Dynamic response analysis of semi-rigid asphalt pavement under combined low-temperature and heavy-load conditions.

In cold regions, asphalt pavements undergo severe deterioration driven by the synergistic effects of thermal contraction and dynamic heavy loading, resulting in premature failures such as thermal cracking and rutting. This study presents a comprehensive thermo-mechanical coupling analysis to address this critical issue. A sophisticated seven-degree-of-freedom (7-DOF) vehicle model was developed to simulate realistic dynamic loads, with load magnitudes quantified via MATLAB simulations. A three-dimensional (3D) finite element (FE) model was established, incorporating temperature-dependent material properties and transient heat transfer analysis to replicate a typical winter cooling event in Jilin Province, China. The results quantified key responses: a maximum surface thermal stress of 8.01 MPa, a vertical compressive stress of 0.86 MPa beneath the wheel load, and a detrimental tensile strain of 90.16 με at the asphalt layer base. Shear stress concentrations of up to 0.16 MPa were observed, accelerating shear-induced damage. A critical finding was the stress reversal (compression to tension) at the bottom of asphalt layers under moving load, a phenomenon crucial for fatigue assessment but often overlooked in static analysis. The study conclusively shows that low temperatures exacerbate stress accumulation and fatigue damage under heavy traffic, providing critical insights for designing durable pavement structures in cold regions.