Mechanical Behavior Analysis On The Airport Composite Pavement

The pavement structure of civil airport in China is mainly cement concrete pavement structure,and asphalt concrete pavement only accounts for about 10%.With the old cement concrete runway reaching the end of its service life and the increasing traffic volume of flights,the existing cement concrete pavement urgently needs to be renovated.Asphalt concrete pavement overlaying has become the most commonly used renovation method at present.Due to the lack of systematic research on mechanical behavior of airport composite pavement and sufficient theoretical support,rutting and slip cracks are common in some asphalt pavement overlaying projects.Therefore,it is necessary to analyze the mechanical behavior of composite pavement structure under aircraft load.Based on the data of damage investigation of domestic composite pavement,the paper summarizes and analyses the damage of domestic composite pavement structure,establishes a three-dimensional numerical simulation analysis model,builds a full-scale composite pavement structure for accelerated loading,and obtains the mechanical response of composite pavement structure.The results are as follows:1.The main damage modes of composite asphalt pavement and the spatial distribution of diseases are obtained.There is a positive correlation between crack diseases and load action.Rutting is directly related to aircraft load.There is no significant correlation between loose disease of asphalt pavement and load,and it is related to ultraviolet aging.At the same time,loose range and degree are positively correlated with airport service time.2.The stress distribution and influencing factors in the overlay are obtained.The state of interlaminar bonding between asphalt overlay and cement slab and whether horizontal stress is applied on aircraft wheel load have significant effects on transverse and longitudinal tensile strain and bottom tensile strain in asphalt overlay.The bending and tensile stress of the bottom of cement slab is significantly affected by the thickness of the slab and the interlaminar state of cement slab and water-stabilized base.The interlaminar bonding between asphalt overlay and cement pavement is very important to improve the rutting resistance of composite pavement.Interlayer slip + lateral horizontal force + high temperature environment is the most disadvantageous condition for slip cracking of asphalt overlay.3.Obtain the corresponding law of measured road surface.The relationship between measured rutting deformation and loading times can be divided into three stages: the first stage-Volume compaction stage,the second stage-slow growth stage,and the third stage-significant growth stage,in which temperature growth has a significant impact on deformation.Whether the vertical deformation is uplift or depression,the main deformation is concentrated in the middle and lower layers.The influence of interlaminar bond state on strain response is considerable,which is consistent with the conclusions of finite element method.Therefore,the interlaminar bond state should be paid attention to in pavement design.Results of this paper reveal the internal mechanical response and characteristic of composite pavement structure under aircraft load,which provides a basis for the design index of composite pavement structure.