BITUMEN

Bitumen, Ashalt and tar are referred as bituminous materials, which are fundamentally hydrocarbon materials. Asphalt is a combination of inert mineral matter lime, silica, lime alumina etc. and hydrocarbon also known as asphaltic bitumen. In some places like Bermudez and Trinidad asphalt is available in nature at a depth of 3 to 60 metres. It is called natural asphalt. General variety used all over the world is residual asphalt, which is obtained by fractional distillation of crude petroleum oil. Bitumen is the binding material, present in asphalt. It is a hydrocarbon. By partial distillation of crude oil it is obtained. It contains 87 %carbon, 11 % hydrogen and 2 %oxygen.

In the destructive distillation of coal, wood or other organic materials Tar is obtained. It yields volatile product and residue coke when coal or wood is heated to redness in a closed chamber. Volatile product gives tar after separating and cooling.

Comparison among asphalt, bitumen and tar is presented in given table.

              Comparison between asphalt, bitumen and tar