Evaluation of moisture susceptibility of asphalt mixtures using dynamic modulus

A pothole is one of the distresses in asphalt pavement caused by the presence of water in the asphalt pavement and the presence of traffic passing over the affected area. Recently, lots of potholes were observed due to heavy rain in Korea. Thus, the indirect tensile strength ratio (TSR) is commonly used based on the AASHTO T 283 procedure to evaluate the moisture susceptibility of an asphalt mixture; however, TSR cannot be used as a representative index for the mechanical behavior of the moisture-conditioned asphalt mixture. In this study, the dynamic modulus /E∗/ laboratory test is applied as a replacement test for the TSR in order to assess the moisture susceptibility of four different asphalt mixtures. The dynamic modulus test is used to determine the % of retained stiffness, a term that was referred to as the dynamic modulus ratio (DMR). The results of both TSR and DMR conducted on the same mixtures are compared and statistically analyzed. The logistic regression model was used to evaluate the correlation between TSR and DMR. The correlation between TSR and DMR at 20°C is significant. However, there was no relation between TSR and DMR at other temperature ranges (5°C, 40°C, 54.4°C) because there was different viscoelastic behavior at different temperature.