Investigation On The Coupled Aging Behaviors Of Ultraviolet Light With A Range Of Solutions On Asphalt

At present,the research on asphalt aging is mostly limited to single factor thermo-oxidation conditions,ultraviolet irradiation conditions or water conditions.In the actual service process,asphalt is coupled by a variety of factors,so the multi-factor coupling condition is closer to the actual aging of asphalt.In this paper,nine groups of aging environments with UV radiation and different aqueous solutions were simulated.The aging time was 3,6 and 9 days respectively.The multi-factor aging mechanism of asphalt and the properties after aging were studied.Firstly,the macroscopic properties of aged asphalt were studied.The surface morphology of aged asphalt shows that the surface of asphalt changes after aging,and the pores with different sizes appear with the increase of aging time.The surface morphology of asphalt is most significant in UV+4%Na₂CO₃ solution environment;softening point The test results and rheological property test results show that the aged aging asphalt with aqueous solution is higher than the pure ultraviolet aging asphalt;the aging asphalt with high concentration of the same solution has a high degree of aging;the acid and alkali solution are aged more than the neutral solution.High;under the action of single factor UV,the growth rate of asphalt aging rate becomes slower with the increase of time;while the aging rate of asphalt increases under the condition of UV plus solution coupling.The chemical structure and microscopic composition of the aged asphalt were then analyzed.The results showed that the trend of carbonyl gene(I_C=O)and colloidal instability index?Ic?was consistent with the macroscopic performance trend.The formation of sulfoxide gene(I_S=O)sulfoxide group was mainly caused by UV,but the different solutions were not obvious.It is not suitable to judge the degree of asphalt aging under this condition.The results show that the UV aging effect has a great influence on asphalt in the early stage of aging.With the increase of time,the coupling aging of the solution becomes more and more significant.Finally,chemical composition analysis was performed on the residual solution of the same aging condition.The pH test showed that acidic substances were formed in the solution.The total organic carbon analysis showed that the organic carbon was dissolved in the solution.The infrared spectrum analysis showed that the substances in the recovered solution may have alkanes,aromatic hydrocarbons,sulfoxides,amines,amides,carboxylic acids.And ether.The aqueous solution which is acidic after aging does not contain an amine,and the alkaline aqueous solution does not contain a carboxylic acid.