Aggregate size nomenclature – coarse, fine, silt, and clay bands Which of the following statements about standard particle size bands is correct for construction materials classification?

Introduction / Context:
Correctly classifying particle sizes is foundational for concrete mix design, soil mechanics, and pavement engineering. The boundary sieves distinguish fines from sands and gravels, while very fine fractions are further separated into silt and clay ranges based on behaviour and size.

Given Data / Assumptions:

• Indian Standard/commonly used size boundaries in construction engineering.
• Emphasis on practical sieve sizes (4.75 mm and 0.075 mm) and geotechnical size bands.
• Ranges are approximate and context-dependent but widely adopted.

Concept / Approach:
Coarse aggregate is generally material retained on the 4.75 mm sieve; upper maximum nominal size may be 20, 40, or up to 75 mm depending on design. Fine aggregate is sand fraction passing 4.75 mm and retained above 0.075 mm (75 microns). In soil mechanics, silt comprises particles roughly from 0.06 mm down to 0.002 mm; clay is finer than 0.002 mm and exhibits plasticity due to plate-like mineralogy.

Step-by-Step Solution:
Check (a): matches coarse aggregate nomenclature (retained on 4.75 mm; max often up to 75 mm).Check (b): fine aggregate band between 4.75 mm and 0.075 mm is standard.Check (c) and (d): geotechnical bands for silt and clay are consistent with common classification systems.Therefore, all statements are correct.

Verification / Alternative check:
IS 383 for aggregates and soil classification charts in geotechnical references corroborate these boundary values.

Why Other Options Are Wrong:
Each of (a)–(d) is valid; hence the inclusive choice (e) is correct.

Common Pitfalls:
Confusing the 0.075 mm limit (fines) with 0.05 or 0.06 mm used in some systems; remember that 75 microns is the standard sieve in concrete aggregate classification.

Final Answer:
All of the above