Abstract:

To evaluate the effect of graphene content on the properties of SBS⁃modified asphalt mixture， SBS⁃modified asphalt was used as a raw material and graphene as a modifier to prepare asphalt composites with graphene contents of 0.1， 0.2， and 0.3 wt%. The properties of the resultant modified asphalt mixture were evaluated， and their high temperature stability， low temperature crack resistance， and water were investigated. The optimal addition amount of graphene was determined according to the radar map. The modification mechanism of graphene for the SBS⁃modified asphalt was analyzed through fluorescence sampling microscope and SEM. The results indicated that the penetration of the modified asphalt mixtures decreased significantly but their softening point increased significantly due to the presence of graphene. Moreover， their ductility also decreased remarkably. In terms of road performance， the addition of graphene significantly improved the rutting resistance of the SBS⁃modified asphalt mixtures， whereas their low temperature crack resistance and water stability were slightly reduced. The radar map test results indicated that the modified asphalt mixtures obtained the best comprehensive performance at a graphene content of 0.2 wt%. In the mixing process of the SBS⁃modified asphalt with graphene， a lamellar structure and a large specific surface area of graphene make it easy to mix with asphalt molecules. Meanwhile， SBS can insert into graphene during the mixing process， resulting in stable physical crosslinking and improving the performance of the SBS⁃modified asphalt mixtures accordingly.

Key words: road engineering, SBS/graphene modified asphalt, road performance, radar map, modification mechanism