Storage Stability of SBS-Modified Road Asphalt: Preparation, Morphology, and Rheological Properties

The hot storage stability of styrene-butadiene-styrene triblock copolymer (SBS)-modified road asphalt can be improved significantly by reactive blending of SBS and asphalt under high share mixing at high temperature with elemental sulfur and vulcanization accelerator. The storage stability, morphology, and rheological properties were analyzed and evaluated by means of the hot storage test, fluorescent microscopy, and conventional and dynamic mechanical analysis using a dynamic share rheometer (DSR), respectively. The test results indicate that not only storage stability but also rheological properties of SBS-modified asphalt were enhanced by reactive blending of SBS and asphalt. Moreover, the addition of cross-linking agent resulted in the change in morphology of SBS-modified asphalt from a continuous asphalt phase with dispersed SBS particles to two interlocked continuous phases. The formation of a chemically cross-linked network enhanced the elasticity and deformation resistance of SBS-modified asphalt.