Experimental Study On Aging Performance Of Asphalt Mixture And Aging Prediction Model

During transportation,storage,construction and use,the asphalt mixture will be subject to temperature,sunshine,air,traffic and other factors and aging,which will cause the asphalt mixture properties to decay.Thermo-oxidative aging and photo-oxygen aging are two main aspects of asphalt mixture aging research.Based on the analysis of aging of asphalt mixture at home and abroad,this paper takes a modified asphalt AC-13C asphalt mixture commonly used in asphalt pavement surface layer as the research object,through its anti-crack performance and water resistance before and after aging,analyzing damage performance and dynamic modulus test to study the aging law of asphalt mixture.At the same time,using the relevant model to estimate the decay law of performance,and obtaining the decay prediction equation of thermal oxygen aging performance of the corresponding asphalt mixture.Firstly,according to the results of raw material test,the target mix ratio design of AC-13C asphalt mixture was carried out to determine the ratio of each material,the synthetic gradation of mineral materials and the best ratio of oil and stone,and the high temperature stability of the designed AC-13C asphalt mixture was Anti-water damage performance tested.Secondly,based on the aging test methods and aging environment analysis of asphalt mixture at home and abroad,combined with the actual situation of asphalt pavement and the differences of high and low temperature thermal oxygen aging,this paper developed a thermal oxygen aging test program for indoor aging ovens with 85℃,75℃,and 65℃ temperatures.At the same time,it tested the ratios of low temperature splitting strength,normal temperature splitting strength and freeze-thaw splitting strength of asphalt mixture under different aging temperature-time,And analyzed he influence of aging temperature and aging time on the decay of asphalt mixture performance.The experimental results showed that the thermal oxygen aging of asphalt mixture under lower temperature conditions(≤85℃)can be converted by the time-temperature equivalent relationship.Based on the assumption that the initial rate of bitumen aging is the largest and eventually approaches 0,it established the prediction model of thermal oxygen aging of bituminous mixture with asphalt mixture cracking strength,and analyzed the parameters of model equations and using 1stOpt software to analyze and match the parameters of the model equation,and establishing the equivalent time temperature relationship of the asphalt mixture under the condition of low temperature.In order to further study the effect of thermal oxygen aging on the higher temperature performance of asphalt mixture,this paper conducted a dynamic modulus test on asphalt mixture aged 5 days at 85℃ and fresh asphalt mixture to analyze the test frequency,temperature and heat of asphalt mixture.Effects of Oxygen Aging on Dynamic Modulus,Phase Angle and Rut Factor.The results showed that the higher the temperature is,the lower the dynamic modulus is;the dynamic modulus is more sensitive to the change of the temperature in the low temperature range;the frequency is positively correlated with the dynamic modulus;the phase angle is more sensitive to the expansion of the frequency in the high frequency region;the aging of the asphalt mixture The dynamic modulus increases,but the effect on the phase angle is not a single increase or decrease,and the rutting factor of the asphalt mixture increases after aging.