Weathering characteristics of asphalt modified by hybrid of micro-nano tire rubber and SBS

Tire rubber has been considered as the ideal candidate for improving aging durability of styrene–butadienestyrene copolymers (SBS) modified asphalt pavement. However, crosslink characteristic of tire rubber affected its dispersion in SBS modified asphalt binder (SMB) and restricted high addition dosage. In this study, microscale and nanoscale tire rubber (MNTR) hybridized SMB with the high dosage was prepared for studying its structural evolution during weathering and physical property variation. Results of gel permeation chromatography and infrared spectroscopy showed that MNTR stabilized the molecular weight distribution and decreased oxidative condensation reaction of asphalt matrix during weathering, and yet did not prevent the SBS degradation. Structural characteristics revealed that the dissolved rubber and core–shell structured carbon black nanoparticles in MNTR were implanted into the colloid structure of asphalt, inhibiting the weathering reaction including asphalt condensation and asphalt oxidation. Fraass brittleness temperature and modulated differential scanning calorimetry results verified that the hybrid modified asphalt had more stable crack resistance compared with SMB at low temperature, and dynamic shear rheometer experiment proved its stable deformation resistance and excellent elasticity at high temperature during weathering. Accordingly, the addition of high content MNTR strongly improved natural weathering resistance of SMB based on the highly hybridized colloid structure.