Portland cement clinker is ground to a fine powder and used as the binder in many cement products. A little gypsum is sometimes added. It may also be combined with other active ingredients or chemical admixtures to produce other types of cement including: ground granulated blast furnace slag cement
• Portland Cement is manufactured from limestone and shale rocks that have been fired at 1450 C to form a synthetic rock called clinker. This clinker is then crushed to a powder. • When limestone is heated, it gives off CO 2
Clinker, combined with additives and ground into a fine powder, is used as a binder in cement products. Different substances are added to achieve specific properties in the produced cement. Gypsum added to and ground with clinker regulates the setting time and gives the most important property of cement, compressive strength.
15.3.1 Make-up of Portland cement Portland cement is a fine powder produced by grinding Portland cement clinker (more than 90%), a limited amount of gypsum (calcium sulphate dehydrate – CaSO4.2H2O, which controls the set time) and other minor constituents which can be used to vary the properties of the final cement.
Cement is made by grinding clinker—the main energy intensive ingredient—to a fine powder. Producers know that replacing some of the clinker in portland cement with ground limestone offers benefits, the most important being that it reduces the embodied CO2 of the cement.
The clinker is ground to a fine powder in a cement mill and mixed with gypsum to create cement. The powdered cement is then mixed with water and aggregates to form concrete that is used in construction. Clinker quality depends on material composition, which has to be closely monitored to ensure the quality of the cement. Excess free lime .