Influence of SBS Concentration on the Properties of Short-Term Aged SBS-Modified Binders

This study demonstrates that SBS concentration plays an important role in the property evolution of SBS-modified binders (SBS-MBs) during short-term aging. At low SBS concentrations ≤3 wt.%, the stiffening of the base binder dominates the property changes, while the degradation of the SBS molecules has only a marginal effect due to RTFO aging. At low SBS concentrations (≤3 wt.%), the SBS polymer molecules are discretely dispersed in the binder matrix, due to which their influence will be marginal before and after RTFO aging. When the SBS concentration is between 3 and 5 wt.%, the degradation of the SBS molecules during RTFO aging adversely affects the interconnected SBS-rich network, resulting in a steep decline in the performance properties of SBS-MBs. At SBS concentrations ≥5 wt.%, the stiffening of the binder and the degradation of the SBS molecules may have a weaker influence on the overall properties of SBS-MBs after RTFO aging.