Dielectric Model of Asphalt Mastics Considering Temperature Influence

As an important stage in the three-stage dispersion system of asphalt mixtures, the structure and properties of asphalt mastics have a significant impact on the road performance and dielectric properties of asphalt mixtures. With changes in atmospheric temperature, the polarization process of the asphalt mixture is affected, and the dielectric constant changes. In this study, the dielectric properties of asphalt mastics and their single-phase media at different temperatures were studied, and the changes in the dielectric properties were analyzed using infrared spectroscopy, scanning electron microscopy, and a synchronous thermal analyzer. Finally, a dielectric model of the asphalt mastics considering the temperature effect was established. The results show that the dielectric constant of asphalt mastics increases with an increase in the filler-bitumen ratio, and the dielectric constant of bitumen, block, limestone filler, and asphalt mastics increases linearly with an increase in temperature. The combination of bitumen and filler does not produce new functional groups and chemicals, and the dielectric constant gradually increases during the transition from the glassy state to the viscous flow state. A dielectric model of asphalt mastics that considers the temperature effect was established by introducing the temperature influence factor. Compared with the classical dielectric model, the proposed model shows higher accuracy. Compared to the test results, the relative error was less than 5%. This study provides a basis for the study of dielectric models of asphalt mixtures in complex climates and further improves the accuracy of ground penetrating radar in the nondestructive testing of asphalt pavement.