An experimentally-based viscoelastic behavior of asphalt mastic at high temperatures

Mastic properties play important role in the performance of asphalt concrete, especially for high temperature performance. The objective of this paper was to describe the viscoelastic behavior of asphalt mastic at high temperatures and determine the regression constants of the models. Two different asphalt binders namely AS-70 base asphalt binder and SBS modified asphalt binder were selected to mix with the mineral filler. For each asphalt binder, asphalt mastic samples were prepared at five different mass percentages, as 0.6, 0.9, 1.2, 1.5 and 1.8. The viscosity and rheological properties were tested under different temperatures using Brookfield RVDV-III rotating viscosimeter and Dynamic Shear Rheometer (DSR). The test results indicated that, for the modified asphalt mastic, increasing mineral filler content in the mastic caused a significant increase in the viscosity, while the effects were not significant on the base asphalt mastic. The filler showed no obvious effect on the temperature sensitivity of the mastic. The creep characteristic of base asphalt mastic can be modeled by the Maxwell model. The Burgers model was the most appropriate to model the creep characteristic for the modified asphalt mastic. The relaxation function of Burgers model can successfully fit relaxation behavior of the mastic.