7 Characteristics of Second Class Bricks
Following are the 7 characteristics of a second class brick:
1. Second class bricks are burnt in kilns.
2. The crushing strength of a second class brick should not be less than 7 N/mm2.
3. They are rectangular in shape.
4. They are free from cracks but small cracks and distortions are permitted.
5. Dry second class bricks should not absorb water more than 22% of their own weight when immersed in water for 24 hours.
6. They emit a ringing sound when two bricks are struck each other.
7. They are light red colour, but the colour of the brick is not same throughout the area.