Effect of mineral filler on properties of warm asphalt mastic containing Sasobit

The dynamic shear rheometer (DSR) and bending beam rheometer (BBR) were used to characterize the high-temperature properties and low-temperature properties of different Sasobit warm asphalt-mineral filler mastics. The Limestone fillers (LM), Portland cement (PC), and Hydrated lime (HL) were selected as mineral fillers. Eight fill-to-binder (F/A) ratios for each type of mineral fillers were considered in this study: 0 (without filler), 0.3, 0.6, 0.9, 1.2, 1.5, 1.8 and 2.1 by the weight of asphalt binder. The effects of F/A ratio on the complex shear modulus (G*), phase angle (δ), G*/sin δ and creep stiffness (S) of various kinds of warm asphalt-mastics were studied. Results of the study showed that the filler type and the F/A ratio had significant effects on the complex shear modulus (G*) and G*/sin δ, but had slight effects on the phase angle (δ). The F/A ratio had significant effects on the creep stiffness S, while the filler type had insignificant effects on it. It was also shown that the best function that described the relationship between each of G*, G*/sin δ and S and the F/A ratio was the exponential function. Based on the rate of rheological curve, the optimum range of F/A ratios were obtained to balance the high-temperature and low-temperature properties.