Portland cement is a finely ground, manufactured mineral product that when combined with water, sand, gravel and other materials forms concrete, the most widely used construction material in the world. Remember, cement is the glue that holds together the sand and gravel to make concrete. Its manufacture consists of the mining of limestone and small amounts of clay and silica, followed by crushing and burning in a kiln, with the rate of firing depending on the slope and rotational velocity of the kiln. As the materials move through the kiln, they are heated to about 2700 degrees and calcined, or chemically converted into small, grayish-black pellets of cement called clinker.
Clinker has no other use than for the production of cement.
Only then it is called cement. Cement Type Description Type II Standard cement used in the Southwestern U.S., which compared to Type I, produces less heat in the hydration process and is somewhat sulfate resistant . This is a modified Type II cement that generates high early strengths. Type V Cement used where lower heat of hydration is required and it is more resistant to sulfates. It is often used in marine and waste disposal applications.