Design and Low-Temperature Performance Evaluation of High-Modulus Co-Modified Asphalt Mixes with Rock Asphalt/Rubber Powder

High-modulus asphalt mixes are effective means to solve rutting problems, but they perform poorly at low temperatures. This study aims to enhance the modulus and low-temperature properties of mixes. Firstly, composite-modified asphalts and mixes were prepared by incorporating rubber powder and rock asphalt. Secondly, their mechanical and viscoelastic properties were investigated to determine the appropriate mass ratios of rubber powder and rock asphalt in asphalt to be 20% and 6%, respectively. The results show that both rock asphalt and rubber powder can enhance the softening point and viscosity of basic asphalt while reducing penetration. Furthermore, their combination significantly improves the high-temperature performance of the material. It is noteworthy that the rubber powder also improves the weakening of rock asphalt for mixtures at low temperatures. Finally, this study employs dynamic and static modulus tests, rutting tests, and beam bending tests to clarify the road properties of composite-modified asphalt mixes. The results indicate that mixes have high-modulus and water damage resistance while considering acceptable low-temperature performance. This paper not only enhances the adaptability of high-modulus asphalt in different environments but also expands its application range.