Steel is usually protected from corrosion when embedded in concrete, however the ingress of sea salt in coastal areas or use of chloride contaminated constituents in the concrete mix can lead to depassivation and corrosion of the steel. A permanent repair is difficult since, to be fully effective all chloride contaminated concrete must be removed.

Cathodic protection is a well established technique for preventing corrosion of steel work in acidic and chloride infested conditions. Due to problems with de-icing salt attack in North America, cathodic protection is now being used to protect reinforced concrete bridge decks from chloride induced corrosion. Over 50 systems were installed up to 1985 and over 100 systems are being installed in 1985/86. These systems all require installation of conductive groundbeds which can add significantly to the dead load.

This paper describes the research undertaken on conductive coatings for use as impressed current cathodic protection groundbeds. The development of the system is described along with designs, installations and performance of trial installations in the UK and in Australia.

Subject
Electric current, Steel structures, Anode potential, Voltage, Cathodic protection, Groundbeds, Installation, Steel, Instant off potential, Chlorides, Half cell potential, Half cells, Concrete
© 1987 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1987
Association for Materials Protection and Performance (AMPP)
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