Mechanical Engineering Department, Covenant University, Ota, Nigeria; Chemical, Metallurgical and Materials Engineering Department, Tshwane University of Technology, Pretoria, South Africa
Okeniyi, J.O., Mechanical Engineering Department, Covenant University, Ota, Nigeria; Loto, C.A., Mechanical Engineering Department, Covenant University, Ota, Nigeria, Chemical, Metallurgical and Materials Engineering Department, Tshwane University of Technology, Pretoria, South Africa; Popoola, A.P.I., Chemical, Metallurgical and Materials Engineering Department, Tshwane University of Technology, Pretoria, South Africa
In this paper, electrochemical techniques were employed to study performance of different concentrations of Anthocleista djalonensis leaf-extract admixtures on the corrosion of steel-reinforcement in concrete immersed in 3.5 % NaCl, for simulating saline/marine environment. Analysed test-results showed that the corrosion rate correlated directly with admixture concentration and inversely with cube of the ratio of standard deviations of corrosion potential and corrosion current. The 0.4167 % A. djalonensis (per weight of cement) exhibited optimal inhibition efficiency, g = 97.43 ± 1.20 %, from analysed experimental data, or 94.80 ± 3.39 %, from predicted correlation model, on steel-reinforcement corrosion in the medium. The other admixture concentrations also exhibited high efficiencies at inhibiting steel-reinforcement corrosion in the chloride contaminated environment. Isotherm fittings of he experimental and predicted performance suggest that they both obeyed the Langmuir adsorption model. Evaluated parameters from the isotherm model indicated favourable adsorption and predominant chemisorption mechanism by this environmentally-friendly inhibitor of steel-reinforcement corrosion in the saline/marine simulating- environment. © 2014, The Indian Institute of Metals - IIM.