Concrete 101

Concrete is made when binding together particles of sand and gravel, stone, broken brick etc.  When water is added to the cement hydration takes place causing the whole mixture to set and harden forming a solid, rock-like mass.

The sand, gravel, broken stone etc. is the “aggregate”, sand – the “fine aggregate” and gravel as “coarse aggregate”.  The properties vary of course depending on the type of work done.

Sufficient water should be used to enable hydration to take place and to make the mixture easily workable but any excess is detrimental to the strength of the concrete.

When setting the wet concrete in the desired position it should be well rammed or tamped to consolidate it thoroughly and obtain a dense mixture which will eventually form a rock-like mass with no apparent voids.