The main difference between Asphalt and Macadam is that the Asphalt is a sticky, black and highly viscous liquid or semi-solid form of petroleum; bitumen variety and Macadam is a type of road construction pioneered by Scottish engineer John Loudon McAdam.
Asphalt (), also known as bitumen (UK English: , US English: ) is a sticky, black, and highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term asphaltum was also used. The word is derived from the Ancient Greek ἄσφαλτος ásphaltos.
The primary use (70%) of asphalt is in road construction, where it is used as the glue or binder mixed with aggregate particles to create asphalt concrete. Its other main uses are for bituminous waterproofing products, including production of roofing felt and for sealing flat roofs.
The terms “asphalt” and “bitumen” are often used interchangeably to mean both natural and manufactured forms of the substance. In American English, “asphalt” (or “asphalt cement”) is commonly used for a refined residue from the distillation process of selected crude oils. Outside the United States, the product is often called “bitumen”, and geologists worldwide often prefer the term for the naturally occurring variety. Common colloquial usage often refers to various forms of asphalt as “tar”, as in the name of the La Brea Tar Pits.
Naturally occurring asphalt is sometimes specified by the term “crude bitumen”. Its viscosity is similar to that of cold molasses while the material obtained from the fractional distillation of crude oil boiling at 525 °C (977 °F) is sometimes referred to as “refined bitumen”. The Canadian province of Alberta has most of the world’s reserves of natural asphalt in the Athabasca oil sands, which cover 142,000 square kilometres (55,000 sq mi), an area larger than England.
Macadam is a type of road construction, pioneered by Scottish engineer John Loudon McAdam around 1820, in which single-sized crushed stone layers of small angular stones are placed in shallow lifts 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 binder to keep dust and stones together. The method simplified what had been considered state of the art at that point.
A sticky, black and highly viscous liquid or semi-solid, composed almost entirely of bitumen, that is present in most crude petroleums and in some natural deposits.
asphalt concrete, a hard ground covering used for roads and walkways.
To pave with asphalt.
The surface of a road consisting of layers of crushed stone (usually tar-coated for modern traffic).
Any road or street.
To cover or surface with macadam.
a mixture of dark bituminous pitch with sand or gravel, used for surfacing roads, flooring, roofing, etc.
the pitch used in asphalt, sometimes found in natural deposits but usually made by the distillation of crude oil.
surface with asphalt.
broken stone of even size, bound with tar or bitumen and used in successively compacted layers for surfacing roads and paths.