Research On Chloride Diffusion And Durability In Concrete Members Considering Effects Of Reinforcement Presence

Reinforced concrete structures are widely used in port, coastal and offshore engineering. Experience of using RC structures shows that durability of RC structures under marine environmental has become a very serious problem that we must face when design and maintain coastal engineering structures. Although researchers have conducted a lot of research on the durability of concrete structure, the research are not comprehensive due to the complexity of the problem. For the research on chloride ion erosion, the chloride diffusion models obtained mostly ignore the impact of reinforcement presence and the particularity of the chloride ion diffusion in the area from the apex of rebar to the surface of concrete. On the basis of summarizing the predecessors' research, this paper has made some exploration on the impact of reinforcement presence and the particularity of the chloride ion diffusion in the area from the apex of rebar to the surface of concrete through experiments and finite element analysis. The main research content is as follows:(1)A lot of research on chloride ion diffusion mechanism of predecessors' are integrated, compared and analyzed. The differences and specific application conditions of the models are cleared. The latest achievements of our research group are introduced to give reasonable chloride diffusion models.(2)For the particularity of the chloride ion diffusion in the area from the apex of rebar to the surface of concrete, experiments were carried out. The chloride concentrations at different depths of concrete were measured. Test data were analyzed from two aspects(aggregate intrusion and Debye-Huckel). A chloride diffusion model considering depth-dependent characteristics is proposed.(3)Experiments of chloride diffusion considering reinforcement presence were carried out. Chloride concentrations at the apex of rebar were measured. Direct and indirect effects of reinforcement were revealed by comparing chloride concentrations at the apex of rebar and that at the corresponding depth in plain concrete. A chloride diffusion model considering reinforcement presence is proposed.(4)Chloride concentration distribution was numerical simulated by using the thermal analysis module of ANSYS software. Research results of depth-dependent characteristics were used to perfect the numerical model. Influence factors such as diameter, space between, cover thickness, surface concentration, diffusion coefficient were researched.