Bricks - Basics, Viva Questions

1. The principal constituent of brick used as building materials are:

1. Alumina
2. Silica
3. Magnesia
4. Iron Oxide

2. The brick is made from clay with the above-mentioned constituents. Good soil for the manufacture of bricks is black cotton soil.

3. The principal constituent of brick is Alumina

4. A good brick will contain 50 to 60 % of silica, 20 to 30 % of alumina, 10% of lime and small quantities of iron oxide.

5. Iron oxide provides red color to the brick

6. Yellow color for the brick is provided by Magnesia

7. Frogs are identification marks left over the brick after the manufacture at a depth of 1 to 2cm. This act as a key for mortar.

8. Bricks can be classified as:

1. First class bricks
2. Second Class Bricks
3. Third Class Bricks

9. The crushing strength of First class bricks = 10.5N/mm2 ; Second Class Bricks = 7N/mm2 and Third Class Bricks = 3.5N/mm2

10. First class bricks are well burnt; Second class bricks produce a metallic sound when struck together. Third class bricks are underburnt and produce a dull sound when struck together.

11. Jhama bricks are those bricks which are overburnt

12. There are engineering bricks, common bricks, jhama bricks, and heavy duty bricks

13. If the compressive strength of bricks is greater than 40N/mm2 we call it as heavy bricks. 

14. The engineering bricks have compressive strength varying from 3.5 to 35N/mm2

15.The dimension of bricks:

1. Indian Standard Brick size = 19 x 9 x 9 cm
2. Indian Traditional Brick Size = 22.9 x 11.2 x 7 cm
3. Modular Size = 20 x10 x 10cm

16. The weight of brick ranges from 2.5 to 3.5kg

17. The minimum thickness of brick wall = 10cm. For load-bearing masonry wall thickness of 20cm is provided.

18. The water absorption capacity of bricks under 24 hr cold water immersion are:

1. First class bricks = 20%
2. Second Class Bricks = 22%
3. Third Class Bricks = 25%

19. Second class bricks are used for the construction of interior works

' 20. Hoffman's kiln is the most widely used kiln for brick manufacture. This is a continuous kiln where various operations are undertaken simultaneously.