Using Lightweight Materials to Enhance Thermal Resistance of Asphalt Mixture for Cooling Asphalt Pavement

Abstract

This study aims to enhance the thermal resistance of asphalt mixture to cool asphalt pavement. Four kinds of asphalt mixtures were prepared by replacing basalt aggregate and limestone mineral powder with shale ceramsite (SC) and fly ash cenosphere (FAC), respectively. A series of experiments, including environment scanning electron microscope test, thermophysical parameter test, indoor irradiation test, shear strength test, and rutting test, were performed to verify the purpose of this study. The results show that using low-density SC and FAC could produce lightweight asphalt mixtures, which had lower thermal conductivity than control asphalt mixture. The indoor irradiation test shows that the resultant asphalt mixtures had lower temperatures at the depth of lower than 4 cm. The addition of SC had a negative effect on the shear strength and dynamic stability of asphalt mixture. However, the two indicators increased due to the addition of FAC. The results presented in this study indicate that it is feasible to use lightweight aggregate to prepare low-thermal-conductivity asphalt mixture and use this kind of asphalt mixture to cool asphalt pavement.