Question

A quick-setting cement has an initial setting time of about

• A. 50 minutes
• B. 40 minutes
• C. 15 minutes
• D. 5 minutes

Answer 1

The correct option is D 5 minutes

Quick setting cement is produced by adding a small percentage of aluminium sulphate and by finely grinding the cement. The percentage of gypsum or retarder for setting action is also greatly reduced. The addition of aluminium sulphate and fineness of grinding are responsible for accelerating the setting action of cement. The setting of cement starts within 5 minutes after addition of water and it becomes hard like stone in less than 30 minutes or so.