The Research Of Concrete Creep Under Long-term Sustained Load

Concrete as the most widely used artificial stone in civil engineering, it’sdevelopment is very quick and has already become an indispensable material in waterconservancy engineering. In the dam and other hydraulic concrete structure in complexenvironment under gravity, water pressure and temperature stress and other long-termsustaining load during operation. There are obvious differences in the mechanicalproperties of concrete mechanical properties and laboratory test in the complicatedenvironment of concrete. Due to complexity, effects of sustained loading on concretemechanical tests carried out for the inconvenience, the nonlinear creep of concreteunder sustained load and long-term effects of mechanical loading on their own research,research in this area to carry out much-needed.In this paper, the dam and other hydraulic concrete under long-term sustainedloading nonlinear creep as the research object, adopting the analysis method ofcombining experiment and theory, the study of concrete creep high sustained load. Thispaper carried out the following research and obtained some conclusions andachievements.First of all, this paper carried out in different load level under the tensile, uniaxialcompressive creep test, the deformation law of nonlinear creep of concrete wereobtained; in the uniaxial compressive creep test failure process of the law ofdevelopment of the damage of concrete under sustained load with high test method fornonlinear ultrasonic detection. Through a series of experimental study shows that thelong-term deformation properties of concrete high bearing loads is the concrete creepand damage interaction.Then, based on the result of the experiment, analysis of the current creep damagevariable model and macroscopic damage mechanics, That the deformation of concreteunder sustained loading is composed of nonlinear creep deformation and damage, thelinear creep. Establishment of the nonlinear creep model of concrete creep and damageconsidering coupling. By theoretical analysis that the high under sustained loadnonlinear creep, damage of concrete is due to expansion of microcracks caused by. Bycomparing the test and fatigue of concrete, the crack growth rate of nominal stressintensity factor is proportional to the relationship, so as to analyze the deformation andfailure time of concrete and different load levels are calculated under sustained load change with time.