Study of the Rheological Properties of Rubberized Asphalt Mortar: Mechanisms of Action of Rubber Powder and Filler–Binder Ratio

Rubber asphalt mortar is widely utilized in road engineering for its excellent high-temperature stability and low-temperature crack resistance, but the influence mechanisms of the rubber powder’s mesh size, content, and filler-to-binder ratio on its performance remain unclear. This study systematically evaluated these factors through viscosity testing, rheological experiments, and viscoelastic analysis. The results indicate that the rubber powder content and filler-to-binder ratio significantly affected the viscosity and rheological properties of the mortar, with the 40-mesh rubber powder demonstrating optimal stability. The grey correlation analysis revealed that the filler-to-binder ratio is the most critical factor, followed by the rubber powder content and mesh size. The findings suggest that optimizing the filler-to-binder ratio and rubber powder content, along with appropriate temperature control during construction, can significantly enhance the mortar’s performance, providing a scientific basis for road engineering applications.