Statistical investigation of different analysis methods for chloride profiles within a real structure in a marine environment

Corrosion is a major problem for durability of reinforced concrete structures in a marine environment. To establish the best accurate planning for maintenance operations, assessing chloride ingress within concrete is essential. The present paper reports a study conducted to investigate a large amount of field chloride data collected from a 28-years old beam in a splash zone. The chloride profiles are examined based on Fick's second law to estimate the surface content C-s and the diffusion coefficient D. Firstly, three different cases considering the location of the maximum chloride content are tested: a reference case (individual analysis), a 15-mm discarded case and a 20-mm discarded case (generic treatments). The results highlight the importance of the individual analysis. C-s and D, indeed, appear to be significantly affected by the generic treatment, the relative error being around 50% for C-s and 100% for D. A focus is therefore placed on the individual analysis. The coefficients of variation are 44% and 61% for C-s and D, respectively. For the statistical distribution, both parameters show a clear dependence. They also follow a lognormal law with a mean value ranging between 0.0057 and 0.0085 kg(cl)/kg(concrete) for C-s and equal to 1.3 x 10(-12) m(2)/s for D.