Investigation of Reological Properties of Pure Bitumen Modified With Gilsonite

The modifying of the rheological properties of pure bitumen to improve the performance of Asphalt mixtures has attracted many researchers in recent decades. The purpose of this study is to investigate the effect of Gilsonit on rheological properties of pure bitumen .For this purpose, different percentages of Gilsonite powder were used to modify the rheological properties of pure bitumen 60/70 .In the study of rheology of bitumen (modified and unmodified), viscosity test, softening point, penetration test and flash point were performed, in addition to, the thermal sensitivity of the bitumen was calculated. The results of this study indicate that the addition of Gilsonite to pure bitumen increases the viscosity and softening point and the penetration index of bitumen decreased. Also, Gilsonite improves the thermal sensitivity of pure bitumen, but this bitumen powder has no effect on the flash point. Gilsonite and bitumen used in this research are from the mine of Ilam province and the Pasargad oil refinery, respectively.