Dynamic modulus and viscoelastic properties of rock compound asphalt modified asphalt mixtures

Abstract The rock-compound asphalt-modified additive (RCA), synthesized from natural rock asphalt, nano-high fractions, and other components, is a novel high-modulus asphalt mixture additive. When applied to pavement surface layers, it enhances fatigue and rutting resistance. This study investigates the influence of RCA dosage on the high-temperature stability, fatigue resistance, and water stability of asphalt mixtures and identifies the optimal binder/aggregate ratio and RCA content. Results demonstrate that RCA incorporation significantly improves rutting resistance, fatigue resistance, and water stability of asphalt mixtures. The optimal mix road performance is achieved at a binder/aggregate ratio of 4.0% and an RCA dosage of 1.0%. Under high-temperature and low-frequency loading conditions, the dynamic modulus of RCA-modified high-modulus asphalt mixtures substantially exceeds that of conventional mixtures. Viscoelastic behavior depends on mix gradation and temperature: increasing coarse aggregate proportion or decreasing temperature reduces creep deformation in the asphalt mixture.