Computational analysis of mechanical responses in asphalt pavements using three-dimensional multiscale thermo-mechanical modelling

Conventional design methods for asphalt pavements remain dependable yet labour-intensive, costly and assume the asphalt behaves as a homogeneous material and oversimplify its multiscale behaviour. This study develops a three-dimensional (3D) multiscale finite element model that bidirectionally couples a meso-level asphalt structure with macro-level pavement behaviour, enabling the analysis of mechanical responses under simultaneous thermal and tire loads. The mesoscale domain was reconstructed from high-resolution X-ray computed tomography scans processed with digital image algorithms, providing a detailed representation of asphalt's heterogeneous structure. Representative climate data from North Rhine-Westphalia, Germany, were incorporated into the simulations. The results show that thermal stresses arising from temperature variations interact with longitudinal stresses caused by axial tire loads, significantly influencing stress distribution at both scales. By integrating material properties, multiscale pavement structures, tire loads and environmental conditions, this method offers a robust tool for improving asphalt pavement analysis and design, yielding more accurate performance predictions under real-world conditions.