Experimental Research Of Nonlinear Coupling Creep And Damage In Concrete

Contemporary architectural engineering,concrete has become the highest frequency of using,the usage of the largest amount of materials.However,in the complex water conservancy projects such as dams,concrete is often subjected to long-term sustained loading,which is obviously different from the short term load commonly used in the laboratory.Concrete under long-term load will produce creep deformation,which presents some nonlinear characteristics when under high sustained load.The performance of concrete under long-term load as the research object,from the two aspects of concrete creep and damage,study the damage deformation of concrete under sustained load,constitutive model of concrete damage and creep coupling is established,also can provide the references for the actual condition of concrete structure design and safety evaluation.In this paper,the influence of concrete material damage on creep deformation and the damage size in the process of nonlinear creep of concrete are studied.After the initial damage of concrete is been made based on the method of alkali aggregate reaction and the high temperature heating.Than by doing uniaxial compressive experiments and supersonic wave velocity experiments to measure the level of the initial damage of material.In this paper,the influence of initial damage on nonlinear creep of concrete materials is obtained by using the creep tests under different loading levels of concrete materials with initial damage.In this paper,we obtain the initial damage on the influence law of concrete material nonlinear creep,by using pressure testing machine separately to do experiments in different levels of the lotus creep with the initial damage of concrete materials.At the same time during the creep of concrete test,using ultrasonic testing to measure the evolvement rules about the inside damage of concrete,analyzed the time of creep damage when materials under a level high of load,and the correspond to creep deformation,analyzed the influence of creep to concrete materials damage.Combined with the results of damage on the creep test effect,synthesize that the rules-concrete materials under high sustained load-the effect of creep and damage to each other.At the end of the paper summarizes the test conclusion on the basis of Bazant B3 linear creep model,indicating the main factors of damage evolution of materials is concrete creep strain energy accumulation considering the coupling relationship between the creep and damage,nonlinear creep of concrete and the creep damage of statistical damage model is established.