The Analysis Of Damage And Cracking In Concrete Pavement Based On Cohesive Zone Model

Based on the theory of fracture mechanics,the fracture and failure behavior of concrete is analyzed.In current analysis and design of concrete pavement structure,the cracking of concrete is usually regarded as brittle fracture of linear elastic material.In fact,as the concrete cracks,a fracture process zone will be formed near the crack tip due to the aggregation of micro cracks,of which the influence on the bearing capacity of the concrete structure should not be neglected.The cohesive zone model can effectively simulate the damage and softening behavior of the fracture process zone of concrete,which has attracted wide attention of domestic and foreign scholars.In this paper,basic theories of fracture mechanics were overviewed firstly,and then the applicability of cohesive zone model to simulate concrete cracking is explained.After the constitutive relation of the cohesive zone model with bilinear damage evolution phase is comprehensively introduced,two finite element models were formed and analyzed,which were a concrete single-notched beam under three-point bending and a concrete pavement slab under edge loading.The main research results are as follows:(1)Through the analysis of literatures,the basic theories of linear elastic fracture mechanics and elastic-plastic fracture mechanics were summarized,of which the applicability in concrete cracking simulation was also analyzed.According to the fracture characteristics,the rationality of the fictitious crack model and the cohesive zone model were explained then.(2)Combined with the common finite element software ABAQUS,the basic theory of the cohesive zone model with bilinear damage evolution phase was comprehensively introduced,and based on the constitutive relation of this model,the significance and selection of the concrete fracture parameters were analyzed.(3)A finite element model of a concrete single-notched beam under three-point bending was formed and analyzed.After the comparison with the existing experimental results,the applicability of the cohesive zone model with bilinear damage evolution phase to simulate concrete cracking was verified,and then the mechanical response and damage development of the beam were analyzed.(4)A finite element model of a concrete pavement slab under edge loading was formed and analyzed.The variation of the stress distribution and the damage development of the concrete slab was analyzed.Finally,the method of determining the ultimate state of bearing capacity of concrete slab was proposed.