Study On Mechanical Characteristics And Crack Propagation Of Asphalt Deck Pavement Of Cement Concrete Bridge

Bridge pavement system is an important part of the bridge structure, withstanding vehicle loads and temperature changes of sunlight directly, whose forces are more complex than ordinary pavement. Therefore, when we are operating mechanical calculations, the traditional model of pavement structure can not accurately analyze the mechanical properties of the pavement system. Based on the linear elasticity and using ABAQUS finite element software, this thesis simulates bridge projects and establishes a rational three-dimensional model to analyze the pavement stress state of simple asphalt surface hollow by static vehicles, and discusses the crack propagation in pavement by application of the basic theory of fracture mechanics.Firstly, based on a broad understanding of the researches about bridge deck home and abroad, this thesis has drawn on the experience of relevant scholars, summarized the deficiencies of the results and identified technical methods of following studies.Secondly, this thesis has analyzed the specific finding results, summarized the main types and factors of pavement damage and provided indicators and formulas controlling the emergence and development of damage.Thirdly, based on the finite element theory, this thesis has designed the three-dimensional model simulating Zhujiachong Bridge and given various constraints and material parameters. The uniaxial load uses single wheel group and finds the most unfavorable load bit of the bridge pavement by moving load position. Under this unfavorable load bit, it tries to seek the varying parameters which influence the stress and vertical displacement of the surface by changing surface charge material parameters, overloading ratio, friction coefficient and friction coefficient between layers.Fourthly, by application of the basic theory of fracture mechanics, this thesis studies the influence of changes of crack width and pitch and asphalt pavement material parameters on the sheering stress of asphalt pavement system with a gap near the crack tip region when under partial loads. It analyzes the changes of stress intensity factor K//of crack tip Ⅱ in order to judge the changes of its crack propagation rate. It studies the influence of changes of crack width and pitch, pavement material parameters and temp coefficient on the tensile stress of the asphalt pavement system with a gap near the crack tip region when under temperature loads. Besides, it analyzes the changes of stress intensity factor K/of crack tip I to judge the changes of its crack propagation rate.The research of this thesis not only provides an important theoretical reference to the in-depth study of the failure mechanism of bridge pavement, but also gives valuable technical support for using appropriate methods to prevent and crack extension resistance in the design and construction process of bridge pavement.