Time-dependent characteristic and similarity of chloride diffusivity in concrete

Abstract

Corrosion of reinforcing steel due to chloride attack is the main cause of deterioration of reinforced-concrete (RC) structures in a chloride environment. Chloride diffusion in concrete is time-varying and affected by many factors. It is necessary for service life prediction of RC structures to make clear how chloride diffusion coefficients change with time. In addition, the test environment has an obvious effect on the concrete's diffusivity, especially on the chloride diffusion coefficient and the age factor. Therefore, it is advisable to conduct similarity analysis of chloride ingress into concrete between an artificial simulated environment and a field marine environment. Based on the existing field exposure test, an accelerated simulated test with the same concrete mixture proportions as the exposure test under a tidal environment were designed in this paper. The free chloride concentrations in concrete with different exposure times and diffusion coefficients of concrete were obtained, and the relationship between the age factor and water/cement ratio was analysed. Finally, the similarity of the time-dependent characteristic of chloride ions in concrete between the accelerated simulation and field exposure test was investigated.