Study on the phase behavior of asphalt mastic

Abstract

In order to improve the road performance of asphalt mixture, the phase behavior of asphalt mastic which is the most important component of asphalt mixture was studied. The glass transition temperature (Tg) and glass transition activation energy of asphalt mastic were obtained by the dynamic mechanics analysis (DMA) method, and the effect of fillers on the distribution of wax in asphalt was studied by the differential scanning calorimetry (DSC). The effect of fillers on temperature sensitivity of asphalt mastic was studied through Brookfield viscometer. The phase separation of asphalt mastic and the applicability of time temperature superposition principle (TTSP) on asphalt mastic were studied by van Gurp-Palmen (vGP) plot. The results show that the faster the load frequency is, the higher Tg is, and the addition of fillers can increase Tg and glass transition activation energy. The distribution of wax in asphalt is discrete, and fillers have little impact on it. The addition of fillers can improve the temperature sensitivity of asphalt mastic, and the effect order is as follows: granite>andesite>limestone. The TTSP is effective for virgin asphalt at any temperature because of its homogeneity, but it is not effective for modified asphalt when the temperature is higher than 45°C because of its phase separation, and the addition of fillers can promote phase separation occur in modified asphalt.