Penetration value test on bitumen is a measure of hardness or consistency of bituminous material. For example: A 80/100 grade bitumen indicates that its penetration value lies between 80 & 100.

Penetration value is the vertical distance traversed or penetrated by the point of a standard needle into the bituminous material under specific conditions of load, time and temperature. This distance is measured in one tenths of a millimeter.

Penetration test is used for evaluating consistency of bitumen. It is not regarded as suitable for use in connection with the testing of road tar because of the high surface tension exhibited by these materials.

Penetration test on bitumen is carried to determine:

1. Consistency of bituminous material
2. Suitability of bitumen for use under different climatic conditions and various types of construction.