Heat Conduction Behaviors in Semiflexible Pavements Using Discrete-Element Method

Semiflexible pavement (SFP) includes asphalt mixture skeleton, cement mortar, asphalt mortar, and residual voids. The heat conduction behaviors in the SFP become very complicated. To understand the heat conduction behaviors in the SFP, the discrete element model (DEM) of SFP was first established. Then the heat conduction behaviors, temperature field distribution, and effects of residual pores on heat conduction were investigated. Results indicate that the temperature field distribution at the same pavement depth is relatively uniform, and the heat conduction mainly happens in the vertical direction. The aggregate requires more heat to rise temperature, successively followed by asphalt mortar and cement mortar. The aggregate requires longer heat conduction time, but which does not affect the whole heat transfer. Also, when there are residual pores in the SFP, the temperature at the pore top is higher and the temperature at the pore bottom is lower than that at the same pavement depth without pores due to the thermal resistance of pores, respectively. Furthermore, the larger the pore size is, the higher the temperature difference is. Finally, when the pore is closer to pavement surface, the temperature difference between pore bottom temperature and other temperature at the same pavement depth without pores becomes higher. It is proposed that the large residual pore should be avoided or decreased to reduce the distresses of SFP.