Using nanometer absorbent to enhance microwave-induced blending degree of virgin and aged asphalt

In the production of asphalt mixtures containing reclaimed asphalt pavement (RAP), the traditional heating method has certain limitations, such as partial mobilization, low blending, and secondary aging. These drawbacks result in reduced technical properties of recycled asphalt mixtures, such as the crack resistance, fatigue resistance, and water stability, thereby leading to strict restrictions of RAP content in the recycled asphalt mixtures. To address these issues, microwave induction was used in this study to produce recycled asphalt mixtures. Fluorescence microscopy and molecular dynamics simulation with thermoelectric coupling field were used to examine the viability of increasing the blending efficiency by adding nanometer microwave absorbents. The findings show that microwave induction can be used to increase the blending efficiency of aged and virgin binders and that adding nanoscale microwave absorbents can further increase this efficiency. By incorporating nanoscale SiC at a concentration of 0.5%, the temperature-rising rate of asphalt under microwave heating was improved by up to 31.4%. The self-diffusion coefficient of asphalt incorporating microwave absorbent is dramatically raised and is 2.1 times that of virgin asphalt without microwave absorbent and 4.9 times that of aged asphalt, indicating that microwave absorbent is conducive to the blending of virgin and aged asphalt under microwave action.