Asphalt mixture demonstrates extensive application in pavement engineering systems spanning highway infrastructures and airport runways. Particularly in cold regions, the freeze–thaw cycles pose significant challenges to durability of asphalt mixture demanding critical attention. Current research frameworks exhibit notable limitations in comprehensively characterizing freeze–thaw damage evolution with multiscale numerical simulations integrating micromechanical analysis. To elucidate the freeze–thaw damage mechanisms of asphalt mixtures in cold region, this study established a macro-mesoscopic analysis model based on coupled theory of water–ice particle phase transition and expansion and the discrete-element method. Mesoscopic parameters were calibrated with laboratory experimental data to verify the numerical model. The synergistic deterioration effects of freeze–thaw cycles, temperature ranges, and freeze–thaw rates on mechanical properties of the asphalt mixtures were systematically investigated. The results revealed that damage accumulation accelerated significantly with increasing freeze–thaw cycles, showing a 26.3% reduction in ultimate compressive strength and a 25.7% reduction in compression modulus after 15 cycles compared with the undamaged state (0 cycles). The temperature change range governed damage pathways that the low-temperature (−30°C to 10°C) freeze–thaw cycle primarily caused aggregate skeleton failure with greater ice crystal compression, the mid-temperature (−20°C to 20°C) freeze–thaw cycle exhibited the most severe performance degradation due to the interfacial debonding, and the high-temperature (−10°C to 30°C) freeze–thaw cycle showed dynamic competition between aging and self-healing. The freeze–thaw rates regulated damage propagation modes, where slow freezing triggered progressive interfacial debonding via water infiltration, whereas rapid freezing induced sudden, localized damage through concentrated ice compression.
Luo et al. (Fri,) studied this question.