Which of the following statements is correct for the selection of sand for masonry mortars? i. In natural sand, clay, fine silt and fine dust should be not more than 5% by mass ii. In crushed stone sand, clay, fine silt and fine dust should be not more than 5% by mass iii. Various sizes of particles of sand should be uniformly distributed throughout the mass
- AOnly (i)
- B(i) and (ii)
- C(ii) and (iii)
- D(i), (ii) and (iii)Correct
Solution
Concept
Requirements of sand for masonry mortar (IS 2116)
Step-by-step solution
1. IS 2116 limits clay, fine silt and fine dust to 5% in natural sand and 5% (as per the question) in crushed sand. 2. Sand should be well graded, with particle sizes uniformly distributed. 3. All three statements are correct.
Explanation
Clean, well-graded sand gives workable and strong mortar.
Why the other options are wrong
Options with fewer statements omit a correct statement.
Shortcut
All three.
Correct answer: D) (i), (ii) and (iii)