Question

By adding gypsum to cement:

• A. Reduce setting time to cement B.
• B. Produce very light colour cement.
• C. Increases setting time of cement
• D. A shining surface is formed.

Answer 1

The correct option is C

Increases setting time of cement

The explanation for the correct option.

1. During the manufacturing of cement, a small amount of gypsum is added during the final grinding process.
2. Gypsum controls the settling time of cement. It prevents the cement from immediate settling.
3. If gypsum is not added to cement, then cement settles very quickly when treated with water.
4. Once gypsum is added to cement, it increases the settling time of cement by decreasing the hydration process.

The explanation for the incorrect option.

1. The addition of gypsum does not affect the colour of cement increases.

2. The addition of gypsum doesn't affect shinning therefore, the other options A), B) and D) are wrong.

Since the addition of gypsum, increases the settling time of cement, therefore, option (C) is correct.