Bitumen, also known as asphalt in the Canada and United States, is a mixture of dense, sticky, viscous organic liquids, mainly composed of polycyclic aromatic hydrocarbons, naturally occurring or obtained through the distillation of crude oil. It is black or brown in colour and possesses waterproofing and adhesive properties.
Naturally occurring or crude bitumen is a sticky, tar like form of petroleum which is so thick and heavy that it must be heated or diluted before it will flow. At room temperature, it is much like cold molasses. Naturally-occurring bitumen, sometimes also called natural asphalt, rock asphalt or oil sand, has been used as an adhesive, sealant and waterproofing agent for over 7,000 years. But it occurs only in small quantities and its properties are quite different from refined bitumen.