Viscoelastic and Damping Behavior of Composed Modified Asphalt for Functional Interlayers in Photovoltaic Pavements

This study presents the development and performance evaluation of a rock asphalt-modified damping asphalt binder tailored for interlayer applications in photovoltaic pavement systems. A series of composite binders was formulated by incorporating Qingchuan rock asphalt, crumb rubber powder, and SBS polymer into base asphalt using an orthogonal design approach. The effects of different modifiers and their interactions were systematically assessed through conventional physical tests, DSR, BBR and damping ratio measurements. Furthermore, full-scale specimens (30 cm × 30 cm) were subjected to both single-pass and 24 h sustained loading tests to simulate real-world stress conditions. The results revealed that rock asphalt (RA) significantly enhanced the high-temperature stiffness and rutting resistance, while SBS improved ductility and low-temperature flexibility. Rubber powder (RP) notably increased the damping ratio, demonstrating superior energy dissipation potential. Among the nine formulations, the ternary blend of SBS, RA, and RP (denoted as L5) exhibited the most balanced and optimal performance, with G*/sinδ exceeding 5.0 kPa at 64 °C, a ductility of 132 cm, and damping ratios above 0.14. Load testing confirmed the material’s capacity for both instantaneous deformation resistance and delayed elastic recovery. These findings suggest that the L5 formulation is well suited for use in smart pavements where both mechanical durability and vibration attenuation are required.