Description

Bitumen is the sticky, black and highly viscous liquid or semi-solid present in most crude petroleum and in some natural deposits; it is a substance classed as a pitch. Until the *0th century, the term asphaltum was also used.

Asphalt or bitumen can sometimes be confused with "tar", which is a similar black, thermoplastic material produced by the destructive distillation of coal. During the early and mid**0th century when town gas was produced, tar was a readily available product and extensively used as the binder for road aggregates. The addition of tar to macadam roads led to the word tarmac, which is now used in common parlance to refer to road-making materials.