Question

In Bogues compounds, the main characteristic role of $C_{2}S$ is ________

• A. high heat of hydration
• B. low heat of hydration
• C. initial setting of cement
• D. early strength development

Answer 1

The correct option is B low heat of hydration

The main characteristic role of C${}_2$S is low heat of hydration.
(1) Tricalcium silicate (C${}_3$S) (25 - 50 %) - Normally 40%
Best cementing material and is well burnt
It is responsible for early hardness and strength, mainly 7 days of strength.
(2) Dicalcium silicate $\left(C_{2}S\right)(25-40$
It is responsible for ultimate strength.
It imparts resistance to chemical attack.
(3) Tricalcium Aluminate $\left(C_{3}A\right)$
It rapidly reacts with water and is responsible for flash set.
Mainly responsible for the initial setting.
(4) Tetracalcium Alumino ferrite $C_{4}AF)$ Poorest cementing value.