Analysis And Expression Of Rutting In Semi-rigid Base Asphalt Pavement Based On Interlayer Contact State

At present,in the design of asphalt pavement,it is generally assumed that the contact state between layers is in a completely continuous state.But in actual operation process of the road,the construction quality control,erosion of water and salt migration,such as temperature and load factors,especially the semi-rigid base between asphalt layer and the surface contact state between evolution and degradation,interlayer performance decay,the contact between the layers are often not completely straight,bring significant effect to pavement structure mechanics response.Rutting is a design control index for semirigid base asphalt pavement.At present,the characterization of rutting mainly considers the influence factors such as pavement material characteristics,load,environment,pavement structure composition,etc.,but does not consider the change of pavement structural mechanical response caused by interlayer contact damage,which leads to insufficient accuracy of rutting prediction.Therefore,it is necessary to study the rut disease development law considering the interlayer contact state,so as to evaluate the rut disease of asphalt pavement more comprehensively and scientifically.Based on the relevant research results at home and abroad,this paper analyzes the influence of the contact state between foundation layers on the rutting development law of typical semi-rigid asphalt pavement with the help of indoor rutting test and finite element numerical simulation technology.Based on this,the rut prediction model proposed by predecessors is improved and perfected,and the expected results have certain academic significance and value for rut prediction research and disease evaluation.The main research contents and conclusions are as follows:(1)The research progress of rutting prediction methods for asphalt pavement is reviewed in detail,and the rutting prediction methods are reviewed.On this basis,it is suggested that it is necessary to consider the interlayer contact state as an important influencing factor in the rutting prediction of asphalt pavement.(2)Analyze the mechanism of rutting on asphalt pavement,summarize the main factors affecting the generation and development of rutting,and sort out the influence of the contact state between asphalt pavement layers on the road structure.(3)By setting different barrier areas between basement layers to simulate the contact states between different layers,indoor rutting test was carried out to analyze the influence of the change of contact states between layers on the rutting.The results show that with the increase of interlayer barrier area,the rutting depth and rutting development rate increase gradually,and the dynamic stability decreases non-linearly.The interlayer contact has a great influence on the rutting resistance of pavement.Therefore,it is necessary to strengthen the control of interlayer bonding to delay the occurrence and development of rutting.(4)The three-dimensional finite element model of semi-rigid pavement structure was established by using the finite element software ABAQUS,and the rutting deformation of asphalt pavement and the shear stress change in asphalt pavement surface based on the contact state between layers were analyzed.The results show that the shear stress reaches its maximum value at about 8cm below the road surface,and maintains a high value in the range of 4cm-10 cm.With the increase of interlayer friction coefficient,rutting deformation and the maximum shear stress in asphalt surface layer decrease gradually,and poor interlayer contact promotes the formation and development of rutting.In the design of asphalt pavement,it is suggested to check and calculate the mechanical indexes in the road structure considering the influence of interlayer contact,so as to achieve a more reasonable design of the pavement structure and reduce the various road diseases caused by interlayer contact in the road operation process.(5)Through numerical analysis,the expression of the relationship between the contact state between layers and the shear stress in the asphalt surface layer is established.Based on the systematic analysis of the permanent deformation prediction model proposed by scholars at home and abroad,the prediction model suitable for this study is selected,and the interlayer contact state is introduced into the original prediction model through the influence of shear stress,so as to realize the further improvement and development of the original prediction model.Finally,the rutting prediction model considering the influence of interlayer contact was verified by using the field measured data of asphalt pavement rutting in the existing literature,and it was found that the measured values were in good agreement with the predicted values,which indicated that the rutting prediction method considering the interlayer contact state was feasible.