Site performance of galvanic anodes in concrete repairs

Galvanic anodes can be used to limit the extent of concrete replacement and extend the service life of patch repairs to reinforced concrete (RC) structures. They respond to changes in environmental conditions and this attribute has been employed to extend their use. Traditionally, galvanic anodes are installed within the repair area itself. Although simple to install, this has certain limitations however, due primarily to the resistivity of the repair material. A recent alternative has been to install galvanic anodes in pre-drilled cavities in the parent concrete around the perimeter of the patch repair. This paper reviews and compares the performance of discrete galvanic anodes installed both within the repair area and parent concrete in full-scale RC structures. Results indicate that galvanic anodes installed within the parent concrete had a more profound effect on the polarisation of the steel around the perimeter of the patch repair. This provides the empirical basis for alternative designs incorporating galvanic anodes that will enable increased corrosion protection to the steel reinforcement around the patch repair, which is generally considered to be at the highest risk.