| The performance of asphalt has an extremely important effect on the performance of the mixture.By adding suitable modifiers to the asphalt,it can help the improvement of the high and low temperature performance and anti-aging performance of the asphalt and the mixture.High altitude area has unique climate,long winter time,low temperature,strong ultraviolet,large temperature difference and severe freeze-thaw cycle.The pavement is prone to low-temperature cracking and other diseases.Because of its unique climate,special areas have higher requirements for road materials,and need high-performance asphalt and asphalt mixture to pave the road.Therefore,the purpose of this paper is to prepare a kind of high-performance composite modified asphalt to adapt to the unique climate of high-altitude areas,so as to prolong the service life of the road.In this paper,the surface of the nano-ZnO was first organically treated,and the infrared spectroscopy and TEM tests were performed on the nano-ZnO before and after modification.The results showed that the agglomeration of the nano-ZnO after surface modification was greatly reduced;The basic performance indexes of the nano-ZnO modified asphalt before and after the surface modification of the nano-ZnO were verified.The test results showed that the penetration,softening point and ductility were improved to a certain extent,which proved that the modified nano-ZnO was more dispersed in the asphalt Uniform;The best content of three modifiers was obtained by orthogonal test,and nano-ZnO / SBS / SBR composite modified asphalt with better performance was successfully prepared.Zhonghai 90 # matrix asphalt,SBR modified asphalt,SBS modified asphalt and nano-ZnO / SBS / SBR composite modified asphalt were respectively tested by rotary film heating and ultraviolet aging,and the softening point difference and 5 ℃ ductility retention rate were used as evaluation indexes to compare High and low temperature properties of four kinds of asphalt before and after aging;The dynamic shear rheological test(DSR)and low-temperature bending rheological test(BBR)were performed on the four types of asphalt before and after aging,respectively,and the evaluation indicators were: rutting resistance factor G~*/sinδ,bending creep stiffness mode The amount S,creep rate m,comparative analysis of the rheological properties of four kinds of asphalt;Four types of asphalt mixture specimens were prepared and subjected to long-term thermal aging test.The four types of asphalt mixture specimens before and after aging were subjected to water immersion Marshall test,rutting test,low temperature bending test and freeze-thaw split test to ensure dynamic stability.,Residual stability in water immersion,freeze-thaw split strength ratio,bending tensile strength and failure bending tensile strain are the evaluation indicators,and comparatively analyze the difference between high and low temperature and water stability of the four types of asphalt mixture before and after aging.The test results show that the comprehensive performance of the nano-ZnO / SBS /SBR composite modified asphalt prepared in this paper is relatively good,the softening point can reach 76.8 ℃,and the ductility at 5 ℃ can reach 60.2cm.Compared with SBR and SBS modified asphalt,the performance of composite modified asphalt is the best in both high and low temperature before aging;After hot oxygen aging,the composite modified asphalt and SBS modified asphalt have almost the same high and low temperature performance;After ultraviolet aging,the performance of the composite modified asphalt is best demonstrated,and its high and low temperature properties are the best. |
