Corrosion test-data modelling for C10H18N2Na2O10 performance on steel-rebar in 3.5% NaCl-immersed concrete

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. © 2015 by Nace International