Electrical resistivity model for quantifying concrete chloride diffusion coefficient

The effects of chloride salts on concrete durability have been financially and logistically overwhelming. Current test methods for quantifying diffusivity of chlorides in concrete are time consuming and demanding. A comprehensive electrical resistivity model has been developed to quantify the chloride diffusion coefficient of concrete. The model employs the modified Nernst-Einstein equation along with an ionic concentration sub-model, a pore solution conductivity sub-model, and a binder hydration sub-model. The sub-models, which account for the concentrations of Na+, K+, Ca2+, and OH− ions in the pore solution derived from the binder degree of hydration, binder chemical composition, and alkalis binding to the cement hydration products, are included to accurately quantify the conductivity of the pore solution. Moreover, an experimental program was developed to verify and validate the accuracy and completeness of the electrical resistivity model. The experimental variables are volume fraction of coarse aggregate, water to binder ratio, total binder content, and silica fume (SF) and ground granulated blast furnace slag (GGBFS) as supplementary cementing materials (SCMs). The model results are found statistically equal to experimentally quantified chloride diffusion coefficient values and possess high accuracy and precision for a wide range of concrete mixture, binder composition and age.