Mesoscopic investigation into dynamic heat transfer characteristics of asphalt pavement in typical daily temperature fluctuations

Thermal distress is recognised as a predominant failure mechanism in asphalt pavements. Effective mitigation of this distress can be achieved by optimising the pavement’s thermal environmental response through an understanding of its heat transfer behaviour. In this study, the dynamic heat transfer characteristics of asphalt pavement under typical diurnal temperature variations are investigated from a mesoscopic perspective. A representative mesoscopic finite element model was developed using advanced algorithms for generating virtual aggregate particles and reconstructing the microstructure of asphalt concrete. The model was validated against experimental data and then utilised to analyse seasonal variations in the dynamic thermal response. Data indicate heat flux transitions in surface layers advance. In winter, pavement heat influx delays initiation and duration decreases. In summer, heat influx at surfaces advances initiation and duration increases.These findings suggest that Suppressing heating rates and peaks of temperatures at surfaces improves pavement performance during summer. Given parity of depth and time, heat flux within aggregates exceeds heat flux within asphalt mortar. Based on model-based mechanistic inferences, coarse aggregates act as preferential pathways for rapid heat conduction, which is an essential factor to consider when designing or optimising materials for improved thermal response.