Multi-physical field study of asphalt mixtures containing moisture based on microwave heating

This study aimed to understand the microwave thermal regeneration mechanism of asphalt pavement and improve its regeneration quality. Asphalt mixtures containing moisture were regarded as a porous medium to study the multi-physical distribution law of asphalt mixtures in the microwave heating process. Mass and heat transfer models of moisture and a heat transfer model of asphalt mixtures were established. The variations in moisture in the asphalt mixtures were analyzed. The asphalt mixture with a high initial moisture content presented a fast migration rate of moisture. When asphalt mixtures with different initial moisture contents were dried to a certain extent, the moisture difference was reduced, along with the differences in moisture migration rates. The temperature variations of the asphalt mixtures were studied. The asphalt mixture with a lower initial moisture content presented a higher temperature rise than the other mixtures did after heating for the same duration. As the moisture of the asphalt mixtures decreased, the differences in the overall temperatures of the asphalt mixtures with different initial moisture contents showed a decreasing trend.