A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.
Cement powder, here conditioned[clarification needed] in bag, ready to be mixed with aggregates and water. Dispersing dry cement dust in the air should be avoided to prevent health issues.
Cement block construction examples from the Multiplex Manufacturing Company of Toledo, Ohio, in 1905
Clinker nodules produced by sintering at 1450 °C
Calcium oxide obtained by thermal decomposition of calcium carbonate at high temperature (above 825 °C).
Construction aggregate, or simply aggregate, is a broad category of coarse- to medium-grained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Aggregates are the most mined materials in the world. Aggregates are a component of composite materials such as concrete and asphalt; the aggregate serves as reinforcement to add strength to the overall composite material. Due to the relatively high hydraulic conductivity value as compared to most soils, aggregates are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and roadside edge drains. Aggregates are also used as base material under foundations, roads, and railroads. In other words, aggregates are used as a stable foundation or road/rail base with predictable, uniform properties, or as a low-cost extender that binds with more expensive cement or asphalt to form concrete. Although most kinds of aggregate require a form of binding agent, there are types of self-binding aggregate which require no form of binding agent.
A limestone quarry.
10 mm graded crushed basalt rock or aggregate, for use in concrete, called "blue metal" in Australia.
20 mm graded aggregate.
A gravel and sand extraction facility in Međimurje County, Croatia.