In the bricks, when tested in accordance with the procedure laid down in IS 3495 (Part 2) : 1992, after immersion in cold water for 24 hours, water absorption shall not be more than i. 20 percent by weight upto class 12.5 ii. 15 percent by weight for classes higher than 12.5
- AOnly (i)
- BOnly (ii)
- CBoth (i) and (ii)Correct
- DNeither (i) nor (ii)
Solution
Concept
Water absorption limits for bricks
Formula
NONE
Step-by-step solution
1. Water absorption testing of standard clay bricks is conducted per IS 3495 (Part 2) after 24-hour immersion in cold water. 2. Permissible limits specify maximum water absorption percentages relative to the brick strength class. Answer: C
Explanation
According to IS 3495 requirements, common burnt clay bricks up to class 12.5 must not absorb more than 20% water by weight after 24 hours of cold water immersion. For higher strength classes above 12.5, the permissible water absorption limit is reduced to 15% by weight. Since both specified conditions are accurate standard provisions, option C is correct.
Why the other options are wrong
A) Statement (i) is incorrect regarding the water absorption threshold for class 12.5 bricks. D) Statement (ii) is true because water absorption should not exceed 15 percent for classes higher than 12.5.
Shortcut
Brick water absorption: ≤ 20% for class ≤ 12.5, ≤ 15% for class > 12.5 (both statements are true).
Common mistake
Selecting option A or B by misremembering the specific water absorption percentage limits for different brick classes.
Correct answer: C) Both (i) and (ii)