Dynamic Properties to Evaluate Moisture Sensitivity of Asphalt Mixtures

An experimental measurement of dynamic properties, including dynamic modulus and phase angle, of asphalt mixtures with varying saturation levels of moisture has been carried out in the study. The specimens of asphalt mixture were compacted with three different air void contents and two different levels of moisture saturation. The relaxation modulus expressed by Prony series was estimated from the Prony series expression of dynamic modulus. The purpose of this study is to identify the effect of air voids on dynamic properties that affect and control moisture susceptibility of asphalt mixtures and then compare the stress relaxation behavior of asphalt mixtures between dry and moisture conditioning. The results show that dynamic properties are quite sensitive to temperature and loading frequency in dry and different saturation levels of moisture. Moreover, and the smaller the air voids and saturation level, the greater the increase in dynamic modulus and rate of stress relaxation, indicating better resistance to cracking and less moisture susceptibility.