Research On Road Performance Of Different Layered Silicate Modified Asphalt Mixtures

The aging of asphalt binders is one of the important reasons for the early disease of asphalt pavement.Enhancing the aging resistance of asphalt binders can effectively improve the durability of asphalt pavement.In recent years,to improve the aging resistance of asphalt,the organic layered silicate matrials have been widely used for asphalt modification and have achieved better effects.However,due to the difference in the properties of layered silicate materials,their effects on the conventional physical properties,rheological properties and aging properties of asphalt are quite different,which limits the application in the actual engineering.moreover,as for the layered silicate modified asphalt mixture,it is often prepared by the wet premixing process,which has some drawbacks,such as the complicated process and high energy consumption.Furthermore,the current researches mainly focus on the effect of layered silicate materials on the aging resistance of asphalt binders,while few on the asphalt mixtures.Therefore,it is necessary to explore the influence of layered silicate materials types on the road performance of asphalt binder and its mixture,and that of the preparation process on the road performance of these modified asphalt mixtures,which has important theoretical and practical significance for improving the durability of asphalt pavement.In this paper,to improve the aging resistance of asphalt,firstly,the organic montmorillonite(OMMT)and organic rectorite(OREC)wereselected to modify the matrix asphalt respectively,and their effects on the physical properties,rheological properties and aging properties of asphalt are compared.Secondly,Fourier transform infrared spectroscopy(FTIR)was carried out to study the effects of OMMT and OREC on the microstructure of asphalt before and after aging,so as to explore the interaction mechanism.Lastly,the OMMT and OREC modified asphalt mixtures were prepared by dry process and wet process respectively,and then their road performance was also studied,so as to study the effect of layered silicate types and preparation processes on the road performance of asphalt mixture.By comparing the road performance of the traditional SBS modified asphalt mixture before and after aging,the road performance of the OMMT and OREC modified asphalt mixture was comprehensively evaluated.The test results show that the addition of OMMT and OREC into asphalt can significantly improve the high temperature stability,water stability and aging resistance of asphalt mixtures,while reduces the low temperature cracking resistance.This is mainly attributed to the fact that the addition of OMMT and OREC significantly improves the high-temperature performance of the asphalt,increases its viscosity and aging resistance,but it has an adverse effect on the lowtemperature performance of asphalt.in addition,the road performance of OMMT modified asphalt mixture is better than that of OREC modified asphalt mixture.And the OMMT and OREC modified asphalt mixture prepared by the dry process shows better road performance than that of wet process.Compared with the traditional SBS modifiers,OMMT and OREC,as the new types of asphalt modifiers,have the greater advantages in improving the aging resistance of asphalt binders and mixtures,especially their long-term aging resistance.