Civil Engineering - Building Materials - Discussion

A class bricks produce metallic sound.
B class bricks are over burnt.
c class bricks are under burnt.

D is absolutely wrong. 2nd class brick is slightly over burnt. So, option A is the correct answer.

B option is Correct.

First class and Second Class, both produce metallic ringing sound because of hardness property.

Second class brick is slightly over burnt.

Dark brown/bluish colour is of Jahma bricks.

The answer should be D, the metallic ringing sound is for the first class brick.

These are also fully burnt and give a clear ringing sound when struck together. Slightly irregularities in shape, size or color are accepted.

Its compressive strength shall not be less than 70 kg/cm2 and absorption value should not be greater than 22 percent when soaked for 24 hours in water.

Slight difference in the structure on fractured surfaces is admissible.

Use: For exterior work when plastering is to be done. And can also be used for interior works but they may not be used for flooring.

Note : under burnt brick is 3rd class brick.

Second-class bricks are typically described as "well burnt" and produce a metallic sound when struck, meaning they are not "under burnt" despite potentially having a slightly rougher appearance and irregular edges compared to first-class bricks; they may be slightly darker in colour, but not necessarily "dark brown" across all variations.

First-class brick produces metallic sound and 2nd class brick produce full sound according to my concept D is the correct answer.

1st- gives metallic sound.
2nd- slightly over burnt or well burnt.
3rd- underburnt.

Jahma - Dark brown colour.

D is the right answer. I too agree.

I think Option D is correct.