Bitumen, dense, highly viscous, petroleum-based hydrocarbon that is found in deposits such as oil sands and pitch lakes (natural bitumen) or is obtained as a residue of the distillation of crude oil (refined bitumen).
Bitumen is primarily used for industrial purposes. It can be found in the construction industry where it is used to make roads, which is why it is commonly called asphalt in this application. It also has waterproofing and adhesive properties, which makes it a good product for roofing.