Basic Concepts for Civil Engineers for Interview and Campus preparation- Cement

The manufacture of cement consists of grinding the raw materials (calcareous and argillaceous stones consisting silica, alumina and iron oxide ) and mixing them intimately in a certain proportion. it is then burnt in a large rotary kiln at temeperature of 1500C, when the material sinters and partially fuses into balls known as clinker. The clinker is cooled and ground to fine powder with some gypsum added, and the resulting product is Commercial Portland cement.
The main Components of Cement are
 Lime - 63%
Silica - 22%
Alumina - 6%
Iron Oxide - 3%
Magnesium Oxide - 2.5%
Sulphur trioxide - 1.5%
Alkalies - 0.5%

 The lime, silica and iron oxide imparts strength to cement , while alumina gives quick setting property. The alkalies when in excess, causes efflorescence.

The Bougue's Components (Components of Cement Clinker)
Tri Calcium Silicate -C3S- 40%
Di Calcium Silicate - C2S- 32%
Tri Calcium Aluminate - C3A - 10.5%
Tetra Calcium Alumino Ferrite - C4AF- 9%