Towards arresting reinforced concrete corrosion – a review

¹ AECOM Ltd, Colmore Plaza, 20 Colmore Circus Queensway, Birmingham, B4 6AT, U.K.
² Loughborough University, School of Architecture, Building and Civil Engineering, Loughborough, LE113TU, U.K.
³ Concrete Preservation Technologies, University of Nottingham Innovation Lab, Nottingham, UK, NG7 2TU

Abstract

This work reviews developments in the understanding of chloride induced corrosion of steel in concrete from both a kinetic and thermodynamic perspective. Corrosion damage is at least in part attributed to the production of acid at sites of corrosion initiation. Solid phase inhibitors provide a reservoir of hydroxyl ions to inhibit damage. Pit re-alkalisation is identified as an important protective effect in electrochemical treatments used to arrest corrosion. A process like pit re-alkalisation is achieved more easily by impressing current from sacrificial anodes using a power supply which may then be followed by low maintenance galvanic protection to prevent local acidification. Methods for monitoring the steel corrosion rate in electrochemically treated reinforced concrete have been developed and used to assess corrosion risk. Some of these concepts have been adopted in the recent international standard on cathodic protection, ISO 12696:2016, some of the amendments of which are considered in the work presented here.