Alternative to MSCR Test: A Novel Rheological Method for Evaluating Asphalt Mastic Performance at High Temperatures

The high-temperature performance of asphalt mastic is a critical factor influencing the resistance of asphalt mixtures to permanent deformation. Despite the importance of this material phase, no standardized test exists for evaluating asphalt mastic behaviour at high temperatures. Therefore, researchers often use the Multiple Stress Creep Recovery Test (MSCRT), originally designed for asphalt binder, although its applicability to asphalt mastic is limited. This study proposes a novel rheological method referred to as Single Shear Creep Test (SSCT) as a more robust alternative for assessing the performance of asphalt mastic at high temperatures. The SSCT applies a constant shear stress over an extended period, allowing for the determination of the steady-state creep rate as a rheological performance indicator. A comprehensive experimental program involving 45 asphalt mastic variants, produced by using 11 asphalt binder types, 15 mineral fillers, and different filler-to-asphalt binder ratios. Each variant was tested using both MSCRT and SSCT in a Dynamic Shear Rheometer (DSR). The results demonstrated that SSCT provides more consistent and rheological meaningful differentiation between materials. The results show that asphalt binder type and the filler-to-bitumen (f/b) ratio strongly influence asphalt mastic behaviour at high temperature. Filler type has a limited influence, except for hydrated lime.