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Construction aggregate, or simply aggregate, is a broad category of coarse- to medium-grained particulate material used in construction. Traditionally, it includes natural materials such as sand, gravel, crushed stone. As with other types of aggregates, it is a component of composite materials, particularly concrete and asphalt.
Macadam is a type of road construction pioneered by Scottish engineer John Loudon McAdam around 1820, in which crushed stone is placed in shallow, convex layers and compacted thoroughly. A binding layer of stone dust (crushed stone from the original material) may form; it may also, after rolling, be covered with a cement or bituminous binder to ...
Substitutes for crushed stone used as construction aggregates include sand and gravel, iron and steel slag, sintered or expanded clay or shale, and perlite or vermiculite. [7] A crushed stone barge in China Crushed stone laid as a road base. Crushed stone is a high-volume, low-value commodity. The industry is highly competitive and is ...
A single concrete block, as used for construction. Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. . Concrete is the second-most-used substance in the world after water, [1] and is the most widely used building material
Gravel is an important commercial product, with a number of applications. Almost half of all gravel production is used as aggregate for concrete. Much of the rest is used for road construction, either in the road base or as the road surface (with or without asphalt or other binders.)
LECA was developed about 1917 in Kansas City, Missouri, to the production in a rotary kiln of a patented expanded aggregate known as Haydite which was used in the construction of SS Selma, an ocean-going ship launched in 1919. Following in the USA was the development of a series of aggregates known as Gravelite, Perlite, Rocklite, etc
Aggregates are generally added to increase the strength of composite materials. For example, the particles of stone used to make concrete typically include both sand and gravel. Many construction cement add in aggregates to increase its mechanical strength. [1] Aggregates make up 60-80% of the volume of concrete and 70-85% of the mass of concrete.
Most aggregate is used in construction, including 97 percent of sand and gravel and 76 percent of crushed rock. Per capita usage in the United States in 1996 was 8.7 metric tons per year. [7] Use, and therefore production of aggregate, is determined by the construction industry.