Abstract Manager

Mastic is the main component of an asphalt structure that deforms when stress is applied. Substantial research has been done on the deformation and creep characteristics of asphalt mastic with varying filler proportions to develop a rheological parameter. Few research, however, has examined the combined impact of active and inert fillers. This study compares the creep recovery performance of asphalt mastics fabricated with the combination of different active and inert fillers containing different modifiers and anti-stripping agents. To understand the creep recovery characteristics of aged asphalt mastic, an experimental campaign of Multiple Stress Creep Recovery (MSCR) tests following AASHTO T 350 was performed using the Dynamic Shear Rheometer (DSR). This investigation used Gilsonite and Styrene-Butadiene-Styrene (SBS) as modifiers to modify the neat PG 58-28 binder and Zycotherm and AD-Here as liquid anti-stripping agents. For fabricating the mastics, different proportions (10%,20%,30% by the weight of base binder) of Hydrated lime (HL) and Fly ash (FA) were selected as active fillers, whereas different proportions (70%,60%,50% by the weight of base binder) of Limestone (LS), Dolomite (DM) and Basalt (BS) were selected as inert filler materials. The active and inert fillers were added in such a way that the Filler Binder (F/B) ratio remains 0.8. These materials were then mixed with modifiers and anti-stripping agents. Rolling Thin-Film Oven (RTFO) protocol was applied to simulate construction and laying time oxidative aging. The performance of these mastics was compared using non-recoverable creep compliance, stress sensitivity analysis, and percent recovery analysis. AASHTO M 332 specifications have been used to classify all the mastics based on the Jnr value at 3.2 kPa and stress sensitivity. In addition, polymer modification curve specified by the Asphalt Institute (AI) were employed to interpret the test results. Based on the analysis of experimental data, active filler HL produces better creep recovery performance compared to FA, and when combined with inert filler LS, it showed the best performance. SBS-modified mastics outperformed the Gilsonite-modified mastics. The combined effect of HL and LS modified with SBS containing Zycotherm was predominant and satisfied all the creep recovery performance requirements. However, 25% of mastics failed to pass the percent recovery criteria.