Technical study on the Iranian Gilsonite as an additive for modification of asphalt binders used in pavement construction

In this research, effects of the Iranian natural bitumen (gilsonite) on two types of asphalt binders produced in the country with the performance grades of PG58-22 and PG64-22 were studied according to superpave performance grading (PG) system. Results of conducted tests on the modified asphalt binders with 4%, 8% and 12% gilsonite show that although addition of gilsonite to base bitumens can cause improvement in high performance temperature (HT) of mentioned bitumens, it has no positive impact on low performance temperature (LT) of them.