Bitumen

Published February 2000

In roofing, a class of amorphous, black or dark-colored (solid, semisolid or viscous) cementitious substances, natural or manufactured, that are composed principally of high molecular weight hydrocarbons and are soluble in carbon disulfide. Bitumens are found in asphalts, tars, pitches and asphaltites. The term can also be used generically to denote any material composed principally of bitumen. In the roofing industry, there are two basic bitumens: asphalt and coal-tar pitch. Before application, they are either heated to a liquid state, dissolved in a solvent or emulsified. See also Modified Bitumens.