Asphalt also known
as bitumen, is a sticky, black and highly viscous liquid or
semi-solid that is present in most crude petroleum and in some
natural deposits, it is a substance classed as a pitch.
The primary use of
asphalt is in road construction, where it is used as the glue or
binder mixed with aggregate particles to create asphalt concrete.
Its other main uses are for bituminous waterproofing products,
including production of roofing felt and for sealing flat
The terms asphalt
and bitumen are often used interchangeably to mean both natural and
manufactured forms of the substance. In American English, asphalt
(or asphalt cement) is the carefully refined residue from the
distillation process of selected crude oils. Outside the United
States, the product is often called bitumen. Naturally occurring
asphalt is sometimes specified by the term "crude Bitumen"; its
viscosity is similar to that of cold molasses. whilst the material
obtained from the fractional distillation of crude oil (boiling at
525 °C) is sometimes referred to as "refined bitumen".