Multiple choice

The main ingredient in cement is

  1. gypsum

  2. clay

  3. limestone

  4. ash

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Limestone (calcium carbonate) is the primary ingredient in cement manufacturing. When limestone is heated with clay and gypsum in a kiln, it forms clinker, which is then ground to make cement. The calcium from limestone combines with silicon, aluminum, and iron from clay to form the cement compounds that harden when mixed with water.