Effects of SBS and different natural asphalts on the properties of bituminous binders and mixtures

• Effects of different natural asphalts on the properties of HMAs were compared.
• SBS modified mixtures also compared with natural asphalt modified mixtures.
• Control and modified mixtures were subjected to HMA performance tests.
• All modifiers increased to resistance to permanent strain and fatigue cracks.

In this study, three different natural asphalts (Trinidad Lake Asphalt, Iranian gilsonite and American gilsonite) and styrene–butadiene–styrene (SBS) were used as additive in bitumen modification. Results of binder tests showed that addition of 10.0% American gilsonite (MB10%AG), 9.5% Iranian gilsonite (MB9.5%IG), 60% Trinidad Lake Asphalt (TLA) (MB60%TLA) and 3.8% SBS (MB3.8%SBS) to pure bitumen (PG 58-34) achieved the desired performance level (PG 70-34). Experiments conducted on mixtures showed that mixtures prepared with MB60%TLA had the highest stiffness, stability, tensile strength and resistance to fatigue and permanent deformation. On the other hand, mixtures prepared with MB9.5%IG and MB3.8%SBS were observed to have highest resistance to moisture induced damage.