Analysis Of Rheological Properties For Composite Modified Asphalt Based On PG And Infrared Spectroscopy

In order to improve the properties of modified asphalt comprehensively,the research of composite modified asphalt has been put forward and good results have been obtained.Compared with a single modifier,two or more modifiers are added to the composite modified asphalt,including SBS,SBR,TPS and Rubber Powder,etc.By using the characteristics of different modifiers,the properties of composite modified asphalt are improved simultaneously.In this study,the macro rheological properties(high temperature stability and low temperature stability)of composite modified asphalt were measured based on the optimal dosage(4%SBS+3%SBR,4%SBS+15%rubber powder and 4%SBR+15%rubber powder).The changes of the stability indexes(complex shear modulus G*,phase Angle&and rut factor G*/sinδ)at high temperature and the creep stiffness modulus S and creep rate m at low temperature were analyzed.At the same time,infrared spectroscopy was used to investigate the characteristics of microcosmic functional groups and the changes of characteristic functional groups(carbonyl functional groups and aromatic ring functional groups)in the anti-aging process of composite modified asphalt.Furthermore,the micro-functional group index was used to characterize the performance difference of composite modified asphalt,and the relationship between macro-high and low temperature index(rut factor and Burgers model parameters)and micro-functional group index(carbonyl group and aromatic ring)was studied by means of data fitting and grey correlation analysis.The relationship between macro rheological properties and micro chemical functional group index of composite modified asphalt was established.The results show that 4% SBS+15% rubber powder modified asphalt has the advantage of high and low temperature stability.Its deformation resistance and aging resistance is also relatively better.The fitting parameters of high-temperature rutting factor G*/sinδ and lowtemperature Burgers model are more reasonable to characterize the performance of composite modified asphalt.In addition,IR spectrum test shows that the modification effect of composite modifier and asphalt is mainly realized through physical combination.Carbonyl,sulfoxide and aromatic ring contents increased with aging time,while aliphatic contents decreased with aging.When analyzing the anti-aging properties of asphalt by infrared spectroscopy,the peak area of 4000cm-1-700cm-1 has high accuracy and identification,and can be used as the benchmark standard for analyzing the microchemical functional group index of composite modified asphalt.