Bricks and Types of Bricks

 Bricks:- The Bricks may be defined as a uniformly burnt rectangular unit having high compressive strength.

BRICK

There are four type of bricks:-

1. First Class Bricks : As the name suggests these are of 1st quality. These bricks are well burnt having smooth and even surface. The shape of the brick is perfectly rectangular and the colour is uniformly reddish. The following properties should be there in first class brick :

(1) It should not give any mark when stretched with finger nail but should give metallic ringing sound when struck  with each other.

(2) Water absorption by weight should not exceed 20% and compressive strength should be more than 140 kg/cm²

(3) When broken into two pieces it should show a uniform and dense texture.

(4) The efflorescence should be nil or slight.

    These bricks are suitable for all type of structure. These are excellent for the exterior work, where plastering is not done. These  are also suitable for flooring.

2. Second Class Bricks : These bricks are slightly overburnt and not perfectly rectangular in shape. These are hard enough having rough surface. The colour of brick is uniform and should give metallic ringing sound when struck with each other. Water absorption should be more than 70 kg/cm² . These can show slight efflorescence.

    It is suitable for interior walls with plastering. These are not much suitable for flooring.

3. Third Class Bricks : These bricks are not properly burnt. The bricks may be under burnt or over burnt. The shape and size of these bricks is non uniform and colour is light red with yellow spots. Give dull sound when struck with each other. The compressive strength is below 70 kg/cm² and water absorption 23%. High or low efflorescence may be there.

    These are used for inferior or ordinary type of work where the rainfall is very low.

4. Jhama or Over Burnt Bricks : These are over burnt bricks with irregular in shape and size. They may get twisted due to over burning. The colour of these bricks are dark red or bluish. The water absorption is very low and compressive strength is high as of order of 150 kg/cm² 

.    These bricks are not useful for building construction, foundation works and floor subbases.