Asphalt concrete

Asphalt concrete (commonly called asphalt,^[1] blacktop, or pavement in North America, and tarmac or bitumen macadam in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams.^[2] Asphalt mixtures have been used in pavement construction since the nineteenth century.^[3] It consists of mineral aggregate bound together with bitumen (a substance also independently known as asphalt, Pitch, or Tar), laid in layers, and compacted.

The American English terms asphalt (or asphaltic) concrete, bituminous asphalt concrete, and bituminous mixture are typically used only in engineering and construction documents, which define concrete as any composite material composed of mineral aggregate adhered with a binder. The abbreviation, AC, is sometimes used for asphalt concrete but can also denote asphalt content or asphalt cement, referring to the liquid asphalt portion of the composite material.