foundation. Apart from this wall performs the following
functions also:
(a) It encloses building area into different compartments and provides privacy.
(b) It provides safety from burglary and insects.
(c) It keeps the building warm in winter and cool in summer.
4. Sills, Lintels and Chejjas: A window frame should not be directly placed over masonry. It is
placed over 50 mm to 75 mm thick plain concrete course provided over the masonry. This
course is called as sill.
Lintels are the R.C.C. or stone beams provided over the door and window openings to transfer
the load transversely so as to see that door or window frame is not stressed unduly. The width
of lintels is equal to the width of wall while thickness to be provided depends upon the opening
size.
Chejja is the projection given outside the wall to protect doors and windows from the rain.
They are usually made with R.C.C. In low cost houses stone slabs are provided as chejjas. The
projection of chejja varies from 600 mm to 800 mm. Sometimes drops are also provided to
chejjas to improve acsethetic look and also to get additional protection from sun and rain.
5. Doors and Windows: The function of a door is to give access to different rooms in the
building and to deny the access whenever necessary. Number of doors should be minimum
possible. The size of the door should be of such dimension as will facilitate the movement of
the largest object likely to use the door.
Windows are provided to get light and ventilation in the building. They are located at a height
of 0.75 m to 0.9 m from the floor level. In hot and humid regions, the window area should be 15
to 20 per cent of the floor area. Another thumb rule used to determine the size and the number
of windows is for every 30 m3 of inside volume there should be 1 m2 window opening.
6. Floors: Floors are the important component of a building. They give working/useful area for
the occupants. The ground floor is prepared by filling brick bats, waste stones, gravel and well
compacted with not less than 100 mm sand layer on its top. A lean concrete of 1: 4: 8, 100 mm
thick is laid. On this a damp proof course may be provided. Then floor finishing is done as per
the requirement of the owner. Cheapest floor finish for a moderate house is with 20 to 25 mm
rich mortar course finished with red oxide. The costliest floor finish is mossaic or marble
finishing. Other floors are usually of R.C.C. finished as per the requirements of the owner.
7. Roof: Roof is the top most portion of the building which provide top cover to the building. It
should be leak proof. Sloping roof like tiled and A.C. sheet give leak proof cover easily. But they

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do not give provision for the construction of additional floor. Tiled roof give good thermal
protection. Flat roofs give provision for additional floors. Terrace adds to the comfort of
occupants. Water tanks can be easily placed over the flat roofs.
8. Step, Stairs and Lifts: Steps give convenient access from ground level to ground floor level.
They are required at doors in the outer wall. 250 to 300 mm wide and 150 mm rise is ideal size
for steps. In no case the size of two consecutive steps be different. Number of steps required
depends upon the difference in the levels of the ground and the floor. Stairs give access from
floor to floor. They should consists of steps of uniform sizes.
In all public buildings lifts are to be provided for the conveniences of old and disabled persons.
In hostels G + 3 floors can be built without lifts, but in residential flats maximum floors
permitted without lifts is only G + 2. Lift is to be located near the entrance. Size of the lift is
decided by the number of users in peak hours. Lifts are available with capacity 4 to 20 persons.
9. Finishing: Bottom portion of slab (ceiling), walls and top of floor need smooth finishing
with plaster. Then they are provided with white wash, distemper or paints or tiles. The function
of finishing work is:
(a) Give protective cover
(b) Improve aesthetic view
(c) Rectify defective workmanship
(d) Finishing work for plinth consists in pointing while for floor it consists in polishing.
10. Building Services: Water supply, sanitation and drainage works, electric supply work and
construction of cupboards and show cases constitute major building services.
For storing water from municipal supply or from tanker a sump is built in the house property
near street. From the sump water is pumped to over head tanks placed on or above roof level
so as to get water all the 24 hours. Plumbing work is made so as to get water in kitchen,
bathrooms, water closets, sinks and garden taps.
For draining rain water from roofs, down take pipes of at least 100 mm diameters should be
used. Proper slopes should be given to roof towards down take pipe. These pipes should be
fixed at 10 to 15 mm below the roof surface so that rain water is directed to the down take pipe
easily.
The sanitary fittings are to be connected to stone ware pipes with suitable traps and chambers.
Stone ware pipes are then connected to underground drainage of municipal lines or to the
septic tank.
Many carpentry works are required for building service. They are in the form of showcases,
cupboards, racks etc.
Electric supply is essential part of building services. The building should be provided with
sufficient points for supply of lights, fans and other electric gadgets.
BASIC REQUIREMENTS OF A BUILDING
The planning and construction of a building should be aimed at fulfilling the following
requirements:
1. Strength and stability

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2. Dimensional stability
3. Resistance to dampness
4. Resistance to fire
5. Heat insulation
6. Sound insulation
7. Protection against termite attack
8. Durability
9. Security against burglary
10. Lighting and ventilation
11. Comforts and convenience
12. Economy.
1. Strength and Stability: Building should be capable of transferring the expected loads in its
life period safely to the ground. Design of various structural components like slabs, beams,
walls, columns and footing should ensure safety. None of the structural components should
buckle, overturn and collapse.
2. Dimensional Stability: Excessive deformation of structural components give a sense of
instability and result into crack in walls, flooring etc. All structural components, should be so
designed that deflections do not exceed the permissible values specified in the codes.
3. Resistance to Dampness: Dampness in a building is a great nuisance and it may reduce the
life of the building. Great care should be taken in planning and in the construction of the
building to avoid dampness.
4. Resistance to Fire: Regarding achieving resistance to fire, the basic requirements laid down
in the codes are:
(a) the structure should not ignite easily.
(b) building orientation should be such that spread of fire is slow.
(c) In case of fire, there should be means of easy access to vacate building quickly.
5. Heat Insulation: A building should be so oriented and designed that it insulates interior
from heat.
6. Sound Insulation: Buildings should be planned against outdoor and indoor noises.
7. Protection from Termite: Buildings should be protected from termites.
8. Durability: Each and every component of the building should be durable.
9. Security against Burglary: This is the basic need the owner of the building expects.
10. Lighting and Ventilation: For healthy and happy living natural light and ventilations are
required. Diffused light and good cross ventilation should be available inside the building.
11. Comforts and Conveniences: Various units in the building should be properly grouped and
integrated keeping in mind the comfort and convenience of the user.
12. Economy: Economy without sacrificing comfort, convenience and durability is another basic
requirement of the building.

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Chapter No 14
BullDozers:
Bulldozers, a power-operated machine fitted with a blade, adjustable in height and angle, for
pushing, sidecasting, and spreading loose excavated material as for opencast pits, clearing land,
or leveling runways. Also known as angling dozer. It is the strongest or power full machine used
in civil engineering. OR
A bulldozer is a crawler (continuous tracked tractor) equipped with a substantial metal plate
(known as a blade) used to push large quantities of soil, sand, rubble, or other such material
during construction or conversion work and typically equipped at the rear with a claw-like
device (known as a ripper) to loosen densely-compacted materials.
 They are used for moving earth up to a distance of about 100 m and act as a towing tractor
and pusher to scraper machines. They can be track-mounted or wheel-mounted.
 The heavy blade attached to the tractor pushes the material from one place to another.
 The tractor can be of the crawler or the wheeled type.
 Classification of bull dozer
1. Position of blades
 Bull dozers in which the blade perpendicular to the direction of movement
 Angle dozers in which the blade is set at an angle with the direction of movement.
2. Based on mountings
 Wheel mounted,  Crawler mounted.
3. Based on the control
 Cable controlled,  Hydraulically controlled.

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Applications
1. For spreading the earth fill
2. For opening up pilot roads through mountainous and rocky terrains.
3. Clearing construction sites.
4. Maintaining haul roads
5. Clearing land from the trees and stumps
6. back-filling trenches at construction sites by dragging the earth from one place to another.
Introduction to other equipments
It is a common fact that we find a wide variety of construction machines on every
construction sites, which make the construction jobs easy, safe and quicker. Good project
management in construction must vigorously pursue the efficient utilization of labor, material
and equipment.
The use of new equipment and innovative methods has made possible wholesale changes in
construction technologies in recent decades. The selection of the appropriate type and size of
construction equipment often affects the required amount of time and effort and thus the
jobsite productivity of a project.
These act as a backbone in the case of huge construction projects. Proper use of the
appropriate equipment contributes to economy, quality, safety, speed and timely completion
of a project. Equipments are use for highway projects, irrigation, buildings, power projects
etc. Almost 15-30% of total project cost has been accounted towards equipment and
machinery.

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It is therefore important for site managers and construction planners to be familiar with the
characteristics of the major types of equipment most commonly used in construction.
Advantages of utilizing the construction equipments:
 Increase the rate of output through work progress with the best effective and efficient
methods.
 Reduce the overall construction costs especially for large contracts.
 Carry out activities which cannot be done manually or to do them more economically
and much faster.
 Eliminate the heavy manual work by human thus reducing fatigue and eliminates
various other hazards and health issues.
 Maintain the planned rate of production where there is a shortage of skilled or unskilled
labor.
 Maintain the high quality standards often required by present-day design and
specifications (technical standards).
CLASSIFICATION OF CONSTRUCTION EQUIPMENTS
Depending on the application, construction machines are classified into various categories
which we are discussing here.
1. Earth-moving equipment
2. Earth-compacting equipment
3. Hauling equipment
4. Hoisting equipment
5. Conveying equipment
6. Aggregate production equipment
7. Equipments used in Concrete Construction.
8. Pile-driving equipment
1. Earth-moving equipment
1. Excavators
 Excavators are heavy construction equipment consisting of a boom, stick, bucket and cab on a
rotating platform (known as the "house").
 The house sits atop an undercarriage with tracks or wheels.
 Excavators are also called diggers
 Excavators are used in many ways:
a. Digging of trenches, holes, foundations
b. Material handling
c. Brush cutting with hydraulic attachments
d. Forestry work
e. Demolition
f. General grading/landscaping
g. Heavy lift, e.g. lifting and placing of pipes

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h. Mining, especially, but not only open-pit mining
i. River dredging
j. Driving piles, in conjunction with a pile driver
2. Back hoe
 Backhoes are mainly used to clean up construction areas, to dig holes in the ground, to
smooth uneven ground, to make trenches, ditches and to help remove deep roots from
trees.
 It can exert high tooth pressures and hence can excavate stiff material which normally
cannot be excavated by dragline. Out put of hoe is greatest when the excavation is done
near the machine, because cycle time of operation reduces.
 A backhoe, also called a rear actor or back actor, is a piece of excavating equipment or
digger consisting of a digging bucket on the end of a two-part articulated arm. They are
typically mounted on the back of a tractor or front loader.
 Also known as hoe, back shovel and pull shovel
 It is used to excavate below the natural surface on which it rests.
 Generally used to excavate trenches, pits for basements and also for grading works,
which requires precise control of depths.
 The basic parts are boom, Jack boom, Boom foot drum, Boom sheave, Stick
sheave, Stick, Bucket and Bucket sheave.

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The section of the arm closest to the vehicle is known as the boom, and the section
which carries the bucket is known as the dipper or dipper stick (the terms "boom"
and "dipper" having been used previously on steam shovels). The boom is attached
to the vehicle through a pivot known as the kingpost, which allows the arm to slew
left and right, usually through a total of around 200 degrees. Modern backhoes are
powered by hydraulics.
Applications:
• It is the most suitable machine for digging below the machine level, such as,
trenches, footings, basements etc.
• It can be efficiently used to dress or trim the surface avoiding the use of manual
effort for dressing the excavated the surface.
3. Front shovel
 A front shovel (also stripping shovel or power shovel or electric mining shovel or Dipper
Shovel's power shovel) is a bucket-equipped machine, usually electrically powered, used for
digging and loading earth or fragmented rock and for mineral extraction.
 They are mounted on crawler tracks.
 To excavate the earth and to load the trucks
 It is used to excavate earth of all classes except hard rock and load it into wagons.
 Size varies from 0.375m3 to 5m3.
 Basics parts of power shovel including the track system, cabin, cables, rack, stick,
boom foot-pin, saddle block, boom, boom point sheaves and bucket.
 Power shovels are used principally for excavation and removal of overburden in opencut
mining operations, though it may include loading of minerals, such as coal. They
are the modern equivalent of steam shovels, and operate in a similar fashion.
 Front shovel are mainly used for excavation purposes above its own track or wheel level.
 They are suitable for heavy positive cutting in all types of dry soils.

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4. Dragline
 They are used to excavate soft earth from below ground and to deposit or to load in
wagons. Output of dragline is measured in Cubic Meters per hour.

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 They are used for bulk excavation below its track level in loose soils, marshy land and
areas containing water.
 The drag line is so name because of its prominent operation of dragging the bucket
against the material to be dug.
 Unlike the shovel, it has a long light crane boom and the bucket is loosely attached to
the boom through cables.
 Because of this construction, a dragline can dig and dump over larger distances than a
shovel can do.
 Drag lines are useful for digging below its track level and handling softer materials.
 The basic parts of a drag line including the boom, hoist cable, drag cable, hoist chain,
drag chain and bucket.

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Applications of Dragline:
 It is the most suitable machine for dragging softer material and below its track level
 It is very useful for excavating trenches when the sides are permitted to establish their
angle of repose without shoring.
 It has long reaches.
 It is mostly used in the excavation for canals and depositing on the embankment
without hauling units.
5. Clamshell
 It consists of a hydraulically controlled bucket suspended from a lifting arm. It is
mainly used for deep confined cutting in pits and trenches.
 It is having bucket of two halves which are hinged together at top. It is used to excavate
soft to medium materials and loose materials.
 This is so named due to resemblance of its bucket to a clam which is like a shell-fish
with hinged double shell.
 The front end is essentially a crane boom with a specially designed bucket loosely
attached at the end through cables as in a drag line.
 The capacity of a clam shell bucket is usually given in cubic meters.
 The basic parts of clam shell bucket are the closing line, hoist line, sheaves, brackets,
tagline, shell and hinge.

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Applications of Clamshell:
• Used for handling loose material such as crushed stone, sand, gravel, coal etc.
• Main feature is vertical lifting of material from one location to another.
• Mainly used for removing material from coffer dam, sewer main holes, well foundations etc.
6. Bulldozers
 A bulldozer is a crawler (continuous tracked tractor) equipped with a substantial metal plate
(known as a blade) used to push large quantities of soil, sand, rubble, or other such material
during construction or conversion work and typically equipped at the rear with a claw-like
device (known as a ripper) to loosen densely-compacted materials.
 They are used for moving earth up to a distance of about 100m and act as a towing tractor
and pusher to scraper machines. They can be track-mounted or wheel-mounted.
 The heavy blade attached to the tractor pushes the material from one place to another.
 The tractor can be of the crawler or the wheeled type.

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7. Scraper
 It is a device to scrap the ground & load it simultaneously, transport it over required
distance. It can dig, load, haul and discharge the material in uniformly thick layers.
 In civil engineering, a wheel tractor-scraper is a piece of heavy equipment used for
earthmoving.
 The rear part has a vertically moveable hopper (also known as the bowl) with a sharp
horizontal front edge. The hopper can be hydraulically lowered and raised. When the
hopper is lowered, the front edge cuts into the soil or clay like a plane and fills the
hopper.
 When the hopper is full it is raised, and closed with a vertical blade (known as the
apron). The scraper can transport its load to the fill area where the blade is raised, the
back panel of the hopper, or the ejector, is hydraulically pushed forward and the load
tumbles out. Then the empty scraper returns to the cut site and repeats the cycle.
 They are used for site levelling, loading, hauling over distances varying between
150m-900m. They may be towed, two-axle or three-axle type.
 Unique machine for digging and long-distance hauling of plough able materials.
 self-operating machine

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 It is not dependent on other equipment.
 Wheels of machine cause some compaction.
 The basic parts of scrapers are the bowl, apron and tail gate or ejector.
8. Grader
 A grader, also commonly referred to as a road grader, a blade, a maintainer, or a
motor grader, is a construction machine with a long blade used to create a flat surface.
 Typical models have three axles, with the engine and cab situated above the rear axles
at one end of the vehicle and a third axle at the front end of the vehicle, with the blade
in between.
 In civil engineering, the grader's purpose is to "finish grade" (refine, set precisely) the
"rough grading" performed by heavy equipment or engineering vehicles such as
scrapers and bulldozers.
 Graders are commonly used in the construction and maintenance of dirt roads and gravel
roads.
 In the construction of paved roads they are used to prepare the base course to create a
wide flat surface for the asphalt to be placed on. Graders are also used to set native
soil foundation pads to finish grade prior to the construction of large buildings.
 It is used for grading and finishing the upper surface of the earthern formations and
embankments. They usually operate in the forward direction
 It is self propelled or towed machine motor grader, Used for light or medium works. It
shapes the ground and spreads the loose material..

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9. Loaders
 A loader is a heavy equipment machine often used in construction, primarily used to
lift material (such as asphalt, demolition debris, dirt, snow, feed, gravel, logs, raw
minerals, recycled material, rock, sand, and woodchips) into or onto another type of
machinery (such as a dump truck, conveyor belt, feed-hopper, or railcar).
 A bucket is attached to arms , capable of being raised, lowered and dumped through
mechanical control. Application-Land filling, road Maintenance.
 Skid-Steer Loader:
 A skid loader or skid-steer loader is a small rigid frame, engine-powered
machine with lift arms used to attach a wide variety of labor-saving tools or
attachments.
 Though sometimes they are equipped with tracks, skid-steer loaders are typically
four-wheel vehicles with the wheels mechanically locked in synchronization on
each side, and the left-side drive wheels can be driven independently of the rightside drive
wheels.

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 Wheeled Loader
 Crawler Loader

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 The crawler loader combines the stability of the crawler tractor with the abilities of
a wheel loader.
 However, to construct a reliable crawler loader it requires more than simply
attaching a loader bucket onto a crawler tractor. It must be designed with its specific
purpose in mind to ensure it has the strength to withstand heavy excavating.
 The introduction of hydraulic excavators diminished the market for the crawler
loader because it was unable to match the excavator's lifting power and flexibility.
 However, crawler loaders are capable of maneuvering across the entire construction site
under its own power, whereas most hydraulic excavators require towing or transport. While
crawler tractors are still being manufactured today for niche markets, they reached their peak
of popularity in the 1960s.
10.Trenching Machines
 Trenchers, or ditchers as they are sometimes called, are similar to excavators in the sense
that they penetrate the earth, breaking soil and rock, and remove it from the ground. They
differ from excavators in that the soil is removed in one continuous movement. Trenchers are
specifically used for digging trenches for pipes, but other machines have been improvised in the
past to serve this purpose.
 Trenchers can come in two types: ladder trenchers and wheel trenchers, and can dig
trenches at speeds that other machines cannot compare to.
 Used for excavating trenches for laying pipelines, sewer, cables etc.
 Operation is quick giving the required depth or width.
 Two types of trenching machine are wheel type and ladder type

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11. Tractors
 Multi-purpose machines used mainly for pulling and pushing the other equipment.
 Important Equipment for earthmoving, worked by Diesel engines, having horse power
ranging from 20HP to 200HP.
 Tractors may be classified as
a) Crawler type tractor- Used to move bull dozers, scrapers. The crawler has a chain by
which these tractors can be very effective even in the case of loose or muddy soils.
The speed of this type dose not exceed 12 kmph normally.

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b) Wheel type tractor- The engine is mounted on four wheels. The main advantage is
higher speed, sometimes exceeding 50 kmph it is used for long-distance hauling and
good roads.
EARTH COMPACTING EQUIPMENTS
Following are the equipments used for the compaction of earth:
1. Smooth Wheel Roller
2. Sheep Foot Roller
3. Pneumatic Roller
4. Tamping Roller
5. Grid Roller
6. Vibratory Roller
1. SMOOTH WHEEL ROLLER:

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This types of roller incorporates a large steel drum at the front and one or two wheels or drums
at the rear. If their is one wheel at the rear they are known as Tandem roller, and Three
wheeled roller if there are two wheels at the rear.
The weight of tandem roller varies from 2-8 tonnes and three wheeled roller varies from 8-10
tonnes. The ground pressure exerted by tandem roller is typically around 10-17 kg/cm2.
The weight of roller increased by blasting with sand, water or pig iron.
Smooth wheel roller is most suitable for consolidating stone, gravel, sand, hardcore and ballast
but are not suitable for embankments, soft sub-grades or uniform sand.
The Speed and number of passes of a smooth wheel roller depends on the types of soil to be
compacted and project requirements.
The optimum working speed has found to be 3-6 km/h and about 8 passes are adequate for
compacting 20 cm layer.
The smooth wheel roller leaves the surface smooth after compaction.
2. SHEEP FOOT ROLLER:
Sheep foot roller consist of a steel drum on which round or rectangular protrusions known as
lugs or feet are fixed.

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There are different types of lugs such as spindle shaped with widened base, prismatic and
clubfoot.
Sheep foot roller are used for compacting fine grained soil such as heavy clay and silty clay.
They are used for compaction of soils in dam, embankments, sub-grade layers in pavements
and rail road construction projects.
Coverage area of sheep foot roller is less about 8-12 % because of the boots on drums.
Contact pressure of this type roller varies from 1200-7000 Kpa.
Area of each protrusion in sheep foot roller varies from 30-80 cm2.
Generally, 10-20 passes are required to provide complete coverage on the soil and top layer of
consolidated soil finished by smooth wheel roller.
Factors that governs the amount of compaction of soil are-
1- Weight of roller
2- Area of each lugs
3- No. of lugs in contact with the ground
4- No. of lugs per drum
3. PNEUMATIC ROLLER:
Pneumatic roller consists of a heavily loaded wagon with with several rows of closely spaced
tyres. They are also known as rubber tyred roller.
They provide uniform contact pressure through out the width covered and are often used in
pavement sub-grade works.
They are suitable for compacting uniform coarse soil and rock. They are also used to finish
embankment compacted by sheep foot roller.
The factors which affect the amount of compaction that can be achieved are the weight, tyre
inflation pressure and the area of contact.
Coverage area of pneumatic roller is about 80%.
Contact pressure of pneumatic roller ranges from 500-700 Kpa.
The optimum speed of roller is between 6-24 km/h and maximum density can be achieved by 8
passes of the roller.

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The gross weight of roller 6-10 tonnes which can be increased to 25 tonnes by ballasting.
4. TAMPING ROLLER:
The tamping rollers are similar to sheep foot roller.
Tamping roller consist of four wheels and one each wheel kneading boots/feet are fixed.
These rollers also consist of leveling blades to spread the material.
Tamping roller has more coverage area about 40-50%.
Contact pressure of tamping roller varies from 1400-8500 Kpa.
Tamping roller is best dedicated for fine grained soils.
Tamping roller have static weight in the range of 15-40 tonnes and their static linear drum loads
are between 30-80 kg/cm.
The degree of compaction achieved is more than sheep foot roller and density achieved by
tamping roller after compaction is more uniform.
5. VIBRATORY ROLLER:
Vibratory roller has fitted with one or two smooth surfaced steel drums measuring 0.9-1.5 in
diameter and 1.2-1.8 in width.
The drum vibrates by the rotation of an electric shaft inside.

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Vibratory roller is commonly used for compacting granular base course and some times for
asphalt. Tamping roller have higher output and improved performance compared to other
rollers.
6. GRID ROLLER:
Grid roller have a cylindrical heavy steel surface comprising a network of steel bars which form
a grid with square shaped holes.
They are typically used for the compaction of well graded coarse soil and weathered rocks,
often in sub-grades and sub-base road projects.
They are not suitable for clayey soil, silty clay or uniform soil.
The weight of grid roller con be increased by ballasting with concrete blocks.
Typical weight of grid roller varies between 5.5 tonnes net and 15 tonnes ballasted.
This roller provides higher contact pressure but little kneading action.
3. HAULING EQUIPMENTS
 The equipment used for transportation of material are known as hauling equipment or
simply haulers.
 Haulers may operate on the roadways or railways
 It involve
• transportation of building materials,
• carriage and disposal of excavated earth
• Haulage of heavy construction equipment.
 Haulage by road is carried out by trucks, rubber tyred tractor with wagons or crawler
tractor with wagons. It transports the earth, aggregate, rock, ore, coal and other
materials. Road vehicles used for haulage on construction work are two types.
1. On Highway Vehicle-Design to be used on Public Highways
2. Off Highway Vehicle-Designed to be used construction sites & designed and
manufactured to preclude there use on their use on public roads and they may or
may not comply highway limitation.

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1. Truck
 They have high mobility, good speed and adoptability. The truck capacity varies from
0.4 Cum to 20 Cum & speed vary from 10 kmph to 30 kmph.
2. Dump Truck
 These are the trucks which are fitted with automatic unloading devices. The
loading is normally done by loading shovels or loaders. The trucks have capacity
as high as 53 tones. These trucks can be rear dump truck.
 These are used for earth moving purpose.
 The selection of the type of dump trucks for a specific job depend on the soil condition.
(a) Side or rear dump trucks-
• These are heavy duty trucks with strongly built body which is hinged on the truck chassis at
the rear end and one side respectively, and can be fitted to the rear in the case of rear dump
and to the hinged side in case of the side dump, through the action of hydraulic jacks.
• These trucks are suitable for use in hauling wet clay, sand, gravel, quarry rocks etc.

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(b) Bottom dump trucks
• These are similar to semi-trailers in which their front is supported on the rear of
the hauling tractor and their rear is resting on their own wheels.
• The body of the truck remains in the same position and the discharge of the
material takes place through its bottom after opening of two longitudinal gates.
• The gates are hinged to the side of the body.
• These trucks are suitable for use in hauling free flowing material, such as, sand,
gravel, dry earth, hard clay etc.

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3. Dumpers
 A dumper is a vehicle designed for carrying bulk material, often on building sites. Dumpers
are distinguished from dump trucks by configuration: a dumper is usually an open 4-wheeled
vehicle with the load skip in front of the driver, while a dump truck has its cab in front of the
load.
 The skip can tip to dump the load; this is where the name "dumper" comes from. They are
normally diesel powered. A towing eye is fitted for secondary use as a site tractor. Modern
dumpers have payloads of up to 10 tones and usually steer by articulating at the middle of the
chassis.
 High speed pneumatic wheeled trucks
4. Short chassis
5. Strong bodies
6. Loading, hauling and dumping is done very fast as compared to other equipment
7. Suitable for short hauls on rough roads
8. Especially where a shuttle movement is required.

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4. Tippers
 A truck or lorry the rear platform of which can be raised at the front end to enable
the load to be discharged by gravity also called tip truck.
 Tippers are suited for the rough and tumble of mining & quarrying operations, as
well as for carrying bulk loads in construction and infrastructure industries.
Complete maneuverability, high performance and long-term endurance are
common to all trucks, resulting in lower operating costs.

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5. Ttrailers
 A trailer is generally an unpowered vehicle pulled by a powered vehicle.
 Commonly, the term trailer refers to such vehicles used for transport of goods and materials.

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4. HOISTING EQUIPMENTS
• Hoisting is the lifting a weight from one location and moving it to another location
which is at a reasonable distance.
• These equipments are used for lifting the loads, holding them in suspension during
transfer from one place to other and placing them at designated location.
• Big projects such as, construction of dams, industrial buildings etc. require hoisting
equipment.
• Hoisting equipment includes jacks, winches, chain hoists and cranes.
• Crane is the only single machine which, as a single piece, is capable of providing
three-dimensional movement of a weight.
• It constitutes a group of equipment which are employed mainly for lifting or lowering
of unit load and other.
Forklifts
 A forklift truck (also called a lift truck, a fork truck, a forklift, or a tow-motor) is
a powered industrial truck used to lift and transport materials.
 Forklift trucks are available in many variations and load capacities. In a typical

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warehouse setting most forklifts used have load capacities between one to five tons.
Larger machines, up to 50 tons lift capacity are used for lifting heavier loads.

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HOISTS
 A hoist is a device used for lifting or lowering a load by means of a drum or liftwheel around
which rope or chain wraps. It may be manually operated, electrically
or pneumatically driven and may use chain, fiber or wire rope as its lifting medium.
The load is attached to the hoist by means of a lifting hook
 Also known as a Man-Lift, Buck hoist, temporary elevator, builder hoist, passenger
hoist or construction elevator, this type of hoist is commonly used on large scale
construction projects, such as high-rise buildings or major hospitals. There are many
other uses for the construction elevator.
 Many other industries use the buckhoist for full time operations. The purpose is
being to carry personnel, materials, and equipment quickly between the ground and
higher floors, or between floors in the middle of a structure.
a. Boom Hoist
 Boom hoists are used to lift weights on the hooks that are attached to the special
metal ropes designed to bear maximum loads.
 Boom hoist is mostly used as industrial machine where it loads the weight on containers.
b. Chain Hoist
 Chain hoists are quite common example of hoist system and it can be seen at most of the
construction and industrial purposes. Basically, chain hoist consists of chain rope and pulley
that is used to move the load from up to down.

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c. Electric Hoist
 Electric hoist is modernized form of chain and boom hoist mostly used in the
industries for fast working.
 It is very much popular in material handling industries because it saves labor costs
by handling maximum loads at a time with no damage threats.
 Electric hoist is modernized form of chain and boom hoist mostly used in the
industries for fast working.
 It is very much popular in material handling industries because it saves labor costs
by handling maximum loads at a time with no damage threats.

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d. Tractor Hoist
 Tractor hoist consist of a boom that is attached with base of tractor and a hook with
rope is installed on this boom that can operated through driver controls.

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CRANES
 A crane is a type of machine, generally equipped with a hoist, wire ropes or chains,
and sheaves, that can be used both to lift and lower materials and to move them
horizontally. It is mainly used for lifting heavy things and transporting them to other
places.
 It uses one or more simple machines to create mechanical advantage and thus move
loads beyond the normal capability of a man. Cranes are commonly employed in the
transport industry for the loading and unloading of freight, in the construction
industry for the movement of materials and in the manufacturing industry for the
assembling of heavy equipment.
 Cranes are considered to be one of the most important equipment used in construction
due to their key role in performing lifting tasks all over the construction site.
 Plenty of crane models are available in different shapes and sizes.
1. Derrick cranes-
 Derrick cranes consist of a mast, a boom and a bull wheel on which the boom rotates about a
vertical axis and guys or supporting members.
 Preferable for high-rise and apartment buildings.
 Can be used for both long term and short term projects.
 Cheaper than mobile and tower cranes. Not considered to be safe.
 Used when clearance is inadequate for the other units and sufficient space is unavailable for
the erection of a tower foundation.

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 Electrically operated, diesel operated or diesel-electrically operated.
 The boom can revolve through 360º. This crane is used for heavy loads upto 200 tons.
2. Mobile cranes-
 These cranes are mounted on mobile units which is either crawler type or wheel
type
 Truck cranes have high mobility while the crawler mounted cranes move slowly.
 Crawler mounted cranes are capable of moving on rough terrain.
 Adequate for all types of structures (up to 107 m)
 Used for shorter projects duration (less than 4 months).
 Not considered to be very safe due to lack of safety devices or limited switches to
prevent overloading.
 Can operate in muddy terrain but requires good ground conditions.
 Needs adequate operating clearance

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3. Overhead or gantry cranes-
 large service area,
 freedom from floor obstructions
 and three-way mobility,
 Widely used in erection, foundry, steel plants, storage yards and different types of industrial
works.
 These type of cranes consist of two main parts i.e., the bridge and the crab.
 The bridge consists of two main girders fixed at their end to end and capable of moving on
gantry rails.
 The crab consists of the hoisting gear mounted on a frame.
 The frame itself is mounted on another set of wheels and capable of travelling across the
main girder.
4. Traveler cranes
 Travelling or bridge cranes have their crabs moving on girders which are supported
on legs instead of on overhead gantry track as used in overhead cranes.
 The legs are capable of moving on tracks laid on the floor.
5. Tower cranes
 Tower cranes are actually a derrick crane mounted on a steel tower.

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 Tower cranes are usually used for industrial and residential high-rise buildings.
 These are commonly used for assembly of industrial plants with steel structures.
 The main parts of tower crane are under carriage, slewing platform, tower with
operator’s cabin and jibs.
 The tower has a truss structure welded from steel bars and channels.
 Preferable for high-rise (over 107 m).
 Used for longer project duration.
 Considered to be very safe due to the presence of limit switches.
 Can operate where ground conditions are poor.
 Does not need adequate operating clearance.
5. CONVEYING EQUIPMENTS
 A conveyor system is a common piece of mechanical handling equipment that moves
materials from one location to another. Conveyors are especially useful in
applications involving the transportation of heavy or bulky materials. Conveyor
systems allow quick and efficient transportation for a wide variety of materials, which

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make them very popular in the material handling and packaging industries
 Transporting material from one place to another over a stationary structure.
 Caries material in continuous stream with its distinct feature such as endless chain or belt.
 Can be done horizontally, vertically or inclined.
 When the equipment does horizontal conveying, it is known as conveyor and when it
does vertical, it is known as elevator.
 Conveying are mainly used in mining, construction and in some of the industries.
 In construction industry, conveyors are mainly used for concreting purpose.
Utility
The Advantage of using conveyors are as follows:-
 It increases the output.
 It facilitates continuity in operation.
 It results in time saving.
 There are no waiting periods.
1. Belt conveyor
 Used when large quantities of materials have to be conveyed over long distances at fast
speed.
 It consists of a belt running over a pair of end drums or pulleys and supported at
regular intervals by a series of rollers called idlers.
 These idlers are supported on a conveyor frame.
 The middle sag provided in the belt prevents the spilling of material.
 Generally, rubber is most commonly used as conveyor belt.
The advantages of using belt conveyor are as follows:-
1. It can handle light as well as heavy materials, dry or wet, fine or coarse etc.
2. It can and for distances to convey several thousand tons of material per hour and for
distances of distances of several kilometers.
3. It can carry material horizontally or inclined.

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4. It is lighter in weight then other conveyors.
5. It gives controlled discharge of material and discharge can be controlled by the speed
of the belt.
2. Screw conveyor
 Widely used for handling granular or pulverized material.
 The quantity of material conveyed is less compared to the conveyor, but at the same
time the cost is also less.
 A screw conveyor consists of a helix mounted on a bearing at the ends and at
intermediate points and is driven by a motor from one end.
 The material enters the through at one end is carried to the other end by screwing
action of helix.
 The length of the conveyor is about 65m. with an inclination up to a maximum of 350.
3. Bucket conveyor
 It has buckets in the shape of ‘V’ which are open at the top.
 They may be feeder loaded or may drag in a vertical movement or along an incline.
 The length of these type of conveyors are generally limited to 25 m. (due to weight
of the conveyor and strength of the chains.)
 This type of conveyer is mainly used in coal handling where bucket elevators carry
the material vertically.

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4. Aerial transport
 Aerial transportation through cableways, rope-ways and tram ways
 Often used with advantage for transportation of material in hilly regions.
 Reducing the distance of transportation as well as cost of transportation
 The load being passed over intermediate towers or stations for long distances.

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6. Aggregate production equipment
 Aggregate has to be produced at the site, if the quantity needed is very large.
 Therefore, in any project where concrete requirement is very high, an aggregate
preparation and processing plant is essential to complete the concreting operations.
 Aggregate production consists of two stages is recovery and processing.
 Basic material, such as stone, is recovered from a rock quarry or from the river bed and
processing is done which consists of crushing, grading, washing and stock piling of aggregate.
 Crushers are used mainly to reduce the size of large stone or rock to smaller uniform
sized aggregates required for concrete mix.
 Crushing consists of  Pressure,  Impact,  Attrition  A combination of these operations.
1. Jaw crushers
 It is one of the primary crushers.
 It operates by allowing stone to flow into the space between two jaws, one of
which is stationary and other is movable, which together constitute the crushing

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surfaces.
 The distance between the two jaws decreases as the stone travels downward under
the effect of gravity and ultimately passes through the lower opening.
 The moveable jaw is capable of exerting a pressure sufficiently high to crush the hardest
rock.
 The movable jaw is suspended from a shaft mounted on bearings on the crusher frame.
 The jaw plates are made of manganese steel which can be removed, replaced or reversed.
2. Gyratory crusher
 This is another type of primary crusher.
 This type of crusher comprises a hardened steel head has a long conical shape, with
a trough shaft suspended in a bearing at the top, and an eccentric base connection connected
to gears.
 Thus, as the cone is rotated, the gap between itself and the walling changes from a
maximum to minimum for each cycle.
 The rock is feed into the chamber at the top and as it moves downward, crushing is
done and finally emerges through the bottom gap.
 The size of this type of crusher is the width of the receiving opening measured
between the concaves and the crushers head.
 It is available in sizes varying from 20cm to 200cm.

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3. Cone crusher
 Cone crusher are used as a secondary or tertiary crusher.
 These crusher are capable of producing large quantities of uniformly fine crushed stone.
 It has a shorter cone with smaller inlet and outlet openings as compared to the gyratory crusher.
4. Roll crusher
 Roll crushers are also one of the secondary or tertiary crushers.
 This crusher consists of a heavy cast iron frame equipped with two counter rotating

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rollers mounted on a separate horizontal shaft.
 The crushed rock from the primary crusher is feed through the gap between the two
rollers for crushing further.
 Usually one roller has a fixed axis while the other can be adjusted to give the required
setting.
 The crusher is compact, light weight and low in cost.
5. Hammer mill
 Hammer mill is one of the impact crushers mostly used as primary or secondary crusher.
 It consists of a housing frame, a horizontal shaft extending through the frame, number of
frames and hammers attached to the frame and one more hard steel breaker plates.
 As the stone is feed to the mill, the hammers, which are driven by a motor, move at the high
speed and brake the stone into pieces and driving them against the hard plate, further reduce
their size.

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6. Rod mill and ball mill
 These are the tertiary crushers.
 A rod mill consists of a circular steel shell.
 The interior of the shell is lined on the inside with a hard material wearing surface.
 The shell contains a number of steel rods.
 The length of these rod is slightly less then the length of the shell.
 Crushed stone is feed through the inlet and fine aggregate of the size of sand is discharged at
the other end.
 If the rods are replaced by steel balls to provide the impact required the grind the stones, the
crusher are known as the ball mill crusher.
 The size of the balls generally used is 50 mm dia. Size.
7. CONCRETING EQUIPMENTS
 They are mainly used for weighing and mixing large quantity of concrete constituents.
capacity:- 20cum/hr-250cum/hr
 Concrete is basically cement, aggregate & water mixed together and then deposited
and permitted to solidify.
 Operation involved in concrete production batching, mixing, handling and

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transportation, placing, finishing curing.
 In huge concreting concrete and quality depends on time of mixing, so mixers are used.
1. Concrete production plants
 For mixing different ingredients in required proportion.
 It consists of storage bins for storing materials like cement and admixtures.
 Aggregate is mix in it with the help of a hopper which is fixed in plant.
2. Concrete mixers
 A concrete mixer (also commonly called a cement mixer) is a device that homogeneously
combines cement, aggregate such as sand or gravel, and water to form concrete. A typical
concrete mixer uses a revolving drum to mix the components. For smaller volume works
portable concrete mixers are often used so that the concrete can be made at the construction
site, giving the workers ample time to use the concrete before it hardens.
 Special concrete transport trucks (in–transit mixers) are made to transport and mix concrete
up to the construction site. They can be charged with dry materials and water, with the mixing
occurring during transport. With this process, the material has already been mixing. The
concrete mixing transport truck maintains the material's liquid state through agitation, or
turning of the drum, until delivery.

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 They are mainly used for mixing small quantities of concrete constituents.
 Capacity:- 200lt/batch (small mixers) 200-750l/batch (large mixers)
3. Concrete transit mixers
 They are mainly used for transporting concrete from batching point.
 capacity:- 3cum- 9cum

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4. Concrete pumps
 They are used for horizontal and vertical transportation of large volumes of concrete in short
duration.
 capacity:- 30cum/hr (ordinary construction). 120cum/hr (specialized construction)

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5. Vibrator
 For compacting the concrete after its placement concrete vibrator is used. It help
volume of concrete quickly placed, give high density , reduce air voids.
 Types of Vibrators
 Internal vibrators-Use on large work for flat slab.
 External or form vibrators-uses for thin section of walls.
 Surface vibrator-used to finish concrete surface such as bridge floor, road slab, section platform.
 Table Vibrator-used for consolidation of precast units.

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8. Pile driving equipment
 The process of pile driving involves lifting the piles into position, holding it to refusal
or to a specified depth.
 Driving is accomplished through hammering the pile top with a hammer.
 Equipment are so designed for driven effectively at an economical cost.
 Major pile driving equipment are:

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 Pile driving rigs
 Pile driving hammers

Materials & Methods of Construction - CE145

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Materials & Methods of Construction - CE145