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This paper describes the findings of the experimental works undertaken to investigate the performance of zinc-rich paint (ZRP) to 6 provide cathodic protection to chloride-contaminated RC structures. The program of experimental works was designed and conducted to 7 assess four principal properties, viz (1) conductivity, (2) adhesion with concrete (short term and long term), (3) durability, and (4) electro-8 chemical polarization. These properties considered together define the ability and effectiveness of the materials to act as an anode for 9 impressed current cathodic protection. The research findings indicated that a specific proprietary ZRP product showed that optimum con-10 ductance was obtained with three coats producing a 280-320 μm thickness, with good adhesion to the concrete substrate, in which values 11 obtained ranged between 1.65 and 3.5 MPa with and without applied current. It was capable of withstanding/supporting high levels of current, 12 i.e., more than 300 mA=m 2 , and the service life of the ZRP coating was estimated to be well in excess of 20 years at an applied current density 13 of 10 mA=m 2 .

The Midland Links motorway viaducts (MLMV) are a series of reinforced concrete structures comprising 21 km of elevated motorway around the outer circumference of Birmingham. Deterioration was identified early in their serviceable life due to chloride induced corrosion of the steel reinforcement. An electrochemical treatment utilising an impressed current cathodic protection (ICCP) was successfully trialled in 1987 with the first large-scale commercial application of the treatment on the network in 1991. Since then it has been the principal corrosion management strategy for the MLMV, with 740 structures currently protected by ICCP. The aim of this paper is to offer a brief historical review of the MLMV network, discuss the deterioration mechanisms and review the historical developments of ICCP together with its overall performance as a corrosion-management method. Recent developments in cathodic protection technology and secondary beneficial effects of the ICCP previously not recognised are also discussed on how they can potentially result in significant cost savings for maintenance agencies for this and other similarly protected structures.

Corrosion is a worldwide problem and costs billions of pounds. The corrosion problem is not something new but awareness of the problem in association with civil engineering structures, particularly reinforced/prestressed concrete highway bridges, multi-storey car parks and buildings, is relatively new. Corrosion is insidious in nature and the corrosion of steel in concrete is only apparent when it is quite advanced and manifests itself progressively in the form of ‘rust’ stains, cracking, delamination and finally spalling with exposed and corroding steel reinforcement. The proper application of available science and technology can save a large amount of waste due to corrosion. Over the last two decades a number of corrosion mitigation techniques have been developed. Some are more successful than others. Cathodic protection is the only proven technique for stopping the corrosion of steel in chloride-contaminated concrete.