Bitumen is a mixture of
organic liquids that are highly
viscous, black, sticky, entirely soluble in
carbon disulfide, and composed primarily of highly condensed
polycyclic aromatic hydrocarbons.
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 has a consistency much like cold molasses.[1] Refined 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, boiling at 525&_160;°C (977&_160;°F).
The use of natural asphalt or mixtures thereof for waterproofing and as an adhesive dates at least to the fourth millennium B.C., when the Sumerians used it in statuary, mortaring brick walls, waterproofing baths and drains, in stair treads, and for shipbuilding. Other cultures such as Babylon, India, Persia, Egypt, and ancient Greece and Rome continued these uses, and in several cases the asphalt has continued to hold components securely together to this day. Though the existence of the structures have not been confirmed, it was reported that asphalt was used to bind the bricks of the Tower of Babel, and in a one-kilometer tunnel beneath the river Euphrates at Babylon in the time of Queen Semiramis (ca. 700 B.C.), where burnt bricks were covered with asphalt as a waterproofing agent.[2]
The Greek name for the substance was ?sp?a?t?? (asphaltos). Approximately 40 A.D. Dioscorides described production of asphalt (as distinguished from pissasphalt and naphtha) (1655 Goodyer translation)
