If the fineness modulus of sand is 3, then the sand is graded as
- AVery Fine Sand
- BFine Sand
- CMedium Sand
- DCoarse SandCorrect
Solution
Concept
Classification of sand by fineness modulus
Formula
NONE
Step-by-step solution
1. Fineness modulus (FM) of sand indicates the average size of particles in the aggregate. 2. Fine sand has FM between 2.2 and 2.6, medium sand has FM between 2.6 and 2.9, and coarse sand has FM between 2.9 and 3.2. 3. Since the given fineness modulus is 3, which falls between 2.9 and 3.2, it is graded as coarse sand. Answer: D
Explanation
Fineness modulus is a numerical index that indicates the coarseness or fineness of an aggregate. For fine sand, the fineness modulus ranges between 2.2 and 2.6, for medium sand between 2.6 and 2.9, and for coarse sand between 2.9 and 3.2. Because a value of 3 falls within the range of 2.9 to 3.2, the sand is graded as coarse sand.
Why the other options are wrong
A) Very fine sand typically has a fineness modulus below 2.2. B) Fine sand has a fineness modulus between 2.2 and 2.6. C) Medium sand has a fineness modulus between 2.6 and 2.9.
Shortcut
Sand Fineness Modulus ranges: Fine (2.2–2.6), Medium (2.6–2.9), and Coarse (2.9–3.2).
Common mistake
Confusing the fineness modulus range for coarse sand (2.9 to 3.2) with medium or fine sand ranges.
Correct answer: D) Coarse Sand