Research On Fatigue Life And Maintenance Strategy Of Semi-rigid Base Based On Damage Model

Semi-rigid base asphalt pavement is the main type of pavement structure for high-grade highways in China.Semi-rigid base as the load-bearing layer of asphalt pavement,is generally believed that its fatigue life is greater than the asphalt surface.Many of our high-grade highways have been open for 20 years,and the asphalt surface has been repaired several times.At this time,it is necessary to study the fatigue damage rule,fatigue life and maintenance strategy of the semi-rigid base which have been serving for a long time.The main contents and conclusions of this paper are as follows:Firstly,the three-stage fatigue damage model for semi-rigid base materials is proposed based on the damage mechanics.Then,the fatigue life of the semi-rigid base material is estimated by the Chaboche damage model and the three-stage damage model.The results show that the fatigue life estimated by the three-stage damage model is consistent with the experimental data.Then,the finite element method is used to analyze the semi-rigid base asphalt pavement.The damage changes and stress changes of the semi-rigid base and the semi-rigid subbase under cyclic loading are analyzed.At the same time,the influence of parameters including the modulus,thickness,interlayer contact and other factors on the fatigue damage of semi-rigid base and subbase is also studied.Then,the fatigue damage of the semi-rigid base is observed and verified based on the ALF test,and the prediction formula of the fatigue life for the semi-rigid base is given.Finally,with the fatigue damage D as the evaluation index,maintenance evaluation method of the semi-rigid base is proposed.