Study On High And Low Temperature And Self-healing Properties Of Nano-TiO₂/OMMT/SBS Modified Asphalt

Due to the increasing traffic volume,the original asphalt materials no longer meet the road requirements of modern traffic,therefore,the use of modified asphalt for road construction has become a trend.Nano-modified asphalt is a common technology in the field of road materials,among which,nano-Ti O₂material is widely concerned because it can significantly improve the high temperature performance of asphalt when modified with SBS compound,however,there are problems of poor dispersion and serious segregation of nano-Ti O₂and SBS in the modification process,so this paper selects organic montmorillonite（OMMT）and nano-Ti O₂as asphalt modifier to Therefore,this paper selects organic montmorillonite and nano-Ti O₂as asphalt modifier to modify SBS modified asphalt,which is of great practical significance to the development of modified asphalt.Firstly,nano-Ti O₂/SBS modified asphalt,OMMT/SBS modified asphalt and nano-Ti O₂/OMMT/SBS modified asphalt with different contents were prepared,and their basic physical properties were analyzed by three major indexes,Brinell’s viscosity and degree of segregation,and the results showed that nano-Ti O₂and OMMT lowered the needle penetration of modified asphalt,increased the softening point and viscosity,and slightly increased the ductility with proper content.The ductility was slightly increased under the appropriate content.Secondly,the high and low temperature rheological properties of the modified asphalt with different content levels of nano-Ti O₂/OMMT/SBS were analyzed by dynamic shear test and bending beam rheological test,and the results showed that the high temperature deformation resistance of the composite modified asphalt was better than that of SBS modified asphalt at different temperatures,frequencies and strain levels,and it showed good low temperature performance with appropriate content,and the best combination is0.5%nano-Ti O₂and 4%OMMT.Third,the basic physical indexes and rheological properties after aging show that both nano-Ti O₂and OMMT effectively improve the aging resistance of asphalt,and the lowest performance loss of asphalt after aging when the two only act synergistically.Fourth,the fatigue resistance of asphalt can be improved with the increase of nano-Ti O₂and OMMT content through fatigue factors and load times;healing test analysis shows that the healing index of SBS asphalt after adding nano-Ti O₂and OMMT modifiers are higher than that of SBS asphalt,and is basically positively correlated with the total amount of modifier content,asphalt healing index increases with the healing temperature and healing time.The self-healing ability of the composite modified asphalt pavement is stronger.Finally,the microscopic analysis of modified asphalt,scanning electron microscope images show that the dispersion of nano-Ti O₂and OMMT compound blended into asphalt is high,and can be fully dispersed in SBS modified asphalt;infrared spectroscopy shows that the modification process of nano-Ti O₂and OMMT on asphalt is physical modification,and the compound modification effect of both is physical superposition process,and the gel chromatography test confirms the modifier’s effect on the improvement of combined performance with asphalt.