Total-corrosion effects of Anthocleista djalonensis and Na2Cr2O7 on steel-rebar in H2SO4: Sustainable corrosion-protection prospects in microbial/industrial environment

Abstract

This paper studies total-corrosion effects of Anthocleista djalonensis (green natural-plant) and Na2Cr2O7 (well-known inhibitor, but environmentally-hazardous chemical) on steelreinforcement in concrete immersed in 0.5 M H2SO4, simulating microbial/industrial environment. Equal-mass models of the plant leaf-extract and of Na2Cr2O7 were employed as admixtures in steel-reinforced concrete samples immersed in the test-system, from which macrocell corrosion measurements were obtained and analysed as per ASTM G109-99a. Results showed that only the 3.33 g/L Anthocleista djalonensis, among the equal-mass models of leafextract and the chemical admixtures, was outperformed by the 3.33 g/L Na2Cr2O7 in total corrosion reduction effects. In the study, 5.00 g/L Anthocleista djalonensis exhibited optimal effectiveness, η = 93.77%, on the total-corrosion effect of concrete steel-reinforcement. The many Anthocleista djalonensis admixtures that exhibited better inhibition than Na2Cr2O7 admixtures indicates positive prospects of the plant as an eco-friendly and sustainable corrosionprotection alternative for the toxic chemical in microbial/industrial environment.