Bitumen is defined as "A viscous liquid ,or a solid ,consisting essentially of hydrocarbons and their derivatives, which is soluble in trichloro-ethylene and is substantially nonvolatile and softens gradually when heated". It is black or brown in color &possesses waterproofing and adhesive properties. It is obtained by refinery processes from petroleum ,and is also found as a natural deposit or as a component of naturally occurring asphalt, in which it is associated with mineral matte.