Laboratory evaluation of warm-mix epoxy SBS modified asphalt binders containing Sasobit

Abstract As most popular thermoplastic and thermosetting polymers, styrene-butadiene-styrene triblock copolymer (SBS) and epoxy resin have been extensively applied in polymer modified bitumen. In this paper, epoxy SBS-modified asphalt (ESBA) containing high percentage of industrial SBS modified asphalt (SBA) was prepared. To lower the viscosity, an organic warm mix asphalt (WMA) additive, named Sasobit, was incorporated into SBA to prepare Sasobit modified ESBAs. The effect of Sasobit concentration on the morphology and performance of the neat ESBA was investigated. By adding Sasobit, the viscosity of the neat ESBA decreased and the construction time of the ESBA mixture was extending. Regarding the newly formed microstructural morphology, curly ribbon crystalline structures formed in Sasobit modified SBA. However, no crystalline structures were observed in the secondary SBA phase of Sasobit modified ESBAs. Sasobit disrupted the spherical phase-separated morphology of the neat ESBA. In terms of the Sasobit modified ESBAs, the co-continuous phase-separated morphology converted to phase-inverted morphology with the increase of the WMA additive concentration. Sasobit improved the low-temperature performance of the neat ESBA. The WMA additive weakened the damping properties of the neat ESBA. However, the low-temperature toughness and high-temperature stability of the neat ESBA were improved with the existence of Sasobit. The inclusion of 1.2 Sasobit enhanced the elongation at break and toughness of the neat ESBA. Furthermore, Sasobit increased the Young's modulus of the neat ESBA.