Dielectric properties of asphalt mastics considering temperature effect

Abstract

Ground Penetrating Radar (GPR) evaluates the quality of asphalt pavements and identifies different distresses based on the difference in the dielectric properties of asphalt pavement materials at different positions of the asphalt pavement structural layers. Asphalt mastic is an important component of asphalt mixture, and the performance of the mortar considerably affects the macro dielectric properties of the mixture. Hence, investigating the dielectric properties of asphalt mastic is crucial in understanding the overall dielectric properties of asphalt mixture. As a temperature-sensitive material, asphalt mastic exhibits temperature-dependent variations in its dielectric properties. Thus, this study conducted tests to investigate the dielectric properties of asphalt mastic at different temperatures and evaluated classical dielectric models. The results showed that the classical models did not adequately predict the dielectric properties of asphalt mastic because classical models ignore the effect of temperature on the dielectric properties of asphalt mastic. Micro test results show that temperature will affect the surface and internal structure of asphalt mastic, and then affect the performance of asphalt mixture.Through model verification, it is found that the model has a high calculation accuracy, which is more than 90%. This can quantify the influence of temperature field on the dielectric properties of asphalt mastic, and also pave the way for the next research on the temperature effect on the dielectric properties of asphalt mixture. This is because the proposed model not only considers the dielectric constant of asphalt mastic components, but also considers the influence of temperature on the dielectric constant of components. These research results not only have important academic value for enriching and developing the basic theory of GPR, but also can provide guidance for selecting the best filler-asphalt ratio in the actual field.