Title: Functionality of Zinc Anodes in Repaired Concrete

Author(s): Ahmed G. Bediwy, M. T. Bassuoni, Martin Beaudette, and David W. Whitmore

Publication: Materials Journal

Volume: 119

Issue: 1

Appears on pages(s): 105-116

Keywords: halo effect; repair; resistivity; zinc anodes

DOI: 10.14359/51734298

Date: 1/1/2022

Abstract:
Zinc anodes are an effective and economical method to prevent and control the corrosion of steel bars. They supply the bars with cathodic current, which can provide corrosion protection at low current densities in the range of 0.2 to 2 mA/m2. The efficacy of zinc anodes is affected by the resistivity of concrete or cementitious repair material in which these anodes are embedded. Limited data is available on the maximum electrical resistivity of repair materials/concretes beyond which zinc anodes cannot properly function to prevent corrosion. In this study, concrete slabs were cast to simulate partial- and full-depth repair configurations. Key variables included resistivity and anode position. Resistivity of the repair section varied from 10,000 to 50,000 Ω-cm, with three anode positions: 25, 100, and 250 mm in the repair section. Analysis of data shows the effectiveness of anodes at controlling corrosion, even in repair concrete with high resistivity.