Effect of volcanic ash filler on thermal viscoelastic property of SBS modified asphalt mastic

[Display omitted] •VA granules showed nano-porous structure and bumpy micromorphology.•VA can further improve the high- and low-temperature performance of SBS mastics.•The strength and flexibility of SBS mixes were further improved by VA fine fillers.•A filler-SBS-binder system in mastic was formed by the combination of VA and PMB. In this study, the effect of volcanic ash (VA) fine filler and SBS modifier on the thermal stability of asphalt mastics was investigated. Firstly, the micromorphology, porosity and particle properties of VAs were characterized with Scanning Electron Microscopy (SEM), N2 adsorption tests and Laser Particle Size Analyzer (LPSA), respectively. Secondly, frequency sweeping Dynamic Shear Rheometer (DSR) tests on mastics at −20 °C and 60 °C and three-point bending tests on mixes at −10 °C were conducted. The viscoelastic properties of the mastics were analyzed with the aid of linear viscoelastic (LVE) element models. It was found that the modification of asphalt by SBS was the dominant factor for improving the high- and low-temperature performance of mastics. Furthermore, VA filler can further enhance the mechanical properties of SBS modified asphalt mixture via a solid filler-SBS-binder system formed within mastics due to the complex topography and porous structure of VA.