Cement MCQ with answer and solution

Concept

Fineness of cement affects the rate of hydration; higher fineness leads to faster strength gain and greater shrinkage.

Step-by-step solution

1. Understand that fineness of cement measures the particle size and specific surface area. 2. Higher fineness means smaller particles and larger surface area available for chemical reaction with water. 3. Increased surface area accelerates the rate of hydration, leading to quicker setting and faster early strength development. 4. However, finer cement also requires more water for workability and results in higher drying shrinkage and potential cracking.

Explanation

Increasing the fineness of cement increases its surface area per unit mass. This exposes a larger area to water, accelerating hydration, which increases the rate of strength development, but it also leads to higher drying shrinkage and cracking tendencies.

Why the other options are wrong

A: Fineness increases, not reduces, the rate of strength development. B: While strength rate increases, the rate of deterioration typically increases or vulnerability to cracking increases due to higher shrinkage. C: Fineness decreases bleeding because finer particles hold water better, but it decreases (not increases) the rate of strength development is false.

Shortcut

Finer cement = Faster strength + Higher shrinkage.

Common mistake

Confusing early strength development with ultimate strength, or assuming finer cement decreases shrinkage.