The Study On Mechanical Characteristics And Crack Repair Of Asphalt Overlay On Airfield Pavement

Under the conditions of non-suspending air service and rapid construction,asphalt overlays have been effectively used in the construction of airport pavements,and the use of corresponding composite pavement structures has become increasingly widespread.Due to the load generated by large aircraft and comprehensive effect of external environmental factors and internal material properties,during the service of asphalt overlays,in order to promptly treat the disease and restore the use of overlays,engineers must focus on the mechanical response based on the contact between structural layers and conduct opportune inspections of pavement conditions.Therefore,based on the analysis of the mechanical properties of composite structures,it is important to carry out the research on disease treatment and repair technology of asphalt overlay on airfield pavement.In this paper,it is studied from the aspects of theoretical analysis,structural test and numerical simulation for the complex structure pavement formed by adding asphalt layer to cement concrete.First,according to the structure and use of pavement structures with asphalt overlay at domestic airports,the focus of disease research is on ubiquitous cracks and rutting.The data shows that the cracks accounted for the largest proportion in different disease types,and the existence of reflective cracks and slip cracks is more common;Therefore,they are used as the main object of the disease research,and the corresponding structural mechanical indexes—the tensile stress at the bottom of the asphalt layer and the maximum shear stress between the layers—are given in the subsequent calculation and analysis.Secondly,the research determines the material parameters and boundary constraints of different structural layers according to the actual conditions of the project,and establishes the integrated finite element model of the composite structural road surface including the tie bar and the dowel bar;On this basis,combining the landing gear distribution and load parameters of a large aircraft,the mechanical responses under different combinations of transverse and longitudinal load positions are comprehensively studied,and the change laws of mechanical indexes along longitudinal and transverse directions under the aforementioned conditions are obtained.Then,considering the influence of the contact conditions between layers,the contact element is set at the interface and the cohesive zone material(CZM)model is introduced to perfect the simulation of the interaction between layers.In the structural shear test,the relative shear displacement between layers of different materials can be effectively obtained by capturing the process state of the specimen and collecting data.Thus,the material parameters including the stress intensity and fracture energy,and the stress distribution at the contact surface are calculated.At the same time,it is observed that the micro cracks in the asphalt layer obviously appears to be cracked at the contact surface.Finally,the main points of cracking treatment engineering are analyzed.With the application of filling,the specific structural forms are determined.Combining different forms of applied loads,based on the analysis of interface failures and crack development trends,the main factors affecting the stress status and deformation condition are obtained by using parameter sensitivity analysis,which can provide guidance on the shape control of the slots in construction.In summary,aiming at the treatment problem of asphalt overlays on airport pavement,this research combines the stress characteristics of the overall structure of the pavement,and summarizes the causes of the formation of the disease and the role of influencing factors.The construction technical points and index control proposed reasonable suggestions,which provides a reference for improving the stability and longevity of airport pavement overlays.