Bitumen penetration grade 40/50 is hard penetration grade bitumen using as paving grade bitumen suitable for road construction and repair also for the production of asphalt pavements. This grade of bitumen is mainly used in the manufacture of hot mix asphalt for bases and wearing courses. Penetration grade bitumen is pure petroleum grade bitumen, manufactured from vacuum bottom by passing hot air. This bitumen is produced from remain of crude oil after cracking and removing hydrocarbon. Penetration grade bitumen 40/50 has penetration between 40~ 50 desi-millimeters and softening point between 52 ~ 60C. The penetration grade bitumen 40/50 has a thermoplastic property which is like as synthetic resin material which gets softer with heating and hardens when cooled. This grade of bitumen 40/50 has very strong viscosity compare to other grades.