Civil Engineering

1. SHREE DWARKESHO JAYATI
CONSTRUCTION MATERIALS
INTRODUCTION:
Variety of materials used for any building construction. Strength and stability of any building
is depending upon construction materials. Approximate 50% of total cost is the cost of
materials.
Construction materials are mainly divided into two parts.
Construction Materials
Naturally available Materials Artificial Materials (Manmade materials)
1. Timber 1. Cement
2. Clay or Soil or Earth 2. Lime
3. Fine Aggregates (sand) 3. Bricks
4. Gravels 4. Steel
5. Stones
6. Ceramics
7. Glass
8. Paints and Varnishes
9. Plastics
Bricks:
 Bricks are made of clay.
 It is rectangular in shape and of standard size.
Notes: 1. Brick is made of clay. Clay is molded to form rectangular block of standard
size, which are dried and then burnt into clamp or in a flame kiln.
Clamps: Both bricks and fuels are placed in alternate layers
Flame kilns: It is constructed with rectangular, circular or oval shape which may be
under ground or over ground.
 Composition of Bricks:
Alumina 20% to 30% Gives plasticity to the earth so it can
be mould
Silica 50% to 605 Prevents cracking, shrinking and
warping of raw bricks and impart
uniform shape
Lime <5% Prevents shrinkage of raw bricks
Iron oxide 5% to 6% Impart red colour to bricks
Magnesia 0.1% Impart yellow tint to bricks and
decrease shrinkage

2. SHREE DWARKESHO JAYATI
 Characteristics/ Requirements of Good Bricks:
1. It should be well burnt and of uniform colour (i.e. red or copper)
2. It should be of standard size and uniform in shape
3. It should be free from voids
4. When two bricks are struck with each other, it should gives metallic ringing
sound
5. It should not break or crushed in to pieces, when it dropped on flat ground
from 1.0m. height
6. It should be hard enough and when scratched by a finger nail, no impression
should be left on bricks surface
7. It should have crushing strength or compressive strength more than 5.5N/mm2
8. It should be sound proof and should have low thermal conductivity
9. The clay used for bricks should be free from organic matter, salts, pebbles etc.
10. It should be easily available and durable
 Properties of Good Bricks:
The properties of good brick can be derived from characteristics of a good
bricks
1. Bricks are manufactured from naturally available material like clay
2. Bricks are red or copper red in colour and having size of 19 cm* 9 cm* 9 cm.
3. Bricks are light in weight, durable, low cost materials and easily available
4. The weight of good bricks lies between 3.2 to 3.5 kg.
5. The density of good bricks vary from 16kN/m3 to 19kN/m3
6. Water absorption of good bricks shall not be more than 20%
7. Good bricks possess flexural strength more than 1.5N/mm2
8. Porous bricks conduct heat and sound at slower rate
 Types of bricks:
There are two types of bricks:
1. Conventional/ Traditional bricks: size 23 cm* 11.4 cm* 7.5 cm
2. Standard bricks: size 19 cm* 9 cm* 9 cm
Classification of Bricks
By manufacture By utility
a) Hand moulded a) 1st class bricks
b) Machine moulded b) 2nd class bricks
c) 3rd class bricks
d) 4th class bricks

3. SHREE DWARKESHO JAYATI
 1st class Bricks:
1. Bricks are sound, well burnt in kilns, rectangular with sharp edges
2. It is of best quality and used for superior work and exposed brick work
3. Compressive strength should not be less than 10N/mm2
 2nd class Bricks:
1. Bricks are burnt in clamps and grounded moulded
2. Surface is rough and shape is slightly irregular
3. Mainly used for ordinary work
4. Compressive strength should not less than 7N/mm2
 3rd class Bricks:
1. Bricks are burnt in clamps and grounded moulded
2. Surface is rough, irregular and distorted
3. Used for temporary work and less important work
 4th class Bricks:
1. Bricks are strong but over burnt
2. Surface is irregular and have dark colour
3. Used to prepare broken bats which are used in foundation concrete
 Uses of bricks:
1. Bricks are used for making wall for various building construction
2. Bats of bricks are used in foundation work
3. Bricks are used for canal lining, bridges piers, lintel etc.
 Importance of Bricks:
1. Bricks are used for making wall for various building construction
2. Bats of bricks are used in foundation work
3. Bricks are used for canal lining, bridges piers, lintel etc.
4. Bricks gives fire protection, sound/noise insulat ion and thermal insulation
5. Bricks are light in weight hence easy to handle
6. Bricks are cheap and easily available materials
Cement:
 Cement if defined as a binding material which bound various materials like sand,
aggregate etc. together and makes it as solid mass.
 It is obtained by burning a mixture of siliceous material (silica), argillaceous material
(clay), calcareous material (lime) in a proper proportion.
Notes: A mixture of silica, clay, lime, alumina, etc fed in to a rotary kiln in a wet
condition and burnt at a temperature around 15000c to 17000c. The clinker is than
cooled and ground into a fine powder. To control the setting time 2% to 3% gypsum

4. SHREE DWARKESHO JAYATI
is added at the time of grinding. The gray colour fine powder is than paced into a 50g
bags.
 Composition of cement:
Ingredients %
Ingredients
Function of ingredients
Lime(CaO) 60-65 Control strength and soundness
Silica(SiO2) 17-25 Provide strength
Alumina(Al2O3) 3-8 Cause quick setting of cement
Iron oxide 2-5 Impart grey colour to cement and
help in fusion of different ingredients
Magnesia(MgO) 0.5-4 Gives colour and hardness
Calcium
2-3 Control initial setting time
sulphate(CaSO4)
Sulphur 1-2 Imparts soundness to cement
Alkalis 0.5-1.3 Causes expansion and deterioration
of cement
 Characteristics/ Requirements of cement:
1. It should be of uniform grey colour and in powder form
2. It should be cool and smooth when rubbed between two fingers
3. It should not contain excess amount of ingredients
4. It should offer a good resistance against moisture, weathering effect
5. It should be free from any hard lumps
 Properties of cement:
1. It is in fine powder material of grey colour and considered as fine binding
material
2. It is easy to mix with sand, water and aggregate
3. It possesses good plasticity
4. It provides strength to masonry
5. It possesses good resistance against moisture and weathering effect
 Hydration of cement:
When water is added or mixed with cement, ingredients of cement chemically reacts
with the water, this chemical reaction between water and cement is known as
hydration of cement.

5. SHREE DWARKESHO JAYATI
The following compounds are formed during this process:
Compound % Function
Tricalcium silicate (C3S)
(3CaO, SiO2)
About
70% to
80% of
cement
contributed
Produce lots of heat and contribute
to develop a early strength of
cement (During first seven days)
Diacalcium silicate (C2S)
(2CaO, SiO2)
Hydrates slowly and contribute to
develop a later stage strength (28
days)
Tricalcium aluminate (C3A)
(3CaO, Al2O3)
14% Responsible for initial strength of
cement (24 hours). It is less stable
Tera-calcium alumino-ferrite
(C4AF)
(4CaO, Al2O3, Fe2O3)
10% to
15%
Less important
 Types of cement:
1. Ordinary Portland cement:
 This type of cement is widely used.
 It has medium hardening rate and heat generation due to that widely
used in major construction
 It offers resistance against shrinkage and cracking.
 When water is added in OPC, it reacts with water and generates four
major compounds (C3S), (C2S), (C3A) and (C4AF). [function of four
compound gives in above table]
2. Rapid hardening Portland cement:
 This type of cement gets a high early strength compare to OPC.
 Highly early strength is mainly due to C3S.
 Lime contain is more compare to OPC due to that large amount of heat
generated during hydration so it is not suitable for mass concrete.
 Cement sets rapidly so construction work carried out speedily and it
required short period of curing
 It is used in repairing of roads, bridges and concreting in cold weather.
3. Quick setting cement:
 The quick setting cement is produced by adding a small amount of
aluminum sulphate and by reducing % of gypsum.
 These types of cement start setting within five minutes after adding of
water and become hard within 30 minutes.
 It is finer than OPC.
 The addition of aluminium sulphate and fineness of grinding are
responsible for accelerating the setting time action
 It is used when concreting is to be done under water or running water.
4. Pozzuolana cement:
 Pozzuolana is a volcanic powder. This types of cement is
manufactured by uniformly blending of Portland cement with
Pozzuolana (10% to 30%)

6. SHREE DWARKESHO JAYATI
 The rate of development of strength of these types of cement is slower
than OPC hence it required longer curing period.
 It has no binding value itself but when mixed with cement it react with
excess lime and generate more stable compound and make it more
durable
 It has more resistance against chemical attack and therefore use for
marine works.
 It is also used in mass concrete like dams, weirs, bridges etc.
5. Blast furnace slag cement:
 About 60 to 70% of slag obtained from blast furnace is used to prepare
blast furnace cement
 Its strength in early days are less and hence it requires longer curing
period
 It is economical as slag (west product in the manufacturing process of
pig-iron is used) and durable but not suitable for dry acid zone.
6. Coloured cement:
 The cement of desired colour may be obtained by mixing 5% to 10%
minerals pigments with OPC.
 The coloured cement is widely used for finishing of floors, external
surfaces etc.
 The following are the pigments which gives desired colours.
Pigments Colour
Chromium oxide Green
Cobalt Blue
Iron oxide Brown, Red or Yellow according
to its proportion
Manganese dioxide Black or Brown
7. White cement:
 The raw materials used for this cement should be free from colouring
pigments.
 It is white in colour and it is used for floor finish, plaster work,
ornamental work etc.
 It is more costly than OPC
8. Low heat cement:
 In order to reduce amount of heat, this types of cement is used.
 This types of cement contains lower % of Tricalcium aluminate (C3A)
and Tricalcium silicate (C3S) and higher % of Diacalcium silicate
(C2S)
 This cement possesses less compressive strength.
 The initial setting time is about one hour and final setting time is about
10 hours.

7. SHREE DWARKESHO JAYATI
 It mainly used in mass concrete work.
9. Sulphate resisting cement:
 To increase a resistance against sulphates, Tricalcium silicate is kept
below 5% to 6%.
 This cement is used for structure like canal linings, culverts etc. which
are likely to be damaged by alkaline conditions.
 Uses of cement:
1. It is used as binding materials with different materials like sand, aggregate
etc.
2. It is used in cement mortar for masonry work, plastering work etc.
3. It is used to prepare cement concrete for various construction work
4. It is used in canal lining, construction of bridges, tunnels etc.
5. It is used for making joints for pipes, drains etc.
6. It is used in construction of water tanks, wells, precast pipes, watertight
floors
 Importance of cement:
1. It is an important binding material which binds sand particle to prepare
cement mortar and coarse aggregate and fine aggregate to prepare cement
concrete.
2. Cement mortar fill the joints of brick and stones
3. Cement paste use for smooth plastering work on various components