Abstract
This paper presents an overview of 30 years' experience with cathodic protection of steel in concrete in The Netherlands. Principles and practical aspects of CP and its design and installation are presented. Three phases have passed from the late 1980s until present: pioneering, development and maturity. In the first period CP was mainly applied to precast elements corroding due to mixedin chlorides. The parties involved worked together to draw up a Technical Guideline. In the second period, application to bridges came up, including post-tensioned structures, which was then innovative. Furthermore, galvanic anode systems were introduced. In the third period, CP became a fully accepted method of securing durability and safety. Renewed collaboration led to a database that allowed analysis of various aspects of CP system working life, including shortcomings in early systems. Major successes and lessons learned will be presented. Technical and non-technical developments are highlighted and some recent innovative CP components and systems are discussed.
Highlights
Increasing numbers of concrete structures develop corrosion of the embedded reinforcement. This is due to prolonged exposure to aggressive influences including chlorides from sea water and de-icing salts or to the effects of mixed-in chlorides; both cases are aggravated by carbonation [1, 2]
This paper addresses some of the history and experience with Cathodic protection (CP) of concrete structures, based on the authors’ involvement in The Netherlands and documentation from other sources
Activated titanium systems perform well over at least 20-25 years in many welldocumented cases; working lives of 25 and more years appear very well possible. This experience is in agreement with a recent study on long term performance of CP systems on motorway structures [14], which showed that conductive coating anodes may work for a very long time, in infrastructural works and despite visible deterioration of the coating
Summary
Increasing numbers of concrete structures develop corrosion of the embedded reinforcement. This is due to prolonged exposure to aggressive influences including chlorides from sea water and de-icing salts or to the effects of mixed-in chlorides; both cases are aggravated by carbonation [1, 2]. Reinforcement corrosion causes cracking and spalling of concrete and steel cross section loss, which compromise serviceability and eventually structural safety. In many cases conventional methods of concrete repair have been found not to be effective or durable [3, 4]. Cathodic protection (CP) on the other hand, has demonstrated to be an effective and durable method for protecting steel in concrete. CP of concrete was developed in the USA in the 1970s [5] and introduced in Europe in the 1980s [6]. Long term performance results and an overview of necessary interventions of large numbers of systems have been published [14, 15]
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