Research on high- and low-temperature properties of asphalt-mineral filler mastic

In the asphalt mixtures, although asphalt is predominantly considered the binder holding the aggregates together, the actual product used to connect aggregate particles is the asphalt-mineral filler mastic which consists of the asphalt and mineral filler. The characterization of asphalt-mineral filler mastic is essential to improve the understanding of the response and performance of asphalt concrete pavements. It is also important to understand the high- and low-temperature properties of asphalt-mineral filler mastic. In this paper, the parameters of the viscous component of the repeat creep stiffness G_v were evaluated using a dynamic shear rheometer; and the creep stiffness modulus S was determined using a bending beam rheometer. The effects of filler/asphalt ratios F/A (on a weight basis) on the high-temperature and low-temperature properties of different asphalt-mineral filler mastics were studied. The results showed that the rheological behavior of asphalt-mineral filler mastics are nonlinear, and follow an exponent function model. The curve can be separated into three components: the slowly changing phase, the transitional changing phase, and the fast changing phase. To more easily understand the two straight line models, we calculated the F/A of the inflection point in the curve and determined that the optimal range of F/A is 0.9-1.4 to balance the high-temperature and low-temperature properties from the aspect of interacting models of asphalts and mineral fillers. Furthermore, the approach to get the optimal F/A ratio was discussed.