Bitumen by definition is, a variety of mixtures of hydrocarbons, derived from the refining of crude oil. It is a thermoplastic material and its stiffness is dependent on temperature. The temperature vs.
stiffness relationship of bitumen is dependent on the source of crude oil and the method of refining.
Main usage is road surfacing and water-proofing.
Bitumen is completely soluble in carbon disulphide (CS2), and has adhesive and water-proofing capabilities. It consists mainly of hydrocarbons and is typically made from about 80% carbon and 15% hydrogen, with balance amounts being oxygen, nitrogen and other trace particles. Penetration grade bitumen is commonly used in road surfacing, and minor industrial applications.
Penetration determines the hardness of bitumen by measuring the depth to which a standard loaded needle will vertically penetrate in 5 seconds, in a sample of bitumen maintained at a temperature of 25 degrees Celsius.