Gypsum plays an important role in portland cement.
The construction industry uses both the natural and the synthetic forms of gypsum in Portland cement manufacturing, according to the University of Wisconsin. Although the amount of gypsum used in the mix represents a small percentage of the volume of all ingredients, gypsum has important functions.
Significance
The University of Washington calls Portland cement "the most widely used building material in the world." Production averages about 1.72 billion tons annually. Portland cement manufacturing involves adding either natural or FGD gypsum. Gypsum occurs naturally as a mineral or as a soft sedimentary rock. Synthetic gypsum comes from the byproducts of flue gas desulfurization (FGD) in coal powered plants.
Gypsum comprises about 3.5 percent of the weight of the dry materials in Portland cement. The other ingredients in the dry mix are calcium, silica, alumina and iron. Those dry materials provide the chemicals---tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite---that form reactions with water.
Control Hydration
Mixing dry Portland cement with water sets off a chain of chemical reactions. Tricalcium aluminate hydrates and hardens quickly. Adding gypsum to the mix prevents the concrete from hardening almost immediately after adding water.
Control Setting Time
Adding gypsum helps to control the amount of time it takes portland cement to cure, also known as the setting time for cement. According to Washington University, gypsum helps to affect the setting, or curing time of cement, to ensure it does not set too soon or take too long.
Related posts
Gypsum cement is a tough building material.Plasters and cements composed of gypsum have been used as building materials for thousands of years and are still used for walls, floors, surface finishe...
Gypsum is added to cement mixtures to slow the setting or drying time.Gypsum is a soft mineral that often appears in white or gray form. The mineral is soft enough that it can be scratched with ju...
Why Is Gypsum Added to Cement?The terms cement and concrete are used interchangeably, although cement is actually an ingredient of concrete. Gypsum is often added to cement and concrete to slow do...
Gypsum is used to slow the hardening process of cement.When working with concrete there are times when you need to slow the hardening process. Adding gypsum powder into the cement and water mixtur...
Cement is the binding ingredient in concrete.Portland cement is the main component of concrete and it is made using a highly evolved recipe of calcium, silicon, aluminum, iron, gypsum and other in...
