A Comparative Study on the Physical and Rheological Properties of 60/70 and 80/100 Penetration Grade Bitumen in Malaysia

The engineering properties of a bitumen plays vital role in determining the suitability of the bitumen usage for a pavement structure. Presently, bituminous pavements in Malaysia are constantly subjected to high-speed loading of vehicles as well as increased pavement temperature due to extreme solar heat which causes rutting and fatigue failure issues. In this research, the 60/70 and 80/100 penetration grade bitumen were subjected to both physical and rheological testing. Physical testing was used to determine the softening point, ductility, penetration and penetration index value whereas rheological testing chiefly determined the engineering properties of the bitumen such as complex modulus and phase angle which interprets the stiffness and viscoelastic behavior. Physical testing results indicate that the 60/70 penetration grade bitumen possesses lower penetration value, higher softening point, adequate ductility and higher penetration index value compared to the 80/100 penetration grade bitumen. Besides, rheological results show that the complex modulus and rutting factor of 60/70 bitumen indicates good stiffness towards temperature rise compared to the 80/100 penetration grade bitumen, thus, posing better resistance towards permanent deformation. Additionally, the 60/70 penetration grade bitumen generally possesses better elasticity compared to the 80/100 penetration grade bitumen which is observed through the phase angle determination.