| Highway asphalt pavement is subjected to the continuous action of vehicle load in the natural environment,its service performance is declining continuously and the disease continues to develop.Fatigue cracking and permanent deformation are the main diseases of highway pavement.It's very necessary to evaluate the performance of inservice pavement asphalt mixture to resist two diseases.Therefore,in order to accurately evaluate the road performance of highway pavement and optimize maintenance decision,this paper tests and evaluates the fatigue performance and high temperature stability of asphalt pavement in service,and quantifies the fatigue performance and high temperature stability of each road segment.Based on the performance of the pavement material,the difference in road performance between different sections is compared,and the priority ranking of maintenance is optimized.This paper collects the road surface inspection data of Hanshi Expressway and evaluates the pavement performance.It is found that the overall performance of Hanshi Expressway is better,but the pavement surface condition index is lower.And there are more vertical and horizontal cracks on the pavement.The road section that is “excellent” accounts for 50% of the total mileage.On the basis of pavement performance evaluation,the pavement core section was selected and the pavement core sample was drilled.It's found that the thickness of the core sample of the upper layer satisfing the design standard of 4 centimeters account for 12%.For the evaluation of road surface fatigue performance,the uniaxial direct tensile test of different strain levels at 20 °C was carried out on the surface layer and the lower layer of the core sample respectively.According to the modified Paris formula,the Dissipated Pseudo-Strain Energy and apparent stress amplitude are fitted,and the fatigue performance parameter of 9)is solved.The size of the modified Paris formula parameter 9)of the surface layer and the lower layer of different sections is compared.The anti-fatigue cracking ability of the surface layer in the serving highway pavement is better than the lower layer.According to the fatigue life prediction model in the asphalt mixture design specification,the residual fatigue life of each structural layer of the coring section is predicted,and the dynamic modulus of each structural layer of the wheel track is input as a parameter to obtain the maximum bottom tension strain of each structural layer.Under the normal service,the tensile strain generated by the middle layer under the standard axle load is the smallest but the residual fatigue life is the largest.The tensile strain generated by the lower layer is the largest and the residual fatigue life is the smallest.Aiming at the high-temperature stability evaluation of pavement,the rheological number test and the core-like Marshall test are applied to each structural layer of the pavement to study the high-temperature stability.By comparing the number of rheological numbers of the middle layer and the lower layer obtained by the number of rheological tests,the resistance of the middle layer to the permanent deformation is greater than that of the lower layer.The Marshall stability of each structural layer of the core sample is corrected,and the Marshall stability of the upper layer is greater than the design index.The middle layer and the lower layer are both smaller than the design value,and the value of the lower layer is the smallest.Based on the above-mentioned evaluation of fatigue performance and high temperature stability of in-service pavement,a road performance evaluation and maintenance priority method based on pavement material performance was established.Based on the fatigue performance parameters 9),rheological number and the pavement performance,the gray element method and analytic hierarchy process are used to sort the road performance of the core section,and finally the maintenance priority of the coring section is obtained. |
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