2. UNIT 1 INTRODUCTION TO BUILDING MATERIALS
A building material are the materials which are used for constructing structure for the
building.
Building materials may be categorized in two ways
First classification is based on the source of availability of the material namely, natural
and manufactured. In other classification, building materials are divided into two
groups: Traditional and modern building materials.groups: Traditional and modern building materials.
The traditional building materials are generally the naturally occurring substances,
whereas modern building materials, mainly synthetic materials, are made in industrial
settings such as plastic, plywood etc..
3. 1.1 TRADITIONAL BUILDING MATERIALS
The traditional building materials are generally the naturally materials divided into two
categories namely,
1. inorganic building materials which include unfired clay, sand, stone, lime and hemp-
lime concrete;
2. Organic building materials like wood, straw boards, bamboo etc...
1.1.1 Earth (Sand and clay)
â˘Larger amounts of clay usually mean using the cob/adobe type construction.
⢠low clay soil is usually associated with sod building.
⢠Adobe is made from sand, clay, water and some kind of fibrous or organic material
(straw, grass and or nature), which is shaped into bricks.
⢠Clay , cement and sand can be used in manufacture of stabilized earth blocks⢠Clay , cement and sand can be used in manufacture of stabilized earth blocks
Adobe structures are durable, in fact some of these buildings have remained habitable
for hindered years.
The advantages of using this material are
1. Lower environmental impact
2. its ability to regulate moisture
3. aesthetics
4.lower cost material
5. easily available and plentiful in many parts of the world and 6. Homes built
with earth tend to be naturally cool in the summer and warm in cold weather since clay
holds heat or clod, releasing it over a period of time.
6. 1.1.2 STONE
Stone has been defined as the natural, hard substance formed from minerals and earth
material which are present in rocks. Rock may be defined as the portion of the earthâs
crust having no definite shape and structure.
Rock-forming minerals are quartz, feldspar, mica, dolomite, etc. The various types of
rocks from which building stones are usually derived are granite, basalt, trap, marble,
slate, sandstone and limestone.
Stone has been used in the construction of most of the important structures sinceStone has been used in the construction of most of the important structures since
prehistoric age. Most of the forts world over, the Taj Mahal of India, the famous
pyramids of Egypt and the great wall of China etc...............
However, now days building material stone has gradually lost importance with the
advent of cement and steel.
It is dense material, its main drawback as a material is its weight and gracelessness.
8. 1.1.3 Lime- Calcium carbonate
1.1.4 Hemp-lime concrete
1.2 ORGANIC BUILDING MATERIALS
1.2.1 Straw
â˘Straw is one of the oldest building materials, commonly used in thatch roofs.
â˘Thatch roofs is the primitive roofing method which has been used in both tropical and
temperate climates in developing countries extensively due to low cost.
⢠Straw is also used as cladding material within structural frame.⢠Straw is also used as cladding material within structural frame.
⢠Straw boards have good insulative and thermal properties
⢠The straw can be used in prefabricated panels of close compressed boards within a
timber frame. (manufactured in advance and then assembled on site). These panels can
be quickly installed and create a sustainable product.
â˘These type of straw structures are generally found in tropical (the warm, hot areas
located between the Tropic of Cancer and the Tropic of Capricorn.) and sub-tropical
areas like rainforests, where very large leaves can be used in the building. These are
built mostly with branches, twigs and leaves.
â˘
11. 1.2.2 BAMBOO
a tall tropical grass with hard, hollow stems, or the stems of this plant is known as
bamboo.
Bamboo can be used for flooring, roofing, houses and bridges
Bamboo House
13. 1.5.3 WOOD
The substance making up the central part of the trunk and branches of tree is known as
wood.
Wood products of trees are commonly used for construction purposes when cut or
presses and laminated into lumber and timber like boards or planks (plywood's).
Limitations of using the organic materials.
⢠Organic construction materials are suspected to insert attacks. It requires a regular
inspections.
⢠Need skilled workers to ensure proper construction.
⢠seepage of water will be more
14. 2. BUILDING STONES
Natural stone is perhaps the oldest, most abundant and most durable ready building
material, found predominantly in hilly areas.
2.1 CLASSIFICATION OF ROCKS***
The building stones are obtained from the rocks which are classified in the following
three ways:
1. Geological classification1. Geological classification
2. Petrological (Physical)classification
3. Chemical classification
2.2 GEOLOGICAL CLASSIFICATION
Natural rocks can be classified according to their geological mode of formation as
1. Igneous rocks
2. Sedimentary rocks and
3. Metamorphic rocks.
15. DIFFERNCE BETWEEN TRADITIONAL AND
ORGANIC MATERIALS
TRADITIONAL MATERIALS
⢠Traditional materials are not
suspected to insert attacks.
⢠Regular inspection not required.
⢠No need of skilled workers to ensure
ORGANIC MATERIALS
⢠Organic construction materials are
suspected to insert attacks.
⢠It requires a regular inspections.
⢠Need skilled workers to ensure
proper construction
⢠Seepage of water is less
⢠Durability is more
⢠Cost of traditional materials is high.
proper construction.
⢠seepage of water will be more
⢠Durability is less
⢠cost of organic materials is less
17. 2.2.1 IGNEOUS ROCKS
The inside portion of the earthâs surface has high temperature causing the masses of
silicates to melt. The molten or pasty rocky material is known as the magma and this
magma occasionally tries to come out to the earthâs surface through cracks or weak
portions. The rocks which are formed by the cooling of magma are known as the
igneous rocks.
Magma formation
18.
19. The igneous rock are classified into three types
1. Plutonic rocks
2. Hypabyssal rocks
3. Volcanic rocks
Plutonic rocks:
Rocks formed due to cooling of magma at a considerable depth from the earthâs
surface. The cooling is slow and the rock possess coarsely grained crystalline
structure. The igneous rocks commonly used in building industry are of plutonic
type.
Ex:- GraniteEx:- Granite
Hypabyssal rocks:
Rocks formed due to cooling of magma at a relatively shallow depth from the
earthâs surface. The cooling is quick and hence these rocks possess finely grained
crystalline structure.
Ex: Dolerite
Volcanic rocks
Rocks formed due to pouring of magma at a earthâs surface. The cooling is very
rapid as compared to the previous two cases. Hence these rocks are extremely fine
grained in structure. They frequently contain some quantity of glass which is a non
crystalline material. Ex:- Basalt.
21. 2.2.2 SEDIMENTARY ROCKS
The rocks formed by the deposition of products of weathering on the pre-existing rocks.
All the products of weathering are ultimately carried away from their place of origin by
the agents of transport. Such agents are frost, rain, wind, flowing water etc..
Following four types of deposits occur:
a. Residual deposits
b. Sedimentary deposits
c. chemical deposits
d. Organic depositsd. Organic deposits
e. Residual deposits
Some portion of the products of weathering remain at the site of origin. Such
deposit is known as a residual deposits.
b. Sedimentary deposits
The insoluble products of weathering are carried away in suspension and when such
products are deposited, they give rise to the sedimentary deposits.
c. Chemical deposits
Material that is carried away in solution may be deposited by some physio-
chemical processes such as evaporation, precipitation etc... It gives to the chemical
deposits
22. d. Organic deposits
Some portion of the product of weathering gets deposited through the agency of
organisms such deposits are known as the organic deposits.
Ex :- sedimentary rocks are gravel, sand stone, limestone, gypsum and lignite etc
GRAVEL SAND STONE
LIGNITE
23. 2.2.3 METAMORPHIC ROCKS
The rocks formed by the change in character of the pre-existing rocks. The igneous
rocks as well as sedimentary rocks are changed in character when they are subjected to
great heat , pressure and earth movements. The process of change is known as the
metamorphism.
Ex:-slate, gneiss, schist, marble, quartzite and phyallite.
Four types of metamorphism:-
1. Thermal metamorphism:- Heat is the predominant factor in this type of1. Thermal metamorphism:- Heat is the predominant factor in this type of
metamorphism
2. Cataclastic metamorphism:- metamorphism brought about by pressure only.
3. Dynamo- thermal metamorphism:- if the metamorphism brought about by heat
and pressure.
4. Plutonic metamorphism:-The metamorphic changes at great depths are therfore
brought about by uniform pressure and heat. Such metamorphism is known as
plutonic metamorphism.
24. 2.3 PHYSICAL CLASSIFICATION
The classification based on general structure of rocks. According classification, the
rocks are of the following three types:
1. Stratified rocks
2. Unstratified rocks and
3. Foliated rocks
Stratified rocks:- The rocks possess planes of stratification or cleavage and such
rocks can easily be split up along these planes. The sedimentary rocks are distinctlyrocks can easily be split up along these planes. The sedimentary rocks are distinctly
stratified rocks.
25. 2. Unstratified rocks
These rocks are unstratified. The structure may be crystalline granular or compact
granular. The igneous rocks of volcanic agency and sedimentary rocks affected by
movements of the earth are of this type of rock.
3. FOLIATED ROCKS
These rocks have tendency to be split up in a definite direction only. The foliated
structure is very common in case of metamorphic rocks.
26. 2.4 CHEMICAL CLASSIFICATION
This classification is known as the scientific or engineering classification, the rocks are
of the following three types:
1. Silicious rocks:-
In these rock, silica predominates.
The rocks are hard and durable
Ex:-granites and quartzites
2. Argillaceous rocks:-2. Argillaceous rocks:-
In these rock, the argil or clay predominates
The rocks may be dense and compact or they may be soft.
These stones are hard and durable but brittle.
Ex:- Slates, laterites
3. Calcareous rocks:
In these rocks, the calcium carbonate predominates
Ex: limestone, marbles etc.
27. ROCK FORMING MINERALS
Monomineralic rock:- Rock contains only one mineral.
Ex:- Quartz sand, pure gypsum, magnesite etc:
Polymineralic rocks:- Rock contains several mineral.
Ex:- Basalt, granite etc...
Mineral indicates a natural occurring substance having definite chemical composition
and molecular structure.
Minerals in the igneous rocks:- Augite, chlorite, felspar, Hornblende, Mica, quartzMinerals in the igneous rocks:- Augite, chlorite, felspar, Hornblende, Mica, quartz
etc..
Minerals in sedimentary rocks: Calcite, Magnesite, dolomite, gypsum etc...
28. USES OF STONES
1. Structure:- The stones are used for foundations, walls, columns, lintels, arches,
roofs, floors, damp-proof courses etc...
2. Face-work:- Stones are adopted to give massive appearance to the structure.
3. Paving:- The stones are used to cover floor of buildings of various types such as
residential, commercial, industrial etc.. They are also adopted for paving roads,
footpaths. Etc..
4. Stones can be used for cement concrete, murum roads, hollow blocks etc...4. Stones can be used for cement concrete, murum roads, hollow blocks etc...
5. Miscellaneous:-
Ballast for railways
Construction of bridges, piers, abutments, retaining walls, dams etc..
30. QUALITIES OFA GOOD BUILDING STONE***
1. Crushing strength:- For good structural stone, the crushing strength should be
greater than 100N/mm².
2. Appearance:- The stones which are to be used for face work should be decent in
appearance and they should be capable of preserving their colour uniformly for a
long time. A good building stone should be uniform colour and free from holes,
spots, bands etc...
3. Durability :- A good building stone should be durable. It should withstand all
weathering actions which are alternate conditions of heat and cold, alternateweathering actions which are alternate conditions of heat and cold, alternate
conditions of wetness and dryness, chemical agencies , wind with high velocity
etc..
4. Facility of dressing:- The stones should be such that they can be easily carved,
moulded , cut and dressed.
5. Hardness (Resistance to penetration):- The coefficient of hardness, should be
greater than 17 for a stone to be used in road work. If it is between 14 and 17, the
stone is said to be of medium hardness. If it less than 14, the stone is said to be
poor hardness should not be used in road work.
31. 6. Resistance to Fire:- The Shape of stone should be such that it should preserved
when fire occurs. Argillaceous stones like limestone resists fire better than stones
containing quartz which expands at a temperature lower than 600áľC.
7. Specific gravity:- For a good building stone, specific gravity should be greater
than 2.7. The heavy stones are more compact and less porous and they can be used for
various engineering application such as dams, weirs, retaining walls etc... If stones are
to be used for domes, roof coverings the lighter varieties stones are preferred.
8. Toughness index (Resistance to impact force) :- In impact test, if the value of
toughness index comes below 13, the stone is not tough. If it comes between 13 andtoughness index comes below 13, the stone is not tough. If it comes between 13 and
19, the stone is said to be moderately tough. If it exceeds 19, the toughness of stone is
said to be high.
9. Water absorption :- For good stone, percentage absorption by weight after
24hours should not exceed 0.60%. If the water absorption is more it seriously affect
the durability of stones.
10. Weathering:- A good building stone should possess better weathering qualities. It
should be capable of withstanding adverse effects of various atmospheric and external
agencies such as rain, frost, wind etc...
32. STONE QUARRYING
The process of taking out stones from natural rock beds is known as the quarrying.
Methods of quarrying
1. Quarrying with hand tools
2. Quarrying with channeling machine
3. Quarrying with blasting.
1.Quarrying with hand tools:-
Three different ways
a. Digginga. Digging
b. Heating
c. Wedging
a. Digging
The stones are merely excavated with help of suitable instruments such as pick-axes,
hammers, showels, chisels etc...
This method is useful for soft stones.
Quarrying with Hand tools
34. b. Heating
In this method, the top surface of rock is heated. This usually done by placing pieces
of wood or by piling a heap of fuel over the surface and setting a steady fire to them
for some hours, this causes unequal expansion, the upper layer of rock separates out.
The detached portion of rock separates is then removed by suitable instruments such
as pick-axes, crowbars etc...
c. Wedging:-
In this method, if rock surface contains cracks or fissures, the steel wedges or points,
as shown in figure are driven through such cracks by means of hammers.
35. b. Quarrying with channeling machine
In this method, the channeling machines driven by steam, compressed air or electricity
are used to make vertical or oblique grooves on the rock mass. The wedges are driven
into holes and the block is then broken loose from its bed.
c. Quarrying by blasting
In this method, the explosives are used to convert rocks into small pieces of stones. This
method is adopted for quarrying hard stones, having no cracks.
36. DRESSING OF STONES***
The stones, after being quarried, are to be cut into suitable sizes and with suitable
surfaces. This process is known as the dressing of stones.
Dressing of stones is carried out for the following purposes:
1. To get the desired appearance from stone work
2. To make the transport from quarry easy and economical
3. To suit the requirements of stone masonry.
4. Stones obtained from the quarry are of irregular shape and size mostly not suitable
directly for building works hence dressing is required.
Varieties of finishes obtained by the dressing of stones:-Varieties of finishes obtained by the dressing of stones:-
1. Axed finish:- The surfaces of hard stones such as granite are dressed by means of
an axe. Such a finish is termed as an axed finish.
2. Boasted or droved finish :- In this type of finish, the boaster is used to make non-
continuous parallel marks on the stone surface as shown in fig.
37. Boaster (Chisel)
3. Dragged finish or combed finish3. Dragged finish or combed finish
In this type of finish, a drag or a comb, which is a piece of steel with a number of
teeth, is rubbed on the surface in all directions and surface. This finish is suitable
for soft stones only.
38. 4. Furrowed finish
In this type of finish, a margin of about 20mm width, is sunk on all the edges of stone
and the central portion is made to project about 15mm. A number of vertical or
horizontal groves about 10mm wide are formed in this projected portion.
5. Hammer dressed finish
In this type of finish, the stones are made roughly square or rectangular by means of
hammer.
39. 6. Reticulated finish
This type of finish presents a net like appearance. A margin about 20mm wide, is
marked on the edges of stone and irregular sinking are made on the enclosed space.
7. Polished finish:- The surface of the stones such as
marble, granites etc.. are polished with machines such
finish is polished finish.
8. Circular finish:- In this type of finish, the surface of
stone is made round or circular as in case of stone
columns.
Circular finish
40. MODERN OR MANUFACTURED BUILDING MATERIALS
⢠Modern building materials, are synthetic materials, which are made in industrial
settings such as plastic, plywood, brick, blocks etc..
BRICKS
The bricks are obtained by moulding clay in rectangular blocks of uniform size and then
by drying and burning of these blocks.
Clay bricks are mostly used for building up of interior and exterior walls.
41. COMPOSITION OF GOOD BRICK EARTH (CLAY)
Following are the constituents of good earth brick:
1. Alumina:- A good brick earth should contain about 20% to 30% of alumina. This
constituent imparts plasticity to the earth so that it can be moulded. If alumina is
present in excess, with inadequate quantity of sand, the raw bricks shrink and wrap
during drying and burning.
2. Silica:- A good brick earth should contain 50 % to 60 % of silica. The presence of
this constituent prevents cracking, shrinking and warping of raw bricks. It imparts
uniform shape to the bricks. The excess of silica destroys the cohesion between
particles and the bricks become brittle.
3. Lime:- A small quantity of lime not exceeding 5% is desirable in good brick earth.
The lime prevents shrinkage of raw bricks. The excess of lime causes the brick to melt
and hence its shape lost.
4. Oxide of Iron:- 5 to 6% is desirable in good brick earth. It helps as lime to fuse
sand. It also imparts red colour to the bricks. The excess of oxide of iron makes the
brick dark blue or blackish. If quantity less, the bricks will be yellowish in colour.
5. Magnesia:- A small quantity of magnesia in brick earth imparts yellow tint to the
bricks and decreases shrinkage. But excess of magnesia leads to the decay of bricks.
42. HARMFUL INGREDIENTS IN BRICK EARTH
1. Iron pyrites: If iron pyrites are present in brick earth, the bricks are disintegrated
during burning.
2. Alkalies:- Causes bricks to twist or warp and cause the efflorescence on the
surface of brick. The appearance of the building as a whole is then seriously
spoiled.
3. Pebbles:- The presence of pebbles is undesirable brick earth because it will not
allow the clay to be mixed uniformly and thoroughly which will result in weak
and porous brick.and porous brick.
4. Vegetation and organic matter:- The presence of vegetation and organic matter
in brick earth makes the brick porous.
5. Iron pyrites: The iron pyrites present in brick earth,
causes bricks to disintegrated during burning.
Efflorescence
43. MANUFACTURE OF BRICKS
In the process of manufacturing bricks, the following four distinct operations are
involved:
1. Preparation of brick earth (clay)
2. Moulding of bricks
3. Drying of bricks
4. Burning of bricks
1. Preparation of clay1. Preparation of clay
The clay for bricks is prepared in the following order:-
a. Unsoiling
b. Digging
c. Cleaning
d. Weathering
e. Blending
f. Tempering
44. a. Unsoiling:- The top layer of soil, about 200mm in depth, is taken out and thrown
away. The clay in top soil is full of impurities and hence it is to be rejected for the
purpose of preparing bricks.
b. Digging:-The clay is then dug out from the ground. It is spread on the leveled
ground.
c. Cleaning:- The clay, as obtained in the process of digging, should be cleaned of
stones, pebbles, vegetable matter etc..
d. Weathering:- The clay is then exposed to atmosphere for softening. The period
of exposure will be 1 month. This is done to develop homogeneity in the mass ofof exposure will be 1 month. This is done to develop homogeneity in the mass of
soil, particularly if they are from different sources, and also to eliminate the
impurities
e. Blending:- The clay is made loose and any other ingredient to be added to it, is
spread out at its top. Blending indicates mixing.
f. Tempering:- In the process of tempering, the water in required quantity is added
to clay and the whole mass is kneaded or pressed under the feet of man or cattle.
The tempering should be done to obtain homogeneous mass of clay.
For manufacturing bricks on large scale, the tempering is usually done in pug mill.
45. PUG MILL
The process of grinding clay with water and making it plastic is known as the
pugging.
⢠A pug mill consists of a conical iron tub with
cover at its top. It is fixed on a timber base.
⢠The bottom of tub is covered except for the hole
to take out pugged earth.
⢠The vertical shaft with horizontal arms is
provided at the center of iron tub.
⢠The long arms are fixed at the top of vertical
shaft to attach a pair of bullocks.
⢠The ramp is provided at bottom to collect the
pugged clay.
⢠In the beginning , the hole for pugged clay is
closed and clay with water is placed in pug mill
from the top. When the vertical shaft is rotated by
a pair of bullocks, the clay is thoroughly mixed up
by actions of horizontal arms.
The rotation of vertical shaft can also
be achieved by using steam, diesel or
electric power.
47. 2. Moulding
The clay which is prepared as above is then sent for the operation of moulding.
Moulding are two types:-
a. Hand moulding
b. Machine moulding.
a. Hand moulding
In hand moulding, the bricks are moulded by hand i.e. manually. The moulds are
rectangular boxes which are open at top and bottom. They may be of wood or steel.
Hand moulding are of two types:-Hand moulding are of two types:-
⢠Ground moulded bricks:- If bricks are moulded on level ground surface
⢠Table moulded bricks:- If bricks are moulded on table
Ground moulded bricks
Table moulded bricks
48. b. Machine moulding
The moulding may also be achieved by machines. It proves to be economical when
bricks in huge quantity are to be manufactured at the same spot in a short time.
49. 3. Drying
The damp bricks, if burnt, are likely to be cracked and distorted. Hence the moulded
bricks are dried before they are taken for the next operation burning. For drying, the
bricks are laid longitudinally in stacks of width equal to two bricks. A stack consists of
eight or ten rows.
The bricks in stacks should be arranged in such way that sufficient air space is left
between them for free circulation of air.
50. 4. Burning
The very important operation in the manufacture of bricks. Since it imparts hardness
and strength to the bricks and makes them dense and durable. The bricks should be
burnt properly. If bricks are overburnt, they will be brittle and hence break easily. If
they are underburnt, they will be soft and hence cannot carry loads.
Burning temperature should be 1100áľC. If it is more or less than 1100áľC the strength,
will not be achieved.
The burning of bricks is done either in clamps or kiln.
51. CLAMPS
The clamp are temporary structures and they are adopted to manufacture bricks on a
small scale.
Procedure
â˘In this method the bricks and fuel are placed in alternate
layers. The amount of fuel is reduced successively in the top
layers. Fuel may consists of grass, cow dung, wood etc..
⢠Each brick tier consists of 4â5 layers of bricks.
⢠After 30 per cent loading of the clamp, the fuel in the
lowest layer is fired and the remaining loading of bricks and
fuel is carried out speedily.
â˘The top and sides of the clamp are plastered with mud.
Then a coat of cowdung is given, which prevents the escape
of heat.
â˘The production of bricks is 2â3 lakhs and the process is
completed in six months. This process yields about 60 per
cent first class bricks.
52. Advantages
⢠The burning and cooling of bricks are
gradual in clamps. Hence the bricks
produced are tough and strong.
⢠The burning of bricks by clamps proves
to be cheap and economical.
⢠No skilled labour and supervision are
required for the construction and working
of clamps.of clamps.
Disadvantages
⢠The bricks are not regular shape
⢠It is very slow process.
⢠It is not possible to regulate fire in a clamp once it starts burning.
⢠The quality of bricks is not uniform. The bricks near bottom are over burnt and those
near sides and top are under burnt.
53. KILNS
A large oven which is used to burn bricks. The kilns are of two types:
1. Intermittent kiln
2. Continuous kiln e.g. Bullâs trench and Hoffmanâs kilns.
Intermittent kiln:- These kilns are intermittent (not
continuous) in operation which means that they are
loaded, fired, cooled and unloaded. Kilns may be
either in rectangular or circular.either in rectangular or circular.
Procedure
⢠The raw bricks are laid in rows of thickness equal
to 2 to 3 bricks and of height equal to 6 to 8 bricks. A
space of about 2 bricks is left between adjacent rows.
This space is utilized for placing fuel.
⢠An arch like opening is formed by projecting 4 to 5
rows of bricks.
⢠Kiln is covered by clay or earth.
54. ⢠In this method, fire can be regulated by opening and closing the iron sheet doors of the
fire holes and by controlling the supply of fuel.
⢠In this method, for the first three days, the firing is kept slow by proper manipulation
of fuels after that high fire is maintained for period of 48 to 60 hours.
⢠The kiln is allowed to cool down gradually for at least seven days and the bricks are
then taken out.
DisadvantagesDisadvantages
⢠The supply of bricks is not continuous.
⢠There is wastage of fuel heat as kiln is to be cooled down every time after burning.
⢠The quality of bricks is not uniform. The bricks near bottom are over burnt and those
near sides and top are under burnt.
56. CONTINUOUS KILN
These kilns are continuous in operation. This means that loading, firing, cooling and
unloading are carried out simultaneously in the kilns.
Three varieties of continuous kiln:-
1. Bullâs trench kiln
2. Hoffmanâs kiln
3. Tunnel kiln.
Bullâs trench kiln
⢠The kiln may be of rectangular, circular or oven shape in plan.⢠The kiln may be of rectangular, circular or oven shape in plan.
⢠The kiln is constructed in a trench (narrow hole dug in ground) excavated in
ground.
⢠The outer and inner walls are to be constructed by bricks. The openings are
generally provided in the outer walls for loading and unloading bricks.
⢠Iron plates are used to divide the kilns in suitable section (dampers) and regulate
the heat when required.
⢠The method is widely used in India.
57. Working
⢠If fire is started in zone 7 and chimneys are arranged near the side walls of zone 8.
chimneys are provided for even distribution of heat inside the kiln.
⢠Damper is incorporated at a certain distance along the width.
⢠Small holes 36 to 48mm are made at the top through which coal in form of powder
or small pieces is dropped.
⢠Hot gases from the burning zone 7 heat the dry bricks stacked in zone 8. As the
burning completes (24hrs) the holes which are made are closed and new holes areburning completes (24hrs) the holes which are made are closed and new holes are
made in next zone for introducing the fuel. The positions of dampers and chimneys are
alerted accordingly.
⢠Zone 7 which is burnt, cools and is unloaded and reloaded with dry and raw bricks.
Thus operation of the kiln is continuous.
60. Advantages:-
⢠Cost of fuel is less
⢠Supply of bricks is continuous
⢠High percentage of first class bricks are produced.
⢠As raw bricks are loaded in the kiln, the drying space is saved.
Disadvantages:-
⢠High initial cost
⢠Skilled person is essential
61. HOFFMANâS KILN
â˘The kiln is built above the ground and circular in shape.
⢠It is divided into a number of compartments or chambers. As a permanent roof is
provided, the kiln can even function during rainy reason.
⢠Hoffmanâs kiln consists of
a. main doors for loading and unloading of bricks.
b. Communicating doors which would act as fuels in open condition.
c. a radial flue connected with a central chimney
d. Fuel holes to drop a fuel in to chambers for burning the bricks.d. Fuel holes to drop a fuel in to chambers for burning the bricks.
⢠In this type of kiln, each chamber performs various functions which include:
Chamber 1- Loading
Chamber 2 to 5 â Drying and pre heating
Chamber 6 and 7- Burning
Chamber 8 to 11- cooling
Chamber 12- Unloading
65. QUALITIES OF GOOD BRICKS
⢠The bricks should be table moulded, well burnt in kilns, copper-coloured free from
cracks and with sharp and square edges. The colour should be uniform and bright.
⢠The bricks should be uniform in shape and should be of standard size (190mm x
90mm x 90mm).
⢠The bricks when broken, should show a bright homogeneous and uniform compact
structure free from voids.
⢠The brick should not absorb water more than 20% by weight for first class bricks⢠The brick should not absorb water more than 20% by weight for first class bricks
and 22 percent by weight for second class bricks, when soaked in water for a period
of 24hours.
⢠The bricks should be sufficiently hard. No impression should be left on brick surface,
when it is scratched with finger nail.
⢠The brick should not break into pieces when dropped flat on hard ground from a
height of about 1 meter.
⢠The bricks should have low thermal conductivity and they should be sound- proof.
66. ⢠The bricks, when soaked in water for 24 hrs, should not show deposits of white salts
when allowed to dry in shade.
⢠No brick should have the crushing strength below 5.50N/mm².
CLASSIFICATION OF BRICKS
The bricks can boardly be classified into two categories:-
⢠Unburnt or sundried bricks
⢠Burnt bricks
Burnt bricks classified into 4 types:-
⢠First class bricks
⢠Second class bricks
â˘Third class bricks
⢠Fourth class bricks
Unburnt or sundried bricks are dried with help of heat
recovered from sun after the process of moulding. These
bricks can only be used in the construction of temporary
and cheap structures.
67. First class bricks
⢠Bricks are table moulded and of standard shape and they are burnt in kilns.
⢠The surface and edges of the bricks are sharp, square, smooth and straight.
⢠The crushing strength of the brick should not be less than 10 N/mm².
⢠Water absorption should not be more than 20%.
â˘No impression should be left on the brick when a scratch is made by a finger nail.
Second class bricks
⢠Bricks are ground moulded and they are burnt in clamp.
⢠Surface is somewhat rough and shape is also slightly irrergular.⢠Surface is somewhat rough and shape is also slightly irrergular.
⢠Bricks have cracks and edges may not be sharp and uniform
â˘The crushing strength of the brick should not be less than 7 N/mm².
⢠Water absorption should not be more than 22%.
Third class bricks
⢠Bricks are not hard and they have rough surfaces with irregular and distorted
edges.
⢠Bricks has a light yellowish coloured (underburnt bricks).
⢠These bricks give dull sound when struck against each other.
68. Fourth class bricks
⢠These are over burnt bricks with irregular shape and dark colour.
⢠Fourth class bricks are brittle.
SIZE AND WEIGHT OF BRICKS
⢠A brick of standard size 190mm x 90mm x 90mm is recommended by the BIS
(Bureau of Indian standards).
⢠Non âmodular brick size 230mm x 110mm x 70mm can be used in construction
⢠With mortar thickness, the size of such a brick becomes 200 mm x 100 mm x 100
mm is known as nominal size of the modular brick.
⢠Average weight of a brick will be about 30 to 35N (3.5kg).
69. SHAPE OF BRICKS
⢠The ordinary bricks are rectangular solids.
⢠But sometimes the bricks are given different shapes to make them suitable for
particular type of construction. Following are such few shapes of bricks.:-
1. Bullnose brick:-
A brick moulded with a rounded angle is termed as a bullnose.
2. Hollow bricks
These are also know as the cellular or cavity bricks. These bricks are light in weight
about one âthird the weight of the ordinary brick of the same size.
70. 3. Perforated brick
These bricks contain cylindrical holes throughout their thickness. These bricks are light
in weight and they require less quantity of clay for their preparation.
4. Circular Bricks:
These bricks have internal and external faces curved to meet the requirement of the
particular curve and radius of the wall.
5. Channel bricks:-These bricks are moulded to the shape of a gutter or a channel .
These bricks are used to function as drains.
71. 6. Coping Bricks:- These bricks are manufactured in a variety of shapes to set the
thickness of the wall and are throated on the underside to throw off rain water.
7. Cownose bricks:- A brick moulded with a double bullnose on end is known as a
cownose.
72. CERAMIC MATERIALS/PRODUCTS
The term ceramics is used to indicate the potterâs art or articles made by the potter. The
ceramic products are broadly divided into the following three categories:-
⢠Clay products
⢠Refractories- is used to indicate substance that are able to resist high temperatures.
⢠Glass.
Potter
Glass Ceramics
The clay products which are employed in building industry are tiles, terra-cotta,
earthenwares, stonewares, porcelain and bricks.
73. Ceramic tiles
TERRA-COTTA
TILESTILES
The tiles may be defined as thin slabs of brick which are burnt in kiln.
The tiles can be classified in the following two groups
1. Common tiles- These tiles have different shapes and sizes. They are mainly
used for paving, flooring and roofing.
2. Encaustic tiles:- These tiles are used for decorative purposes in floors, walls,
ceilings and roofs.
74. COMMON TILES
1. Manufacture of common tiles
Four operations are involved in the process of manufacturing the common tiles:-
a. Preparation of clay
b. Moulding
c. Drying
d. Burning
a. Preparation of clay
⢠The selected clay is taken and is made from any impurity such as grit, pebbles etc..
Such clay is then pressed and converted into fine powder in pug mills.
⢠A large quantity of pure water is added to the powdered clay and it is well mixed in
a tank. The mixture is then allowed to stand quietly. The coarse heavy particles settle
at the bottom of tank. The fine particles are taken into other tanks and the water is
then allowed to dry off. The fine clay left after such process is used for manufacture
of tiles.
75. b. Moulding
The clay is placed in moulds which represent the pattern or shape in which the tile is to
be formed. The clay is pressed into such moulds and tiles are ready for drying when
clay is taken out of moulds.
The care should be taken to preserve the shape of tiles during the removal of moulds.
Moulding can be done with help of mechanical means (machines).
Moulds
76. c. Drying
The tiles, as they come out of moulds, are placed flat one above the other in suitable
number. After about 2 days, the irregularity of tiles due to warping is corrected with a
flat wooden mallet.
Wooden mallet
d. Burning
The tiles are then burnt in kilns. A typical kiln, known as the Sialkote kiln, for
accommodating about 30000 to 40000 tiles is shown in fig.
Continued.............
77. ⢠It is circular in shape and is protected by a shed.
⢠A layer of bricks is laid flat on the rows of long narrow
flues.
⢠The burning is brought about placing the firing wood
in these flues.
⢠Above the layer of bricks, the dried tiles are placed.
⢠The fire is gentle in the beginning. It removes
moisture. It is then raised to about 800áľC. It is slackenedmoisture. It is then raised to about 800áľC. It is slackened
(decrease) for a period of about 6 hours and again
raised to white heat, temperature being 1300áľC. This
temperature is maintained for a period of 3 hours.
⢠The fire is again slackened (gradually decreased in
intensity) for 6 hours, then increased once more to white
heat and kept steady for about 3 to 4 hours.
⢠The kiln is then gradually allowed to cool down. The
process of the burning tiles is completed in 72 hours.
78. CHARACTERISTICS OF A GOOD TILE
⢠It should be free from any cracks or bends.
⢠It should be sound, hard and durable.
⢠It should be well burnt.
⢠It should give a clear ringing sound when struck with hand or with one another or with
light hammer.
⢠It should give an even and compact structure when seen on its broken surface.
⢠it should possess uniform colour.
79. TYPES OF COMMON TILES
Depending upon the use to which the tiles are put, the following are their different types:-
⢠Drain tiles- tiles allow water to pass through their skeleton.
⢠Floor or paving tiles
⢠Roof tiles- Allahabad tiles, corrugated tiles, flat tiles, flemish tiles, guna tiles, mangalore tiles
etc..
Allahabad tiles
80. TERRA-COTTA
The terra means earth and cotta means baked. Hence the terra-cotta means the baked
earth. It is thus a type of earthenware or porous pottery made from local clays and
glazed with glazes containing galena.
For getting the glazed products, the glazed materials should be applied by brush
on terra âcoat products before they burnt.
Manufacturing process of terra-coat read from text book Rangwala
81. PROPERTIES OF CERAMIC MATERIALS
⢠They are strong and durable
⢠They have low ductility and low fracture strength
⢠They have high compressive and shear strength
⢠They have high modulus of elasticity.
⢠They have good resistance to corrosion
⢠They have low resistance to impact, low toughness and low tensile strength.
⢠They have good thermal insulation.
82. UTILISATION OF WASTES FOR ALTERNATIVE BUILDING MATERIALS
There are large number of industries, agricultural and mining- mineral wastes which can be
utilized in production of alternative building materials.
Industrial waste
⢠Flyash, phosphogypsum, blast furnace slag, silica fume, red mud etc,
⢠Among these industrial waste flyash occupied most prominent position.
1. Flyash:-
â˘Flyash is fine residue obtained from thermal power plants using powdered coal asâ˘Flyash is fine residue obtained from thermal power plants using powdered coal as
boiler fuel.
⢠This very fine industrial waste creates environmental pollution and disposal problems.
Hence it is collected in electrostatic precipitatorsâ and to use as building material.
⢠A thermal plant with 1000MW capacity of electric generation produces about 1.5MT
of flyash every year which is dumped over 100 hectares of land, causing infertility to
land.
⢠Flyash bricks, flyash light weight aggregate, Blended cement
84. 2. PHOSPHOGYPSUM:-
⢠Phosphogysum is an important by-product of phosphoric acid and fertiliser industry.
⢠Approximately five million tonnes of phosphogypsum is produced each year in India and
causes disposal and environmental problems.
⢠Flyash- lime-Gypsum (Fal-G) Bricks or concrete.
3. GGBS- Ground Granulated Blast Furnace slag.
⢠Blast furnace slag is a by product obtained while smelting iron ore in blast furnace. By melting
the iron ore at 1400-1600°C pig iron is produced and the floating impurities, containing mainlythe iron ore at 1400-1600°C pig iron is produced and the floating impurities, containing mainly
lime, silica and alumina forms the blast furnace slag. This slag is quenched with water for cooling
down and then its finely ground into powder.
⢠Blended cements, partial replacement for cement.
4. Silica fume
⢠It is produced as a by-product during the manufacture of silicon metal or ferrosilicon
alloys.
⢠can be used as Partial replacement for cement.
85. AGRICULTURAL WASTE
The major agricultural wastes which are available in the country in huge quantities can be used as
building materials which are:
1. Bagasse ash
2. Coconut pith
3. Rice hush ash
1. Bagasse /Bagasse ash
Bagasse is the waste fibrous waste residue from sugarcane processing. Due to its
fibrous components, bagasse can be utilised for insulation boards and building
wall panels.
Bagasse ash can be used in concrete production as partial replacement for cement.
BURN
Sugarcane Bagasse Bagasse ash
Bagasse ash can be used in concrete production as partial replacement for cement.
86. 2. Coconut pith (Coir Pith)
⢠Coir is the outside layer of husk that surrounds the shell of the coconut.
⢠Coir pith can be used for brick production for low cost housing
CoirCoir Bricks
3. Rice husk ash3. Rice husk ash
Rice milling industry generates a lot of rice husk during milling of paddy which
comes from the fields. This rice husk is burnt to produce a rice husk ash, can be used
for brick making.
RICE HUSK RICE HUSK ASH
BURN
Rice husk bricks
87. BUILDING MATERIALS FOR LOW COST HOUSING
To achieve low cost house following building materials can be used:-
1. AUTOCLAVED CALCIUM SILICATE BRICKS:-
Calcium silicate bricks are manufactured from a mixture of sand and /or a siliceous
waste (Fly ash) and a small proportion of lime which is mechanically pressed and
autoclaved, so that materials are chemically bonded by the action of steam under
pressure.
The bricks is a suitable for alternative walling materials, particularly in the areas where
sand and siliceous wastes (fly ash or GGBS- Ground granulated blast furnace slag).
The bricks can be used for where good quality of clay is not available for making the
burnt bricks.
Autoclave calcium silicate bricks
88. 2. STABILIZED MUD BLOCKS
⢠Stabilized mud blocks are manufactured by
compacting a wetted mixture of soil, sand and
stabilizer (cement/lime) in a machine into a high
density block. Such blocks are called as stabilized
mud blocks.
⢠Produced locally, with a natural resource and semi
skilled labour, almost without transport, no burning
of bricks , hence it is cost effective blocks
89. 3. FLYASH BRICKS
⢠Flyash brick is a building material, specifically masonry units, containing flyash and water.
⢠Flyash brick is low cost bricks, because flyash costs less has its industrial waste.
4. COIR BRICKS
â˘Coir is the outside layer of husk that surrounds the shell of the coconut.
⢠Coir pith can be used for brick production for low cost housing.
5.CEMENT WASTE SLAG BRICK
The main feature of this is that a lot of waste slag (GGBS) is utilized for making brick.
Raw materials required to manufacture brick is waste slag (80%) , aggregate and
bonding agent (20%).
Waste utilization in this brick is high ,it cost less can be used as low cost housing
material
90. 6. LIGHTWEIGHT CONCRETE BLOCK
These are blocks which are having cellular or cavity in them.
Hollow block helps in saving construction materials and
therefore use of hollow block reduces construction cost can be
considered as building material for low cost housing.
(Difference between block and brick(Difference between block and brick
A concrete masonry unit (block), either hollow or solid any one of the external dimension of
which is greater than the corresponding dimension of a brick as specified in IS : 3952-1978.
400 mm x 200 mm x 100 mm(4â) ,
400 mm x 200 mm x 150 mm (6â),
400 mm x 200 mm x 200mm (8â).
Standard Size of Blocks available in
market
91. SUSTAINABLE MATERIALS IN CONSTRUCTION
ďSustainable definition :- âMeeting the needs of the present without compromising
the ability of future generations to meet their own needsâ.
Sustainability principles
1. Reduce dependence upon fossil fuels, underground metals and minerals.
2. Reduce dependence upon synthetic chemicals and other unnatural substances.
3. Reduce encroachment upon nature.
4. Meet human needs fairly and efficiently.
ďA Building material is generally considered to be sustainable, when its use will lead toďA Building material is generally considered to be sustainable, when its use will lead to
one or more of the following:-
⢠Reduction green-house gas generation, which causes global warming.
⢠Reduction in the use of nonrenewable resources upon which our society depends
⢠Reduction in land, water or air pollution.
ďSustainable materials in construction provides an opportunity for more efficient use of
available resources, while creating healthier and more energy âefficient environment.
92. ďConcept is to create a sustainable environment through conservation of resources,
energy-efficiency, cost-effectiveness and low maintenance requirements through
construction product selection.
â˘Sustainable development great emphasis is being laid worldwide on waste utilisation.
⢠For sustainable development the awareness for utilisation of industrial and mining
wastes in the manufacture of building materials have also increased, thus there will be a
effective savings in natural resources, reduces the pollution and reduces the cost of
construction.
⢠Concrete, cement, blocks and bricks are being produced with flyash or slag content up⢠Concrete, cement, blocks and bricks are being produced with flyash or slag content up
to 65%.
⢠Bagasse and coir have been used in the manufacture of bricks and insulation boards.
⢠Construction and demolition waste is recycled to produce aggregates (recycled
aggregates), use of construction and demolition waste can lead to sustainable
development.
93. Sustainability pyramid
1. Prevention
2. Minimization
3. Reuse
1
2
Most
favored
option
4. Recycle
5. Energy
recovery
6. Disposal
3
4
2
5
6
option
Least
favored
option
