Responsive behaviour of galvanic anodes in concrete and the basis for its utilisation

In this study, a unique concrete specimen was used to analyse the response of embedded sacrificial zinc and steel anodes to rainfall and fluctuations in temperature. Current from the zinc and steel anodes increased when the environment was aggressive, showing that the required protection current depends on the present level of corrosion risk. A basis for using the ‘responsive behaviour’ of galvanic anodes is provided by the protective effects of pit re-alkalisation and pH maintenance. By contrast, protection based on achieving adequate polarisation inhibits the use of responsive behaviour and galvanic anodes might only deliver adequate polarisation in aggressive environments.

► The experimental sample had a unique design and was used to investigate the relationship between corrosion risk and galvanic current. ► Steel corrosion current and zinc anode protective current respond to environmental changes. ► The protective effects of pit re-alkalisation and pH maintenance provide a basis for utilising responsive behaviour. ► Protection based on achieving adequate polarisation inhibits the use of responsive behaviour.