Models for Chloride Diffusion Coefficients of Concretes in Tidal Zone

In a marine environment, reinforcement corrosion due to chloride attack is the most important degradation process of reinforced concrete. Diffusion models found in the bibliography show opposite results, over or underestimating chloride diffusion coefficient values for tidal zone concretes. In this paper the chloride penetration rate for tidal zone concretes has been modeled from data collected from a high number of references, covering a wide range of concrete qualities and not considering accelerated test results. Also, this model has been checked with experimental results obtained from five Spanish maritime structures. The basic parameters considered in this model were water-cement ratio (w/c), type, and content of mineral admixtures. Finally, the efficiency factors of fly ash and silica fume (their contribution to chloride permeability) have been calculated.