Effect of C5H11NO2S on reinforcing-steel corrosion in concrete immersed in industrial/microbial simulating-environment

Abstract

In this paper, C5H11NO2S (Methionine) effect on reinforcing-steel corrosion in concrete immersed in 0.5 M H2SO4, simulating industrial/microbial environment, was studied by electrochemical techniques of open circuit potential and corrosion rate. The corrosion test-data were subjected to statistical distribution and tests of significance analyses prescribed by ASTM G16-95 R04. From this, analyzed results showed that the corrosion rate test-data followed the Weibull more than the Normal while the corrosion potential test-data followed both distributions. In spite of these, both the corrosion potential and the corrosion rate models still find agreements in corrosion criteria classification for the tested samples. Samples with C5H11NO2S admixture exhibited corrosion rate reductions compared to the control samples. By this, 0.25% C5H11NO2S admixture (i.e. wt% cement) exhibited optimal inhibition efficiency, η = 87.95 ± 7.64%, on steel-rebar corrosion in the 0.5 M H2SO4-immersed concrete. Experimental data fitted Flory-Huggins adsorption isotherm that indicated physisorption as the prevailing mechanism of C5H11NO2S corrosion-protection on the reinforcing-steel in the industrial/microbial simulating-environment.