Rheological Behavior of Crumb Rubber/Plasticized Crumb Rubber Composite Modified Asphalts Under Different Aging Conditions

Composite modified asphalt was prepared from SK90# base asphalt, 40-mesh ordinary crumb rubber, plasticized crumb rubber, and TOR to study its rheological aging behavior. TFOT and PAV simulated short- and long-term aging, while physical tests, temperature sweep, and MSCR tests by DSR analyzed the influencing factors. Crumb rubber strengthens asphalt hardness and high-temperature deformation resistance. Plasticization improves rubber–asphalt compatibility and reduces viscosity, complex modulus, and rutting factor. Under the tested aging conditions, the plasticized crumb rubber-modified asphalt shows higher aging sensitivity in high-temperature rheological and MSCR indicators. Rising stress lowers the recovery rate and elevates non-recoverable creep compliance. TOR optimizes aged rheology, and composite modified asphalt outperforms single rubber-modified asphalt after long-term aging.