Asphalt is a black hydrocarbon that occurs naturally and can be manufactured as part of the oil distillation process. Chemically quite similar to bitumen.
Asphalt generally refers to a mixture of mineral aggregate and bitumen (or tarmac in common parlance). Whilst tar refers to the black viscous material obtained from the destructive distillation of coal and is chemically distinct from bitumen.
Asphalt is sticky, black and highly viscous (Viscosity is a measure of the resistance of a fluid ) liquid or semi-solid that is present in most crude petroleums and in some natural deposits.
Asphalt is composed almost entirely of bitumen.
Bitumen is a mixture of organic liquids that are highly viscous, black, sticky, entirely soluble in carbon disulfide (carbon disulfide is a colourless liquid, which smells like chloroform), and composed primarily of highly condensed PAHs ( polycyclic aromatic hydrocarbons).
Bitumen is the residual (bottom) fraction obtained by fractional distillation of crude oil. It is the heaviest fraction and the one with the highest boiling point. Most bitumens contain sulphur and several heavy metals such as nickel, vanadium, lead, chromium, mercury and also arsenic, selenium and other toxic elements.
Asphalt is used in 2 main ways - as mastic asphalt for waterproofing, particularly on bridge decks, and as rolled asphalt (aka Hot Rolled Asphalt or HRA) for road and pavement surfacing.
Asphalt is also used as a generic term in Europe and North America to include all asphalts and bitumen coated materials.