Steel Corrosion Inhibitors in Cement Based Materials from Nopal Slime

Abstract

This research includes results on the corrosion performance of reinforcing steel in cementbased mortar (pH ~ 13) when cactus (Opuntia Ficus Indica -Nopal) slime was used as an addition. The cactus slime addition was mixed at different concentrations by mixing water mass (0%, 1.5%, 4%, 8%, 42%, and 95%). Half-cell potentials and LPR measurements were performed at different time periods to characterize the possible corrosion inhibiting effect of the cactus additions tested. Results showed good corrosion inhibiting effect of Nopal slime on reinforcing steel, in all tested solutions, when chloride ions were present. The addition of such cactus led to an apparent formation of a denser and more packed oxide/hydroxide surface layer on the steel surface that decreased corrosion activity. This oxide/hydroxide layer growth was confirmed from microscopic evaluation of the metal surface layer performed at the end of the research program. The preliminary findings suggest that adding Nopal slime in concentrations between 4% and 8%, by water mass, might be suitable for durability enhancing applications in cement-based mortar.

Electrochemical Evaluation of Opuntia Ficus and Tobacco Waste Extracts as Corrosion Inhibitors on Mild Steel in NaCl and HCl Solutions

“…Inhibitors are chemicals that offer protection to metals against electrochemical attack of aggressive solutions, however, substances such as chromates, nitrates, polyphosphates and lead compounds were used in the past for good efficiency, but actually are considered highly toxic and aggressive to the environment (1). Vegetable plants and recycled materials are being studied for their antioxidant properties and corrosion inhibiting and as processing aid in the preparation and structural strength of concrete (2), the anti-corrosion coatings industry (3.4) or the application of extracts chlorinated inhibitors in acid (6,7) and neutral (5,6) environments.…”

“…In this work we used electrochemical methods to evaluate the properties of the extracts of Opuntia Ficus (nopal mexican) and tobacco waste reported as corrosion inhibitors and low environmental impact (2,3).…”