Corrosion protection, long-term performance

K. N. Gurusamy and M. P. Geoghegan, The long term performance of embedded reference electrodes for cathodic protection and insitu monitoring of steel in concrete , in Corrosion of Reinforcement in Concrete, edited by C. L. Page, K. W. J. Treadaway and P. B. Bamforth, Elsevier Applied Science, London, UK, 1990, pp 333-347. 

Long term performance of a good coating for corrosion protection requires ... 

P. B. Bamforth, J. Chapman-Andrews, Long term performance of RC elements under UK coastal conditions , Proc. Int. Conf. on Corrosion and Corrosion Protection of Steel in Concrete, R. N. Swamy (Ed.), Sheffield Academic Press, 24-29 July 1994, 139-156. 

Aluminum and aluminum-zinc alloy anodes have become the preferred sacrificial anodes for the cathodic protection of offshore platforms. This preference is because aluminum anodes demonstrate reliable long-term performance when compared with magnesium, which might be consumed before the platform has served its useful hfe. Aluminum also has better current/weight characteristics than zinc. Weight can be a major consideration for large offshore platforms. The major disadvantage of aluminum for some applications, for example, the protection of painted ship hulls, is that aluminum is too corrosion resistant in many environments. Aluminum alloys will not corrode reliably onshore or in freshwater [37]. In marine... 

IS Clift, Corrosion Protection for Water Transmission Pipe a Practical Guide for Long-Term Performance, Price Brothers Company, Dayton, OH, Jan. 2000. 

Penetration of chlorides from seawater with subsequent corrosion of embedded steel represents a serious problem and threat to the durability and long-term performance of many concrete structures in marine environments. Recent field investigations of relatively new concrete structures in Norwegian harbors have shown that chloride-induced corrosion may occur already after a service period of approximately 10 years [1-2]. In order to obtain a more controlled durability and longterm performance of concrete structures in marine environments, a proper durability design should be carried out [3]. As part of such design, surface hydrophobation of the most exposed parts of the structure may be one of several protective measures that should be considered. 

The corrosion rate is approximately linear with time in most aggressive atmospheres (Fig. 2.1 and Table 2.2) hence long-term performance can be predicted if information on behavior over one year—or even less—is available. Milder atmospheres usually will enable zinc to form a more protective patina, and if this happens, corrosion rate decreases with time. 

Requirements specified in this way are deemed-to-satisfy rules. Such rules cannot be used to quantify the performance of the structure in general, specific effects of additional measures (for instance increasing the cover to the steel), or the consequences of sub-standard practice (for example using a higher w/c). In this respect it is important to note that EN 206 also allows the use of alternative performance-related design methods with respect to durability that consider in a quantitative way each relevant deterioration mechanism, the service life of the element or structure, and the criteria that define the end of the service life. Such methods should draw a picture of the characteristics that the concrete must possess to protect the reinforcement for the service life requested from a predictive model of the corrosion attack. These refined methods (as opposed to standard methods) may be based on long-term experience with local practices in local environments, on data from an established performance test method for the relevant mechanism, or on the use of proven predictive models. 

Sohanghpurwalla, A.A., Islam, M. and Scannell, W. (1997). Performance and Long Term Monitoring of Various Corrosion Protection Systems used in Reinforced Concrete Bridge Structures. Proceedings of International Conference Repair of Concrete Structures, from Theory to Practice in a Marine Environment. 

Smith, L.M. and Taylor, M.F. The Long term In-Service Performance of Corrosion Protection to Prestressing Tendons in AGR PCPVS, Joint Wano/OECD-NEA Workshop, Civaux, Poitiers, France, 1997. 

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