Lime Addition Effect on Corrosion of Reinforced Mortar

posted on 18.09.2019 by Vanessa de Freitas Cunha Lins, Michele Cândida Carvalho de Oliveira, Cíntia Gonçalves Fonseca Costa, Carlos Roberto Araujo

ABSTRACT This study aims to investigate the effect of lime addition in cement mortar on corrosion resistance of carbon and galvanized steel reinforcements. Mixed mortars were studied containing three contents of lime (6.7, 13.3, and 26.3 wt.%). The water retention, incorporated air, and compression strength of reinforced mortars were determined. Immersion tests were performed using the reinforced mortars consisting of 12 cycles of immersion in a solution of 3.5% (wt./v) sodium chloride and drying in a stove at 60oC. Electrochemical impedance spectroscopy was used to monitoring reinforcement corrosion after cyclic tests. These measurements were repeated after 36 months of the cyclic immersion testing. After the cyclic immersion tests in a saline solution, the polarization resistance of carbon and galvanized steel reinforcement increased as the lime content in mortar increased, demonstrating the protective effect of lime. After 36 months, the polarization resistance of steels in mixed mortars with the highest lime content was the lowest. For the carbon and galvanized steel in cement and mixed mortars, the polarization resistance increased after 36 months of the cyclic test.