Study On The Influence Of Guangxi Humid,heat And Light Coupling Environment On Rubber Modified Asphalt And Mixture Performance

In the typical climatic conditions of high temperature and rain in Guangxi,the asphalt pavement is prone to water damage under the continuous action of traffic load,and the aging of the asphalt pavement caused by UV rays is also very serious.In order to improve the performance of asphalt pavement,it is particularly important to study the effects of water and ultraviolet light on the performance of rubber asphalt and asphalt mixtures in high temperature environments.Therefore,this paper selects self-made water influence freeze-thaw cycle test and ultraviolet light environment simulation box to simulate the actual water effect and ultraviolet aging effect of asphalt pavement,and the alternate test method is used to simulate the coupling effect of moisture,heat and light.After undergoing artificial water affects freeze-thaw cycles and ultraviolet aging,it has passed the three major indicators of asphalt,Dynamic Shear Rheology test(DSR),Bending Beam Rheology test(BBR),respectively,from penetration,ductility,softening point,Indexes such as rutting factor and creep stiffness evaluate asphalt performance changes.The test results show that the high temperature performance of rubber asphalt is improved,but the low temperature performance is reduced.The penetration and ductility of rubber asphalt decrease,the softening point rises,and the penetration index is greatly affected by the time of ultraviolet light.The softening point and ductility index are greatly affected by the number of water affects freeze-thaw cycles;the rutting factor of rubber asphalt increases High,the phase angle decreases,and the temperature effect is the most significant;the creep stiffness of rubber asphalt increases,and the creep rate decreases.Using infrared spectroscopy(FTIR),gel chromatography(GPC),and contact angle test to conduct microscopic observation tests on the aged rubber asphalt.The results show that the proportion of asphaltenes and other macromolecular substances in the asphalt increases significantly after aging,which reduces the viscosity of the asphalt,The elasticity is enhanced,the asphalt becomes harder and brittle,which is manifested by the improvement of the high temperature performance of the asphalt and the decrease of the low temperature performance,which is consistent with the aforementioned macro test results.The rutting test and the low-temperature trabecular bending test were carried out on the rubber asphalt mixture before and after aging.The dynamic stability,flexural tensile strength,and maximum flexural tensile strain were used to evaluate the high temperature and low temperature performance changes of the asphalt mixture before and after aging.The test results show that the flexural tensile strength,and maximum flexural tensile strain of the rubber asphalt mixture decrease with the increase of the number of water affects freeze-thaw cycles and the extension of the UV irradiation time.