bricks and its properties ,history ,uses , pro & cons. , manufacturing

1. ​Bricks
by Jaiprakash & Neeraj
History of bricks:-
Bricks are one of oldest building materials. Bricks were first time found in turkey and jericho on
7000 BC .
The first bricks were sun dried mud bricks.Later fired bricks were found which were more
durable than mud bricks for using permanent building.
Type of morden bricks:-
1. Common Burnt clay/Mud Bricks
2. Sand lime Bricks (Calcium Silicate Bricks)
3. Concrete Bricks
4. Fly ash Bricks
5. AAC(Autoclaved aerated Concrete Bricks
Raw material for bricks :-
Common burnt clay/ mud bricks:-
● Mixture of loam, mud sand and water mixed with a binding material such as rice
husks or straw.
​Sand lime bricks:-
● Silica sand, quicklime and water
Concrete bricks
● Mixture of powdered portland cement, water, sand and gravel
​ Fly ash bricks:-
● Fly ash , sand/river sand or stone dust, sludge lime/ hydrated lime
gypsum/cement
​AAC bricks:-
● Fly ash or sand, limestone powder, cement, gypsum, aluminium powder/paste
Size & weight of bricks:-
Tradition/ normal size 230*110*70 mm^3
Normal weight 3 to 3.5 kg
Orientation of bricks:-
A bricks is given a classification based on how it is laid, and how the exposed face is oriented
relative to the face of finished wall.
● Stretcher or Stretching bricks :- A brick laid flat with its long narrow side exposed
● Heading or Heading bricks :- A brick laid flat with its width exposed
● Soldier :- A brick laid vertically with its long narrow side exposed

2. ● Sailor :- A brick laid vertically with the broad face of brick exposed
● Rowlock :- A brick laid on the long narrow side with the short end the brick exposed
● Shiner or Rowlock Stretcher :- A brick laid on the long narrow side with the broad face of
the bricks exposed
Properties of bricks:-
The following are the required properties of good bricks:
1. Durability​:- A good bricks should be able to resist the effects of weathering agencies like
temperature,rain etc.
2. Colour:​- colour should be uniform and bright.
3. Shape​:- bricks should have plane faces. They should have sharp and true right angled
corners and uniform in shape.
4. Size:​- bricks should be of standard sizes as prescribed by codes.
5. texture​ :- they should posses fine, dense and uniform texture. They should not possess
fissures,cavities,loose grit and unburnt lime.
6. Soundness:​- when struck with hammer or with another bricks, it should produce metallic
ringing sound.
7. Hardness ​:- the bricks should be sufficiently hard fingernail scratching should not
produce and impression on the bricks.
8. Strength​ ( IS code 4395 part 1) :- crushing strength of bricks should not be less than 3.5
N/mm^2.
9. Water absorpti​on (IS code 4395 part 2 ):- after immersing the bricks in the water for 24
hours, water absorption should not be more than 20% by weight for class-1 and 22% for
class-2.

3. 10. Efflorescence​ (IS code 4395 part 3) :- bricks should not show white patches when
soaked in water for 24 hours and then allowed to dry in shade. White patches ar due to
the presence of sulphate of calcium, magnesium and potassium.
11. Thermal conductivity​:- bricks should have low thermal conductivity, so that building built
with them are cool in summer and warm in winter.
12. Fire resistance​ :- fire resistance of bricks is usually good. In fact bricks are used to
encase steel columns to protect them from fire.
Use of bricks:-
​As a Structural unit since the clay bricks or burnt bricks are strong, hard , durable, resistive to
abrasion and fire, therefore
● They are used as a structure material in structures:-
1. Building
2. Bridges
3. Foundation
4. Pavement & Road
5. Tunnels or drains
● As an aesthetic unit or surface finish bricks of different colors, size and orientations are
used to get different surface design.
● Also used in landscaping, as facing bricks, as fire resistant material.
Advantage of bricks:-
1. Bricks is building material that has exceptional “thermal mass” properties like, the ability
to store heat and then slowly release it.
2. Clay bricks is sustainable green building material have countless recycling options.
3. Bricks are cheaper and lighter than normal concrete as well as RCC that reduce dead
load .
4. The bricks work needs only masons where as the concrete (RCC) needs carpenters,
fitters and masons apart from centering , shuttering material.
5. Raw material is easily available.
6. Good strength and surface texture.
Disadvantage of bricks:-
1. Less tensile strength
2. Bricks absorbs water easily so it causes fluorescence when not exposed to air
3. Rough surface of bricks may cause mould growth of not properly cleaned.
4. Can not used in high seismic zones.
Functions of constituents of brick earth:-
● Sand (Silica):-​ 50% to 60 %

4. Prevents shrinkage, cracking and warping of bricks . If silica content increases then
bricks become brittle.
● Clay (Alumina):​- 20% to 30%
Makes bricks plastic and lend hardness.
● Lime:- ​15%
Use a flux. Used in fine powder form prevents shrinkage, don’t use as lumps form
because volume expansion become high.
● Oxides of iron :- ​5% to 10%
Bricks show red colour due iron oxides but excess it of bricks show blue colour.
● Magnesia :-​ bricks show yellow colour, reduce shrinkage
Excess of magnesia decay property come in bricks.
Harmful Agent :-
● Stones and gravels
● Alkaline salts
● Limestone
● Organic matter
Manufacturing process of burnt clay bricks:-
1. ​Identification of suitable clay:-
● Field test:- ball test , Sedimentation test , soil shape test etc.
● Lab test : liquid limit , plastic limit ( IS 2720 )
2. ​Preparation of clay​ ( IS 2117:1975 )
● Unsoling
● Cleaning
● Weathering
● Tempering ( Add water for increase plasticity)
3. ​Moulding of clay :-
● Hand moulding
● Machine moulding
4. ​Drying of bricks:-
● Normal sunlight : 2 to 3 month
● Hot air dry : 2 weeks
5. ​Burning of bricks:-
● Temperature 900​˚C to 1200˚C
● By clamp or kiln ( intermittent or continuous )