Study on the Application of Microwave Heating in Thermal Regeneration of Asphalt Pavement

In this study, the impact of microwave heating on the stacked aggregates’ heating rate and uniformity was investigated by changing the microwave power and the type, particle size, and mass of aggregates. The impact of microwave heating on the aging performance of asphalt that was recovered from RAP materials and pavement performance of reclaimed asphalt mixture was investigated by comparing it with oven heating. The results show that the microwave heating rate increases with microwave power. The order of microwave heating rate from high to low is diorite, basalt, and limestone. The microwave heating rate usually increases with increasing particle size, except for limestone and basalt of 4.75–9.5 mm. The larger the mass, the lower the microwave heating rate, but the heating uniformity remains excellent. Compared with oven heating, microwave heating ages asphalt to a lower degree and improves the performance of reclaimed asphalt mixture in all aspects, except high-temperature stability.