Aggregates MCQ with answer and solution

Concept

Classification of fine aggregates into four distinct grading zones (Zone I to IV) based on sieve analysis results.

Step-by-step solution

1. Refer to IS 383:2016 specification for coarse and fine aggregates. 2. Check the grading limits for fine aggregates based on standard IS sieves (10 mm down to 150 micron). 3. Fine aggregates are divided into four grading zones (Zone I, II, III, and IV) depending on the percentage passing specific sieves.

Explanation

According to IS 383:2016 (and earlier revisions like IS 383:1970), fine aggregates (sand) are classified into four grading zones: Zone I, Zone II, Zone III, and Zone IV, based on their particle size distribution. Zone I represents the coarsest sand, while Zone IV represents the finest sand.

Why the other options are wrong

A: Two grading zones is incorrect. B: Three grading zones is incorrect. D: Five grading zones is incorrect.

Shortcut

Remember the sequence: Fine aggregate grading has 4 zones, just like the number of main particle size ranges of interest in standard sand sieving.

Common mistake

Confusing the 4 grading zones of fine aggregates with the grading limits of coarse aggregates.