Effect of inhibitors on the corrosion of galvanized steel and on mortar properties

This work evaluates two complementary protection methods for steel in concrete: galvanizing coating and corrosion inhibitors. The study was undertaken to evaluate the efficiency of using inhibitors (sodium nitrite, diethanolamine) to protect galvanized reinforcements embedded in mortar against corrosion, and their effect on the mortar properties before and after exposure to chloride environments. Accelerated corrosion tests were performed on mortar specimens by wet-dry exposure to sodium chloride solution. The electrochemical behavior of rebars was studied using Electrochemical Impedance Spectroscopy; the results showed that diethanolamine improves the level of protection of the reinforcement. The influence of inhibitor additions on mortar properties was considered by characterizing the pore structure using Mercury Intrusion Porosimetry and by assessing the dielectric properties of mortar employing Impedance Spectroscopy. The results revealed that inhibitors addition leads to microstructural changes. Differential Scanning Calorimetry was applied on mortar samples to elucidate the causes of the observed microstructural changes. (C) 2012 Elsevier Ltd. All rights reserved.