In this study, corrosion test-data of steel-rebar in concrete were subjected to the fittings of the Normal, Gumbel and the Weibull probability distribution functions. This was done to investigate the suitability of the results of the fitted test-data, by these distributions, for modelling the effectiveness of C 6 H 15 NO 3 , triethanolamine (TEA), admixtures on the corrosion of steel-rebar in concrete in NaCl and in H 2 SO 4 test-media. For this, six different concentrations of TEA were admixed in replicates of steel-reinforced concrete samples which were immersed in the saline/marine and the microbial/industrial simulating test-environments for seventy-five days. From these, distribution fittings of the non-destructive electrochemical measurements were subjected to the Kolmogorov-Smirnov goodness-of-fit statistics and to the analyses of variance modelling for studying test-data compatibility to the fittings and testing significance. Although all fittings of test-data followed similar trends of significant testing, the fittings of the corrosion rate test data followed the Weibull more than the Normal and the Gumbel distribution fittings, thus supporting use of the Weibull fittings for modelling effectiveness. The effectiveness models on rebar corrosion, based on these, identified 0.083% TEA with optimal inhibition efficiency, η = 72.17± 10.68%, in NaCl medium while 0.667% TEA was the only admixture with positive * For correspondence Joshua Olusegun Okeniyi et al effectiveness, η = 56.45±15.85%, in H 2 SO 4 medium. These results bear implications on the concentrations of TEA for effective corrosion protection of concrete steel-rebar in saline/marine and in industrial/microbial environments.

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This paper studied corrosion-inhibition and compressive-strength performances of Na 2 Cr 2 O 7 (sodium dichromate) and C 10 H 14 N 2 Na 2 O 8 ·2H 2 O (ethylenediaminetetraacetic disodium salt: EDTA-Na 2 ) admixtures in steel-reinforced concrete immersed in NaCl and in H 2 SO 4 corrosive environments. Electrochemical methods were used for studying corrosion responses of different concentrations of the individual admixtures and their synergies, in the model that partially replace the toxic Na 2 Cr 2 O 7 by the environmentally-friendly C 10 H 14 N 2 Na 2 O 8 ·2H 2 O, in steel-reinforced concretes. After the electrochemical experiment, the steel-reinforced concrete samples were subjected to the compressive-strength testing and analyses of ASTM C39/C39M-03 and ASTM C267-01(2012). Results showed that the use of environmentally-friendly EDTA-Na 2 for partially replacing toxic Na 2 Cr 2 O 7 chemical exhibited better corrosion-inhibition and compressive-strength improvement in the NaCl-immersed concretes, than in the H 2 SO 4 -immersed concretes. The 2 g Na 2 Cr 2 O 7 + 6 g EDTA-Na 2 admixture (representing partial replacement model of 6 g Na 2 Cr 2 O 7 by 6 g EDTA-Na 2 ) exhibited optimal corrosion inhibition efficiency ( = 99.0%) and very good compressive-strength improvement advantage in the NaCl-immersed concretes. In contrast, comparatively low compressive-strength reduction tradeoff with the good inhibition effectiveness of = 79.9% support use of 6 g EDTA-Na 2 admixture only (i.e., without Na 2 Cr 2 O 7 addition) for inhibiting reinforcing-steel corrosion in the H 2 SO 4 -immersed concretes.Résumé : Le présent article s'intéresse aux capacités d'inhibition de la corrosion et de résistance à la compression d'adjuvants de Na 2 Cr 2 O 7 (dichromate de sodium) et de C 10 H 14 N 2 Na 2 O 8 ·2H 2 O (sel disodique de l'acide éthylènediamine tétraacétique : EDTA-Na 2 ) dans du béton armé immergé dans des environnements corrosifs composés de NaCl ou de H 2 SO 4 . Des méthodes électrochimiques ont été utilisées pour étudier les réponses à la corrosion de ce chacun de ces adjuvants et leurs synergies, dans un modèle où le Na 2 Cr 2 O 7 , toxique, est partiellement remplacé par le C 10 H 14 N 2 Na 2 O 8 ·2H 2 O, plus écologique, dans des échantillons de béton armé. À la suite de ces manipulations électrochimiques, ces échantillons ont été soumis à des essais et analyses de résistance à la compression de type ASTM C39/C39M-03 et ASTM C267-01. Les résultats obtenus ont montré que l'utilisation de l'écologique EDTA-Na 2 pour remplacer partiellement le toxique Na 2 Cr 2 O 7 permettait davantage d'améliorer l'inhibition de la corrosion et la résistance à la compression dans le cas des bétons immergés dans le NaCl que dans celui des bétons plongés dans le H 2 SO 4 . L'adjuvant composé de 2 g de Na 2 Cr 2 O 7 et de 6 g de EDTA-Na 2 (modèle de remplacement partiel dans lequel on substitue 6 g d'EDTA-Na 2 à 6 g de Na 2 Cr 2 O 7 ) montre une efficacité optimale d'inhibition de la corrosion ( = 99,0 %) et entraîne une nette amélioration d...

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