Cement and Concrete
The terms cement and concrete are often used interchangeably, but cement is actually an ingredient in concrete.
Concrete, which is the most widely used manufactured material on the planet, is a mixture of aggregates and paste. The aggregates are sand and gravel or crushed stone; the paste is water and portland cement. (Gravel and crushed stone are both small rocks. The difference is that gravel is broken down naturally, while crushed stone is broken down by a machine, i.e. a rock crusher.)
Cement comprises 10-15% of the concrete mix and is the key ingredient – the glue that holds concrete together. The cement and water harden and bind the aggregates into a rock-like mass. This hardening process continues for years meaning that concrete actually gets stronger as it gets older.
Cement is manufactured by heating a precise mixture of finely ground limestone, clay and sand in a rotating kiln to temperatures reaching 1450ºC. This results in the production of cement clinker, an intermediate product in the manufacture of cement. The cement clinker emerges from the kiln, is cooled, and is then finely ground to produce the powder we know as cement.
Cement has been manufactured in Brookfield, Colchester County, since 1965. A quarry onsite provides the necessary limestone.
The Brookfield cement plant with the limestone quarry in the background.
(Source: http://www.cement.org/cement-concrete-applications/concrete-materials)
