Lime Addition Effect on Corrosion of Reinforced Mortar

Resumo

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.
Keywords: Lime. Mortar. Reinforcement corrosion. Electrochemical impedance spectroscopy.