Investigation on the Fatigue and Rutting Behavior of Asphalt Binder Containing Compound Warm Mixing Agent

A composite warm-mix additive (PNSK) was developed to improve asphalt workability by reducing viscosity while maintaining rheological performance at both high and low temperatures. The warm-mix asphalt binders (PWMA) were analyzed using an integrated approach combining conventional property tests with rheological analysis. Results showed that penetration, softening point, and ductility improved. The viscosity-reduction effect was enhanced with increasing PNSK dosage, yet the benefit plateaued beyond 11% content. Additionally, the adhesion strength between asphalt and aggregate began to decrease after 11% dosage, with 12% serving as the critical threshold for adhesion deterioration. Consequently, the optimal dosage was determined to be 11% based on comprehensive consideration of all factors. LAS results demonstrated that 11%PWMA exhibited lower strain sensitivity and superior fatigue resistance at low-to-intermediate temperatures, with fatigue life increasing by nearly an order of magnitude under low strain at 20 °C. MSCR results revealed that under low stress, 111%PWMAexhibited significantly lower non-recoverable creep compliance (Jnr) and higher percent recovery (R) than the 70#, especially in the high-temperature range (54–66 °C), demonstrating superior resistance to permanent deformation. However, 1111%PWMAxhibited temperature-strain sensitivity characteristics under high-temperature, high-strain conditions, representing an inherent characteristic of WMA technology.