Multiscale Investigation of the Factors Governing Ice-Asphalt Interfacial Adhesion Strength: Insights from Pull-Off...

Under low-temperature and high-humidity conditions, stable ice layers readily form on asphalt pavements in cold regions, and the enhanced ice-asphalt interfacial adhesion significantly increases deicing difficulty and traffic safety risks. To clarify the factors governing ice-asphalt interfacial adhesion strength, this study combines macroscopic pull-off tests and molecular dynamics simulations to systematically investigate the effects of interfacial contact area, temperature, pull-off rate, and molecular characteristics of representative asphalt components. The pull-off results show that adhesion strength increases markedly with decreasing temperature, rising from approximately 163 kPa at -2 °C to 242 kPa at -10 °C. In contrast, the nominal adhesion strength decreases with increasing ice specimen size, suggesting that size-related interfacial heterogeneity and nonuniform stress transfer may contribute to the pull-off response. The adhesion strength also generally decreases as the pull-off rate increases. Molecular dynamics simulations show that smaller asphalt-ice interfacial models exhibit higher molecular-scale nominal adhesion responses, while temperature-dependent simulations provide short-range asphalt-ice interaction descriptors for interpreting the experimental temperature trend. The calculated short-range asphalt-ice interaction energy becomes less negative from -531.4 to -352.5 kJ mol^-1 with increasing temperature, supporting the experimentally observed strengthening of adhesion at lower temperatures. Single-molecule pull-off simulations of 12 representative asphalt molecules reveal pronounced molecular differences, with molecular-scale nominal adhesion strengths ranging from 303.7 to 734.6 MPa. Asphaltene and polar aromatic molecules generally show stronger adhesion, which is associated with larger projected contact area, flatter molecular configurations, and heteroatom-induced polar sites. The molecular polarity index shows a moderate positive association with molecular-scale nominal adhesion strength. These results establish a scale-aware mechanistic correspondence between macroscopic pull-off behavior and molecular interaction descriptors at the ice-asphalt interface, providing insights for interfacial adhesion regulation and anti-icing design of asphalt pavement materials in cold regions.