Cement is the glue that binds aggregates together to form concrete - one of the key construction materials in use today. Concrete is the most consumed material on earth, second only to water, with three tonnes per year used for every person. Twice as much concrete is used in construction as all other building materials combined.
Cement is made from a mixture of calcium, silica, aluminium and iron. A high temperature kiln heats the raw materials, transforming them chemically into clinker. This grey, pebble-like material comprises the special compounds that give cement its binding properties. Clinker is then mixed with gypsum and ground to a fine powder to make cement.
Construction of a typical family home requires around 14 tonnes of cement, and a kilometer of freeway contains as much as 2,500 tonnes of cement. Varying the mix of cement, sand and aggregate enables concrete to be used in a range of applications. Products can be designed, coloured and shaped to accommodate a variety of environmental conditions, architectural requirements and to withstand a wide range of loads, stresses and impacts.
The pre-mixed concrete industry consumes the greatest volume of cement, using it in applications such as:
- concrete slabs and foundations for buildings, roads and bridges;
- precast panels, blocks and roofing tiles;
- fence posts, reservoirs and railway sleepers.
Cement is also used in bulk quantities in other diverse applications including:
- stabilisation of roads and rocky surfaces;
- backfill mining operations and casings in oil and gas wells
- renders, mortars and fibre board