Gypsum

Definition of Gypsum
Noun

Construction

1. A natural mineral, di-hydrated calcium sulfate, that is added to clinker in the finish milling circuit. (see additive). Gypsum helps control the rate at which concrete hardens by slowing down the hydration reactions. The slower rate gives concrete finishers enough time to work the plastic concrete before it hardens. Cement plants can also add synthetic gypsum, a recycled byproduct from the electric power industry, to control the set time in its finished products.