Bitumen
Bitumen is an immensely viscous constituent of petroleum. Depending on its exact composition it can bea sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In the U.S., the material is commonly referred to as asphalt. Whether found in natural deposits or refinedfrom petroleum, the substance is classed as a pitch
70% of annual bitumen production destined for road construction, its primary use. In this application bitumen is used to bind aggregate particles like gravel and forms a substance referred to as asphalt concrete, which is colloquially termed asphalt. Its other main uses lie in bituminous waterproofing products, such as roofing felt and roof sealant.
