Asphalt mastic, which consists of an asphalt binder and a mineral filler, provides critical adhesion and viscoelasticity to an asphalt mixture. The rheological response of the asphalt mastic is mainly derived from its asphalt binder. In this study, a simple laboratory test method is proposed to estimate the relationship of asphalt binder and its mastic. Two modified binders (3.5% and 4.0% styrene–butadiene–styrene (SBS) of asphalt binder by mass) were blended with a limestone filler at six different mineral filler contents to produce mastic samples. A modified multiple stress creep-recovery (MSCR) test was conducted on both the asphalt binder and its mastic with the same testing protocols, and the stress conditions and rheological response of asphalt binder in the mastic with linear or nonlinear viscoelasticity were both investigated. The results show that the stress of the asphalt binder in its mastic decreased with increasing filler contents. However, for the linear-viscoelasticity mastic, the decrease rate of the stress began to slow down when the filler content had reached 100% or 120%. For the rheological properties of the asphalt binder in the mastic, the %R of the asphalt binder was improved by adding filler, especially for the nonlinear-viscoelasticity mastic. The asphalt binder of the linear-viscoelasticity asphalt mastic also showed a linear viscoelastic response and a good recovery property. The performance of the asphalt mastic and rheological properties of its asphalt binder were highly related to its filler content.

The performance of an asphalt mixture is significantly affected by the properties of its asphalt mortar, which consists of an asphalt binder, mineral fillers, fine aggregates and air voids. The aim of this work was to evaluate the correlations between the high-temperature performance of an asphalt mixture and the rheological properties of its corresponding asphalt mortar. The multisequence repeated loading (MSRL) test was used to estimate the high-temperature performance of the asphalt mixture. Six different gradations, AC-13, SMA-13, SUP-13, AC-20, SUP-20 and AC-25, and two styrene–butadiene–styrene (SBS)-modified asphalt binders were considered and used to prepare the asphalt mixture specimens. The gradations and asphalt types of asphalt mortars were consistent with their asphalt mixtures. A modified multiple-stress creep–recovery (MSCR) test was proposed for evaluating the rheological properties of asphalt mortar with a dynamic shear rheometer (DSR). Based on the basic form of the Hirsh model, a multiple regression model was established, and its coefficient of determination (R-square) was 0.96. The rheological response of the asphalt mortar presented great correlation with the high-temperature behaviour of the asphalt mixture. In addition, the MSCR indicators (nonrecoverable compliance and percent recovery) obtained at 12.8 kPa creep stress represented the rheological status of asphalt mortar in asphalt mixture well. Therefore, the mechanical behaviours of asphalt mixture at high temperature could be accurately predicted by the MSCR indicators of asphalt mortar and its coarse aggregate parameters.