Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients. Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.
What Is Cement Made Of?
Cement is a powdery substance made up of four main compounds: calcium oxide, silicon dioxide, aluminum oxide, and iron oxide.
It is typically mixed with water and aggregate (sand, gravel, and crushed stone) to form concrete. The word “cement” is derived from the Latin word “caementum,” which means “stone–like.”
Portland cement, the most common type of cement, is made of a mixture of calcium, silicon, aluminum, and iron oxides. Calcium oxide (also known as lime) is the main ingredient.
It is produced by heating limestone (a type of calcium carbonate) in a kiln to a temperature of about 1,500 degrees Celsius. Silicon dioxide, aluminum oxide, and iron oxide are also present in small quantities.
The second most common type of cement is called pozzolanic cement. It is made of a mixture of calcium oxide and silica, with smaller amounts of aluminum oxide and iron oxide.
Pozzolanic cement is used in concrete that will be in contact with water, such as in dams, Aqueducts, and harbors. The third type of cement is hydraulic cement. It