Cement

Key Specification:- Ordinary Portland cement (OPC) OPC, popularly known as grey cement, has 95 per cent clinker and 5 per cent gypsum and other materials.
The ASTM Standard Specification for Portland Cement (ASTM C150) provides for five types as follows :

• Type I—The standard product that has long been in use with no limitation on the proportions of the major oxides (CaO, SiO2, Al2O3, Fe2O3), also referred to as “ordinary Portland cement.”

• Type II—This cement possesses moderate resistance to sulfate attack because of certain limitations on composition. Sometimes called moderate-heat cement, it is intermediate between Type I and the low-heat Type IV cement. If moderate heat of hydration is desired, however, the optional limit on heat of hydration should be invoked when specifying or ordering.

• Type III—High-early-strength Portland cement is often produced by grinding Type I clinker finer or by altering the chemical composition of the cement.

• Type IV—Low-heat Portland cement. Not currently made in the United States and limited in production elsewhere.

• Type V—Sulfate-resisting Portland cement with appropriate limits on composition.