Investigation on the Rheological Properties and Microscopic Characteristics of Graphene and SBR Composite Modified Asphalt

Styrene-butadiene rubber (SBR) is commonly used as a modifier to enhance the low-temperature performance of asphalt. However, it is worth noting that while SBR modified asphalt exhibits good low-temperature performance, its high-temperature performance is comparatively inferior. This limitation significantly restricts the widespread use of SBR modified asphalt. As a new type of nanomaterial, graphene (GR) can change the microstructure of asphalt binder and provide asphalt with better mechanical, thermal, and adhesion properties. The main purpose of this study is to explore the influence of GR and SBR composite incorporation on the performance indexes of modified asphalt, and to study its compatibility and modification mechanism from the microscopic point of view of asphalt. The weight factor optimization system of modified asphalt was established by an analytic hierarchy process, and the optimum content of GR was determined to be 0.1% in a quantifiable way. The test results demonstrate that the inclusion of graphene substantially enhances the high-temperature rutting resistance of asphalt, reduces the temperature sensitivity of modified asphalt, and improves its storage stability. However, its effect on the low-temperature performance of asphalt is relatively minimal. Microscopic experimental results reveal the formation of a stable structure at the interface between GR and SBR in the composite modified asphalt. Furthermore, the dispersed phase exhibits improved uniformity, which positively impacts the stability of the asphalt binder.