Effect of novel warm-mix compound on road performance and aging resistance of SBR-modified bituminous mixture.

Through the viscosity-reducing and modification effects of warm-mix additives, the severe short-term thermal degradation of styrene-butadiene rubber (SBR) polymer in road construction can be mitigated, while compensating for the lack of SBR modified bitumen (SBRMB) pavement in high-temperature performance. This study investigated the road performance of SBRMB mixture warm-mixed by a novel compound consisting of Sasobit and epoxidized soybean oil (ESO) using Hamburg wheel-tracking, Marshall stability, −10 °C indirect tensile strength (ITS), freeze-thaw ITS, and indirect tensile fatigue tests. Aging susceptibility for bituminous mixtures was assessed through in-service performance, rheological property, and chemical structure aging indexes. Additionally, changes in the SBR network structure during thermal oxidative aging were observed by a fluorescence microscope. The results show that the Sasobit/ESO compound can effectively improve the resistances of SBRMB mixture to high-temperature rutting and thermal cracking owing to the complementary characteristics of its components. The moisture susceptibility of the SBRMB mixture is increased by Sasobit, whereas the Sasobit/ESO composite still provides a pronounced enhancement effect on moisture stability under the compensating action of ESO as well as the aging reaction. Compared with Sasobit, Sasobit/ESO composite is less effective in increasing the fatigue life of SBRMB mixture due to the undesirable effect of ESO, but the long-term aging action significantly reduces this discrepancy. Sasobit can compensate for the adverse influence of ESO on aging susceptibility, and consequently the short- and long-term aging resistances of SBRMB mixture are strengthened by Sasobit/ESO compound. Since Sasobit plays a decisive role, Sasobit/ESO compound is effective in mitigating the thermal degradation of SBR polymer in bituminous mixtures. • Sasobit/ESO enhances the comprehensive road performance of SBRMB mixture. • Sasobit/ESO improves the short- and long-term aging resistances of SBRMB mixture. • The degradation degree of SBR polymer can be effectively mitigated by Sasobit/ESO. [ABSTRACT FROM AUTHOR]