Reliability Research Of Reinforced Concrete Structures Under The Coupling Action Of Load And Chlorine Erosion

At present,the durability of concrete structures is becoming more and more important in the world,which has been paid much attention by scientists and engineers.Load and environmental factors are the main factors influencing the durability of concrete structures,the transmission mechanism of chloride ion in bearing concrete and cracked concrete,and the durability of components reliability calculation and analysis,which has high practical value.In this paper,the research is carried out,and the research contents and achievements are as follows.(1)It analyzed the penetration behavior of chloride ion in concrete systematically.Research has been carried on the permeability of chloride ion in C25 concrete,analyzing what influence of the load size(load ratio 0.3,0.5)and the load type(tensile stress and compressive stress)may have on chloride ion's permeability by using the method of three-point self-anchoring.Based on the regression analysis,the influence of the load level on the diffusion coefficient of chloride ions is obtained,and the existing chloride ion diffusion model is further improved.(2)Studies on the effects of crack width on the osmotic behavior of chloride ion in concrete and the corrosion of steel bars have been done.A series of cracked concrete specimens were prepared by prefabricated fracturing method.The test samples were subjected to 70 days of chloride salt immersion erosion test.The chloride ion content in the surrounding area and the crack depths were observed and analyzed.The fracture and crack width chloride ion transport.The dual porosity model was used to analyze the transport of chloride ion in cracked concrete,and the relationship between the crack width and the apparent chloride diffusion coefficient was established.Based on the measurement and analysis of steel bar corrosion length,the relationship between crack width and crack length at crack section is established.(3)The study has been carried on the durability of concrete structure,which based on chloride diffusion model and crack of concrete chloride diffusion model by improving load.The limit state equation for chloride ion critical concentration and chloride ion concentration on steel bars was established,which applies Monte-Carlo method on corrosion initiation random reliability calculation and analysis of influence of model parameters on durability reliable index.Thus,it provides provide theoretical basis for improving the durability of concrete.