Investigation On The Performance Degradation Of Asphalt Mastic And Vulnerability Partition With Large Temperature Difference

The temperature fluctuation of day and night will cause the high temperature stress of asphalt pavement,especially in the area with large temperature difference,which will seriously affect the durability of asphalt pavement.At present,researchers generally use meteorological indicators to classify areas with large temperature differences,but the asphalt pavements have not been partitioned based on the performance decay characteristics of asphalt materials under large temperature differences.In addition,at present,the research on the decay characteristics of asphalt pavement caused by large temperature difference is mainly limited to the actual pavement disease investigation,the simulation and prediction of asphalt pavement temperature field,and the structural adaptability analysis of asphalt pavement,etc.The performance decay law of asphalt pavement is not clear,which cannot provide a theoretical basis for the durability improvement of areas with large temperature difference.Therefore,this paper determined the indoor test temperature conditions through the analysis of the representative urban surface temperature difference data,taking asphalt mastic as the research object to carry out temperature difference cycle test;The rheological properties,interfacial properties,fatigue-self-healing properties and micro-damage properties of asphalt mastic under temperature difference were studied by macroscopic-microscopic method;Based on the sensitivity of asphalt mastic damage parameters,the vulnerability index of large temperature difference was proposed,and the vulnerability regions of large temperature difference in China were divided.Specific research contents and results are as follows:Firstly,the representative cities in China were selected based on the highway natural area division criterion and the land surface temperature was analyzed statistically.The generalized extreme value distribution model is used to determine the day-night temperature difference obeying Weibull distribution,and the 95% points value is selected as the threshold of extreme diurnal temperature difference.Based on this,the distribution characteristics of extreme diurnal temperature difference representing cities are analyzed.Finally,the temperature condition of indoor temperature difference test is determined according to the distribution interval of surface temperature of representative city.Secondly,the dynamic shear rheometer was used to analyze the effect of temperature difference on the rheological properties,interface properties and fatigue self-healing properties of matrix asphalt paste and SBS modified asphalt paste,and the rheological properties of asphalt slurry,interface properties and fatigue properties of asphalt paste and the correlation between the number of temperature cycle and temperature cycle conditions are established.The effect of temperature difference on the macroscopic properties of different types of asphalt is clarified.Then,atomic force microscopy(AFM)was used to analyze the evolution behavior of asphalt slurry microstructure before and after temperature difference,and the influence of temperature difference cycles and temperature difference conditions on asphalt slurry microstructure surface morphology and microstructure mechanical properties was discussed.The evolution process of asphalt mastic chemical composition before and after temperature difference was analyzed based on Fourier Transform Infrared Spectrometry(FIR).The results showed that asphalt mastic aging phenomenon occurred after temperature difference cycle,and the evolution mechanism of asphalt mastic micro-surface morphology was revealed.Finally,based on macro-micro test results,the indexes representing the damage characteristics of asphalt mastic were selected,according to the sensitivity analysis of asphalt mastic damage characteristic index,extreme diurnal temperature difference and daily surface temperature are determined as the temperature sensitivity factors of asphalt mastic damage,and the vulnerability zoning criterion for large temperature difference of asphalt pavement is determined.At the last,the vulnerability zone map of asphalt pavement under large temperature difference in China is drawn.