Model for chloride ingress into reinforced concrete structure under load and marine environment

Abstract

The durability of reinforced concrete structures is very important and becomes serious problems in construction technology nowadays. Many factors, such as concrete proportion, service load and environmental actions that effect on the durability of concrete structure. Particularly, the durability of reinforced concrete structure in marine environment has been reduced quickly. In the past, a large number of prior researchers have introduced the models for chloride penetration into plain concrete and reinforced concrete. However, they have had a disadvantage that almost of simulations are conducted with the pure concrete or uncracked concrete. In fact, in the real structure, most reinforced concrete structures are often exposed and accompanied withcracks that will reduce the durability of reinforced concrete faster than the uncracked concrete case. In this research, the modelswere proposed to predict the chloride ingress throughcracks into reinforced concrete. The chloride diffusivity into cracked reinforced were simulated following one and two dimensions. These modelsare based on the theoretical analysis and experiments of chloride diffusion coefficient and chloride profile.The cracks investigated were the tapered cracks or V-shaped cracks created by the flexural stress to reinforce concrete member. The research showed that in addition to the crack width, the crack depth must be considered as a factor effecting on the chloride penetration depth. The experiments indicated the chloride penetration depth would be increased in increase of the crack depth. The chloride diffusion coefficient was updated as a function of the crack characteristics, crack width and crack depth. The model for two dimensional chloride diffusivity was proposed based on an assumption of the surface chloride content on crack plane and the chloride diffusion coefficient of crack. The predicted results of models fit well with the experimental ones conducted by different methods, the chemical analysis and the electron probe microanalysis.