In cold and arid regions, the durability of asphalt pavement materials is often inadequate, and the hot mixing process further accelerates pavement ageing and releases harmful gases. To address the high-viscosity of pavement materials in such regions, lower mixing temperatures, extend the construction duration, and enhance pavement durability, this study systematically investigates a warm-mix technology for rubber-composite-modified asphalt. First, the influence of processing conditions on the viscosity-reducing effect was examined, and the optimal warm-mix preparation process was determined. Second, the properties of warm-mix rubber-modified asphalt were optimised through high- and low-temperature rheological testing. Finally, the mechanism of warm-mix modification was elucidated using microscopic techniques such as scanning electron microscopy, fluorescence microscopy and infrared spectroscopy. The results show that the 40-mesh pelletised desulphurised rubber treated with activator at a 5:1 ratio of activator at 220 °C for 50 h exhibits the optimal viscosity reduction effect. As the proportion of cracked rubber increases, the viscosity-reducing effect first intensifies and then diminishes optimal results are achieved at a dosage of 5%; the optimal comprehensive performance is achieved at a 5% proportion, where the asphalt simultaneously exhibits excellent high-temperature stability and low-temperature crack resistance. The cracking process effectively disrupts the cross-linked network structure of rubber, significantly reducing viscosity while enhancing the compatibility and stability of the asphalt system. Notably, the proposed warm-mix process reduces the production temperature of rubber-modified asphalt by 40–60 °C and lowers its viscosity by approximately 30% compared to conventional asphalt. This improvement provides crucial support for low-temperature construction and viscosity control of rubber-modified asphalt in cold and arid regions.
Wei et al. (Fri,) studied this question.