Aggregates MCQ with answer and solution

Concept

Cause of bulking of sand

Formula

NONE

Step-by-step solution

1. Moisture content forms a thin film of water around fine aggregate particles. 2. Surface tension of this water film holds the sand particles apart, increasing the overall volume of the sand mass. 3. Therefore, bulking of sand is caused due to surface moisture. Answer: A

Explanation

Bulking of sand occurs when moisture forms a thin film of water around individual sand particles, creating surface tension that pushes the grains apart. This surface tension holds the grains in an expanded state, thereby increasing the overall volume of the fine aggregate. When sand is completely saturated or completely dry, this film effect disappears and the volume normalizes.

Why the other options are wrong

B) Air voids affect the porosity of sand but do not cause its volume expansion. C) Viscosity is a fluid property and is unrelated to sand bulking. D) Clay content affects the plasticity and workability of soil rather than sand bulking.

Shortcut

Bulking of sand is caused by Surface moisture creating surface tension.

Common mistake

Assuming bulking of sand is caused by clay content or air voids rather than surface moisture tension.