General facts about cement

Published on 30 January 2008 (updated on 13 February 2008)

Cement is mixed with chippings, sand, additives and water to produce concrete, of which it is the indispensable active ingredient.

For a long time researchers have been interested in the composition of a natural rock found at Portland, in England, which possessed remarkable hydraulic properties (i.e. the ability to harden in the presence of water). The enormous potential for the building industry if its production could ever be mastered was understood. The true structure of cement was discovered in the mid-nineteenth century by a Frenchman, Louis Vicat.
Cement is produced by heating a mixture of limestone and clay to a temperature of 1450°C. This produces hard nodules known as clinker.
Gypsum is added to the clinker which is then finely ground to give "Portland" cement. The addition of other minerals (for example blast furnace slag, power station ash, limestone fillers, natural or artificial pozzolans) produces different types of "additive" cement.
Cement is mixed with chippings, sand, additives and water to produce concrete, of which it is the indispensable active ingredient. It plays an essential role in contemporary construction and hence our living environment.

We live with cement on a daily basis.
It is a basic, omnipresent, and therefore essential part of life.
The extaordinary diversity of its uses makes it the material of the 21st century.