Investigation Of The Effect Of Sasobit/ESO Compound Warm-Mix Additive On The Performance Of SBR Modified Asphalt And Its Mixture

The severe thermal degradation of styrene-butadiene rubber(SBR)polymer during the preparation of SBR modified asphalt(SBRMA)mixture can cause a great reduction on its low-temperature performance,and the SBRMA pavement is susceptible to rutting distress in the hot summer.Nowadays,the above problems are mainly addressed by modifying SBRMA,and the common modifiers are nanomaterials and polyphosphoric acid(PPA),which play an enhancing effect on the high-temperature stability and anti-aging performance of SBRMA,respectively.However,the addition of these modifiers can impair the low-temperature cracking resistance of SBRMA to varying degrees,and the construction temperature of SBRMA pavement is not decreased,which consistently fails to effectively mitigate the degree of thermal degradation of SBR polymer during short-term aging.To resolve the above issues,the compound of Sasobit and epoxidized soybean oil(ESO)was used as a new warm-mix additive to modify SBRMA in this paper.First of all,the optimal dosage of Sasobit and ESO can be separately determined by testing the influence of different dosage modifiers on the physical performance of SBRMA.Afterwards,the effect of Sasobit/ESO on the performance of SBRMA before and after aging was investigated by physical and rheological tests,and the short-term aging thermal degradation of SBR polymer under the effect of Sasobit/ESO was observed by fluorescence microscopy,and Fourier transform infrared spectroscopy was used to test the change in the functional groups of Sasobit/ESO warm-mix SBRMA during aging and to analyze the chemical reaction occurring in the compound modification.Finally,the influence of Sasobit/ESO on the road performance and the anti-aging performance of SBRMA mixture before and after aging were evaluated in terms of high-and low-temperature stability,moisture sensitivity and fatigue cracking resistance.The major conclusions are obtained as follows:(1)The optimum dosage of Sasobit and ESO in Sasobit/ESO compound is 4 %and 6 %,respectively.Sasobit/ESO can effectively reduce the short-term aging temperature of SBRMA by 20 ℃,improve its high-and low-temperature performance,and significantly mitigate the damage of SBR network structure during the short-term aging of SBRMA.(2)The addition of Sasobit/ESO can effectively improve the thermal cracking resistance of SBRMA after both short-and long-term aging,and can improve its intermediate-and high-temperature performance grade by two levels,respectively.Physical,rheological and functional group aging indices show that Sasobit/ESO can significantly enhance the short-and long-term aging resistance of SBRMA with or without considering the warm-mix effect.(3)The three new characteristic peaks in FTIR of SBRMA after Sasobit/ESO modification are all caused by the inherent characteristic peaks of ESO,and no new characteristic peaks are generated after the mixture of Sasobit and ESO.Therefore,it can be inferred that Sasobit/ESO only has a physical modification effect on SBRMA.(4)The high-and low-temperature stability,water stability and fatigue performance of SBRMA mixture before and after aging are greatly enhanced by Sasobit/ESO,and the high-and low-temperature performance aging indices show that the resistance to short-and long-term aging of SBRMA mixture is significantly strengthened.