Characteristics Evaluation and Application of SBS Composite Modified bitumen Materials in Low Temperature Environment

To improve the resistance of bitumen pavement to low temperature cracking, the study proposes a composite modified bitumen based on styrene butadiene styrene copolymer and crumb rubber. It is also tested for its performance in low temperature environment. The test results indicated that although after aging and freeze-thaw cycles, the creep rate of both modified bitumen and styrene butadiene styrene copolymer/crumb rubber were reduced. However, the creep rate of styrene butadiene styrene copolymer/crumb rubber composite modified bitumen was always better than that of styrene butadiene styrene copolymer modified bitumen. As an example, the creep rate of aged bitumen was 0.37 and 0.44 at -12°C, respectively. When bitumen mixes underwent freeze-thaw cycles and age, their fracture energy densities all drastically decreased. The fracture energy density of styrene butadiene styrene copolymer/crumb rubber composite modified bitumen mixtures, on the other hand, was larger than that of styrene butadiene styrene copolymer modified bitumen mixtures. The above results indicate that the composite modified bitumen with styrene butadiene styrene copolymer/crumb rubber has good rheological ability and freeze-thaw resistance, which can effectively ensure the low temperature performance of bitumen pavement.