Research On Rheological And Microscopic Characteristics Of Warm-mixed Rubber Powder Modified Asphalt Under Aging Conditions

Warm-mixed rubber powder modified asphalt has been widely concerned for its good road performance and various economic benefits.Aging is a problem that warm mix rubber powder modified asphalt needs to face from production to the end of its service life.Starting from two aspects of characteristics,the performance changes of warm-mixed rubber powder modified asphalt before and after aging are analyzed,and the mechanism of the effects of SDYK surfactant incorporation and aging on asphalt performance is studied.First,the dynamic shear rheometer and curved beam creep meter were used to analyze short-term and long-term aging of rubber powder modified asphalt,and warm-mixed rubber powder modified asphalt.The results show that the high temperature rheological performance,low temperature crack resistance and aging resistance of warm-mixed rubber powder modified asphalt are better than rubber powder modified asphalt;After short-term and long-term aging,the high-temperature anti-deformation ability of asphalts is improved,and the anti-fatigue and anti-aging properties are reduced.Secondly,the qualitative and semi-quantitative analysis of the chemical functional groups of the asphalts was performed using infrared spectroscopy.The results show that:SDYK surfactant is mainly used for physical modification of rubber powder modified asphalt.As the aging degree deepens,the carbonyl,sulfoxide and aromatic ring contents of the asphalts increase,and the contents of aliphatic and branched alkanes decrease.SDYK type surfactant play an anti-aging role in the aging process.The correlation coefficient between the aromatic ring index and the improved rut factor is the highest,indicating that the aromatic ring index can more accurately reflect the rheological properties of asphalt.Finally,using the atomic force microscope,the aging behavior of asphalt is studied from two aspects: microstructure and mechanical properties.The results show that the addition of SDYK type surfactant reduces the root-mean-square roughness of the rubber powder modified asphalt,and reduces the micro-adhesion,improves DMT modulus and dissipative energy.The square root roughness decreases,the microscopic adhesion decreases,the DMT modulus and the dissipation energy increase,and the rate of change of the root mean square roughness and DMT modulus of the warm-mixed rubber powder modified asphalt is lower than that of the rubber powder modified asphalt,this shows that the anti-aging performance of warm-mixed rubber powder modified asphalt is superior;the statistical analysis software is used to analyze the correlation between themicro-characteristic index and chemical functional group index,micro-characteristic index and rheological index,showing that both of them have a good correlation.