Cement

Cement is a complex mixture of aluminates and silicates of calcium. In 1824, a British Engineer, Joseph Aspidin made a binding material by mixing lime and silica and firstly it was named as 'portland cement'. The setting of cement is due to the hydration of calcium silicates and calcium aluminates. The mixture of cement, silica and water is called cement mortar. Concrete is reinforced by embedding steel in cement. A suitable site of a cement plant requires proximity to limestone and gypsum.

How is cement manufactured?

The raw materials (calcium carbonate, silica, alumina and iron ore) are ground into a fine powder and mixed in the fixed proportion. This is heated in a furnace at a high temperature (1500°C). Clinkers, which is a complex mixture of calcium silicate and calcium aluminate is formed. Gypsum is added to clinker and the mixture is powdered to make cement.

Cement and Concrete

Cement and Concrete are among the most important building materials. Cement is a fine, grey powder. To form concrete, it is mixed with water and other ingredients like crushed stone, sand, and gravel. As the concrete hardens, the cement and water combine to produce a paste that holds the other ingredients together. Concrete is easy to make, reasonably priced, waterproof, and fireproof. Nearly all the cements used today is portland cement, which is a Hydraulic cement or one that hardens under water. Portland cement is used chiefly to make concrete. Cement and concrete are used to make most of foundations for sky scrapers and big houses. Lime, Silicon, Aluminium, Magnesia, Iron oxide, Calcium Sulphate, Sulphur Trioxide and Alkaline are the chemical composition of cement.

Types of Cement

Cement is mainly classified into two types depending on the hardening and setting mechanism. These are Hydraulic Cement and Non-hydraulic Cement. Depending on the composition and characteristics, cement is classified into several types.