Study of temperature variations in asphalt pavement at the microscale

Abstract To investigate temperature variations within asphalt pavements during hot recycling, this study constructed a heterogeneous model of the pavement using industrial computed tomography (CT) and digital image processing. Building on heat-transfer theory, it then proposed a three-dimensional heterogeneous heat transfer model and evaluated its reliability through calculations of thermophysical parameters. The accuracy and precision of this heterogeneous heat transfer model were further verified via controlled heating experiments. In addition, the temperature field distribution characteristics of heterogeneous asphalt pavements were compared with those predicted by an idealized homogeneous heat transfer model. The results indicate that the proposed three-dimensional heterogeneous heat transfer model accurately captures the thermophysical behavior of real asphalt pavements. Relative to the homogeneous model, it shows markedly better agreement with experimental measurements, with a coefficient of determination (R 2 ) exceeding 0.95. Under steady-state heat transfer conditions, the model more precisely resolves temperature variations within aggregate structures, thereby providing more reliable thermal data. This optimized model offers a solid theoretical foundation for asphalt pavement maintenance and hot-recycling technologies.