Bitumen is black semi solid heavy hydrocarbon  which by cool done of ambient temperature will convert to solid. With increase of temperature the bitumen will become semi solid and then liquid. Main content of bitumen us hydrocarbon with high molecular weight contenting oil, resin and asphalten.
bitumen penetration grades are hard penetration grade bitumen using as paving grade bitumen
suitable for road construction and repair also for the production of asphalt pavements with below
technical specification. This grade of bitumen is mainly used in the manufacture of hot mix
asphalt for bases and wearing courses.