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Working life of cathodic protection systems for concrete structures: analysis of field data

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Author: Polder, R.B. · Leegwater, G. · Worm, D. · Courage, W.
Type:article
Date:2012
Source:3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR 2012, 3-5 September 2012, Cape Town, South Africa, 504-510
Identifier: 465235
ISBN: 9780415899529
Keywords: Materials · Buildings and Infrastructure · Built Environment · Building Engineering & Civil Engineering · BM - Building Materials · TS - Technical Sciences

Abstract

Corrosion of reinforcing steel in concrete structures causes concrete cracking, steel diameter reduction and eventually loss of safety. In infrastructure this is mainly due to penetration of chloride ions from de-icing or marine salts. Conventional repair means heavy, labour intensive and costly work, and economic pressures (time and money) work against the required quality level. Consequently, conventional repair is short lived in many cases in practice. Corrosion reappears quickly and the structure needs to be repaired again after a relatively short time, further increasing life-cycle cost. A completely different situation comes about with Cathodic Protection (CP) of steel in concrete as a repair method. Cathodic protection has been applied to concrete structures with corrosion damage for more than 25 years. This paper reports experience and data of costs for maintaining CP systems, based on an inventory of CP systems in the Netherlands installed between 1987 and 2010. For 105 structures with CP, performance and maintenance data were obtained. The large majority provides corrosion protection for a long time. Degradation of components and overall systems seems to occur in limited numbers. Failure of components and total systems as a function of age is quantified. On the average, the time until minor repairs of parts are necessary is about 15 years. Global failure of the anode, which necessitates near complete replacement of the system, is rare. Based on the statistical analysis of field data, the cost of maintaining a CP system was modelled in terms of life cycle cost.