Bogue's Compounds MCQ with answer and solution

Concept

Cement compound responsible for early strength

Formula

NONE

Step-by-step solution

1. Tricalcium silicate (C3S) hydrates rapidly and contributes significantly to the early strength development of concrete. 2. Dicalcium silicate (C2S) hydrates slowly and is responsible for ultimate long-term strength. 3. Tricalcium aluminate (C3A) and Tetracalcium aluminoferrite (C4AF) contribute to setting rather than early structural strength. Answer: A

Explanation

Tricalcium silicate, or C3S, hydrates rapidly during the initial stages of mixing and is primarily responsible for the early strength development of concrete within the first week. It reacts with water to form calcium silicate hydrate gel, which provides initial structural integrity and hardness. In contrast, compounds like C2S hydrate much more slowly and contribute mainly to long-term strength.

Why the other options are wrong

B) C₂S is responsible for ultimate or long-term strength gain in concrete C) C₃A is responsible for initial set and rapid heat hydration. D) C₄AF contributes very little to strength and reacts rapidly with water.

Shortcut

C3S provides early strength, while C2S provides later ultimate strength.

Common mistake

Confusing C3S (responsible for early strength) with C2S, which contributes to long-term ultimate strength.