Dielectric Model Considering Interface Effects for Asphalt Mixtures Based on Spherical Polarization Theory

Accurate measurement and calculation of the dielectric constant of asphalt mixture serve as fundamental steps for enhancing the precision of ground-penetrating radar (GPR) in asphalt pavement quality inspection. To establish a dielectric model that precisely captures the structural characteristics of asphalt mixtures, mesostructure and microstructure analyses of the asphalt mixture are conducted based on a multiscale analysis approach; the results are then correlated with the macroscopic dielectric properties of the materials. Leveraging principles from dielectric physics, particularly the spherical polarization theory, a dielectric model for the mesostructure of the hybrid medium is developed (referred to as the improved model). Building upon the improved model, an asphalt mixture dielectric model that considers the microscale interface effect is constructed using the composite sphere combination method (referred to as the presented model). The results demonstrate that the improved model enhances the precision of calculating the dielectric constant of asphalt mastic and mixture by an average of 1.53% and 2.94%, respectively, compared to the original classical model. Moreover, the presented model shows further enhancement in accuracy compared to the improved model. Specifically, the overall average improvement of the presented model over the improved and original classical models is 2.86% and 5.8%, respectively. Notably, the presented model exhibits significantly higher accuracy compared to other classical models (such as the S-K, Looyenga, and Brown models). The research models align more closely with the actual composition of asphalt mixture, resulting in more precise calculation of the dielectric constant. This study offers guidance for enhancing the accuracy of GPR road quality detection and for the application of dielectric properties in the field of intelligent transportation.