Abstract

This paper studies the empirical and correlation modeling of corrosion test-data for detailing C₁₀H₁₈N₂Na₂O₁₀ (ethylenediaminetetraacetic disodium salt) performance on steel-rebar corrosion in 3.5% NaCl-immersed concrete. The corrosion test-data were measured using three non-destructive electrochemical-monitoring-techniques from duplicated samples of the NaCl-immersed steel-reinforced concrete slabs admixed with different C₁₀H₁₈N₂Na₂O₁₀ concentrations. Empirical data from these were subjected to statistical-distribution fitting analyses as per ASTM⁽¹⁾ G16-95 R04. Results revealed that corrosion rate from LPR technique correlated excellently (R² = 90.85%; ANOVA p-value = 0.0174) with exponential function of C₁₀H₁₈N₂Na₂O₁₀ molar-concentration and noise-resistance obtained from the other two techniques. Analyzed experimental data and correlation fitting predictions both identified; in agreements, the 0.0224M C₁₀H₁₈N₂Na₂O₁₀ with optimal steel-rebar corrosion inhibition performance. Also, both experimental and correlated prediction models obeyed the Langmuir adsorption isotherm with excellent model-efficiencies, R² = 99.94% (experimental) or R² = 99.98% (predicted). Evaluated isotherm parameters from both models suggested favorable adsorption and predominant chemisorption mechanism by C₁₀H₁₈N₂Na₂O₁₀ inhibitor of concrete steel-rebar corrosion in the saline/marine simulating environment. These bare implications that corrosion monitoring techniques that were technically simple to undertake exhibited correlation with corrosion rate from LPR and, by this, found suitability for indicating absolute corrosive activity of concrete steel-rebar in aggressive medium.