BRICK

1. .
BRICKS

2. Manufacturing of bricks
Operations involved
1. Preparation of clay
2. Moulding
3. Drying
4. burning

3. Burning of bricks
 In the process of burning, the dried bricks
are burned either in clamps (small scale)
or kilns (large scale) up to certain degree
temperature. In this stage, the bricks will
gain hardness and strength so it is
important stage in manufacturing of
bricks.

4. .
 The temperature required for burning is
about 1100oC. If they burnt beyond this
limit they will be brittle and easy to break.
If they burnt under this limit, they will not
gain full strength and there is a chance to
absorb moisture from the atmosphere.
 Hence burning should be done properly
to meet the requirements of good brick.

5. Burning of brick
1. Clamp burning
2. Kiln burning
-intermittent kiln
-continuous kiln

6. Clamp burning

7. .

8. Clamp burning
 Trapezoidal shape
 End raised at 15º from ground level
 Brick wall in mud at short end
 Alternate layers of raw bricks and fuels
 Fuels- grass, cow dung, wood
 Air circulation spaces are provided
 Total height of clamp 3 – 4 m

9. .
 Plastered with mud on sides and top, filled
with earth to prevent the escape of heat
 Burning period = 1to 2 months
 Cooling period =1 to 2 months
 Burning bricks are taken from the clamp

10. Advantages
 Tough and strong bricks
 burning and cooling are gradual
 Cheap and economical
 No skilled labour and supervision
required
 Saving of clamps fuel

11. Disadvantages
 Bricks are not of required shape
 It is very slow process
 It is not possible to regulate fire in a
clamp
 Quality of brick is not uniform

12. Kiln burning

13. 1.intermittent kiln

14. .
 A kiln is a large oven to burn bricks
 2-3 brick row
 Trolleys used for movement of bricks
 Loading of kiln with raw bricks
 Each door is built up with dry bricks and
are covered with mud or clay
 Fire period = 48 to 60 hours
 Cool period = 12 days
 Bricks are then taken out

15. Advantages of kiln burning
 Bricks are evenly burnt
 Performance of this kiln is better
 Suitable for burning of structural clay tiles,
terra cotta etc..

16. 2. Continuous kiln
 Bull’s trench kiln
 Hoffman’s kiln
 Tunnel kiln

17. Bull trench kiln
 Rectangular, circular or oval
 Trench excavated in ground
 Widely used kiln in India

18. Hoffman kiln
 Also called flame kiln
 Plan – circular shape
 Permanent roof provided
 Function in Rainy season also

19. plan

20. Tunnel kiln
 Form of a tunnel
 Straight, circular or oval
 Trolley transportation
 Large scale - economical

21. comparison

22. Characteristics of good brick
 Free from cracks and have sharp edges
 Uniform shape and size
 Should give clear ringing sound when
struck each other
 Compact and free from voids
 No impression when scratched
 Low thermal conductivity

23. ..
 Bricks should not absorb water when
soaked for 24 hours
 1st class → max = 20 percent by weight
 2nd class → max = 22 percent by weight
 When fall from 1 m height → should not
break
 Crushing strength > 55 kg/cm2
 Sound proof

24. .

25. IS specifications of bricks
 Unburnt bricks
 burnt bricks

26. Unburnt brick
 Sun dried bricks
 Used only in the constructions of
temporary and cheap structures
 Not suitable in Heavy rains

27. Burnt brick