Investigating the sensitivity of mineral aggregate size on the dielectric response of asphalt concrete based on a multiscale experiment

Investigation of the dielectric properties of asphalt pavement materials is critical for the application of the ground penetrating radar non-destructive testing techniques. This study focused on the effect of each part with different particle sizes in mineral aggregates on the bulk dielectric response of asphalt concrete materials. Multiscale experiments were conducted with different mineral aggregate particle mixtures (mastic, mortar, and asphalt concrete materials). By combining the multi-scale test data and micromechanical method, the sensitivity of the mineral’s aggregate size, including the size effect induced by the interface behaviors of the asphalt–mineral aggregate, was analyzed. The results indicate that (i) the dielectric response of asphalt concrete is mainly dominated by its mineral aggregates, and the particle size is one of the main factors affecting the polarization of asphalt–particle mixtures; (ii) the interface effects increase the polarization of the filler and fine aggregates in asphalt; and (iii) the cumulative effect of unit volume of the filler and fine aggregate on the overall dielectric response of the asphalt mixture, i.e., the cumulative weight, shows a natural logarithmic growth.