Rheological properties of eco-friendly high-modulus asphalt considering aging characteristics

This study investigates the development and characterization of Eco-friendly High-modulus Asphalt (EHA) designed to optimize technical performance, environmental sustainability, and economic viability. By incorporating PR high-modulus modifiers alongside crumb rubber (CR) and desulfurized crumb rubber (DCR) into 70# base asphalt, the EHA variants were developed and benchmarked against SBS-modified asphalt (SBSMA) and traditional high-modulus asphalt (HMA). Rheological evaluations via Dynamic Shear Rheometer (DSR) reveal that the EHA series exhibits superior high-temperature deformation resistance; specifically, EHA-1 maintains a rutting factor at 76℃ that is more than three times that of SBSMA, while EHA-2 demonstrates enhanced elastic recovery following long-term Pressure Aging Vessel (PAV) conditioning due to the oxidative sensitivity of DCR. Furthermore, Bending Beam Rheometer (BBR) results indicate that the inclusion of rubber powder effectively mitigates the inherent brittleness associated with high-modulus additives, ensuring adequate stress relaxation and low-temperature crack resistance even after aging. Microscopic analyses, including SEM, FM, and FTIR, confirm that the modifiers achieve a homogeneous dispersion and form a robust physical synergistic network without fundamentally altering the asphalt's chemical structure. Finally, a material cost comparison confirms that EHA-1 and EHA-2 achieve cost reductions of approximately 4.5% and 3.6% versus SBSMA, and about 24% compared with conventional HMA, ensuring an excellent performance–cost balance. In conclusion, the EHA approach successfully overcomes the trade-off between high performance and high cost, offering a sustainable and competitive solution for high-performance pavement engineering.