Study On The Effect Of Nano ZnO With Different Morphology On The Properties Of Asphalt And Asphalt Mixture

The western region has extreme climate characteristics such as strong ultraviolet radiation and long sunshine time,and its molecular bond energy of asphalt is similar to wavelength radiation energy.However,long-term aging will destroy the bond energy of asphalt,resulting in the internal structure of asphalt changing from colloid to solid,accelerating the formation of asphalt diseases,thus deteriorating the service life of asphalt pavement.Therefore,effective control of ultraviolet aging and performance deterioration of asphalt pavement is of key significance for long-life development of asphalt pavement.Existing studies have added nano ZnO to asphalt for performance analysis,and found that it can better improve the anti-aging performance of asphalt,but nano ZnO has some problems,such as low ultraviolet absorption capacity and poor visible light absorption capacity.Based on this,a kind of ZnO nanorods with strong UV absorption and response to visible light were prepared by low-temperature pyrolysis.Firstly,through the UV absorption test,the results show that the prepared ZnO nanorods can improve the UV absorption effect by about 10.36%and the visible light absorption effect by about 37.51%compared with ordinary ZnO nanomaterials.In addition,through thermogravimetric test,it is found that ZnO nanorods have good high-temperature stability.At 150 ℃,the weight loss is only 0.4%,which fully meets the requirements of pavement materials.Secondly,the influence of different morphologies of nano ZnO on the performance of asphalt was studied.It was found that the physical and rheological properties of asphalt were greatly improved by two different morphologies of nano ZnO,among which the rod performance was better.In different performance experiments,the difference was about 8%～10%.In the thermal oxygen aging,the performance improvement effect of the two is similar,in which the difference is about 6%～8%in the short-term thermal oxygen aging and about 3%～4%in the long-term thermal oxygen aging.However,in the part of ultraviolet aging and outdoor exposure aging,the effect of ZnO nanorods on improving the anti-aging performance of asphalt is significantly higher than that of ordinary ZnO nanoparticles,with a gap of about 10%～13%.The reason is that the ultraviolet and visible light absorption effect of ZnO nanorods modified asphalt is better than that of ordinary ZnO nanoparticles modified asphalt.Finally,it was applied to asphalt mixture to study the effect of nano ZnO with different morphology on the pavement performance of asphalt mixture.It is found that the modified asphalt mixture is better than the matrix asphalt mixture in high temperature,low temperature and water stability,which is basically consistent with the change of physical properties of modified asphalt.In terms of high-temperature performance,there is a big gap between the two,about 8%.ZnO nanorods perform slightly better,and the low-temperature and water stability performance are close,about 2%～4%.As an engineering application,considering the performance improvement effect and economy of two different morphologies of nano ZnO on asphalt and asphalt mixture,it is recommended to use 3%ZnO nanorods.