Cathodic Protection of Steel in Concrete

The two types of cathodic protection are (i) sacrificial anode and (ii) impressed current systems. 

El-Shazly, Cathodic Protection of Steel in Concrete, 24th Annual Conference on Corrosion Problems in Industry, Egyptian Corrosion Society, 5-8 December 2005, Les Rois Hotel, Egypt. 

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The most recently developed anode for the cathodic protection of steel in concrete is mixed metal oxide coated titanium mesh The anode mesh is made from commercially pure titanium sheet approximately 0-5-2mm thick depending upon the manufacturer, expanded to provide a diamond shaped mesh in the range of 35 x 75 to 100 x 200 mm. The mesh size selected is dictated by the required cathode current density and the mesh manufacturer. The anode mesh is supplied in strips which may be joined on site using spot welded connections to a titanium strip or niobium crimps, whilst electrical connections to the d.c. power source are made at selected locations in a suitably encapsulated or crimped connection. The mesh is then fitted to the concrete using non-metallic fixings. 

In recent years, there has been interest in using zinc as a power-impressed anode for the cathodic protection of steel in concrete. The zinc is flame sprayed onto a grit blasted concrete surface to a final film thickness of approximately 250 m. A primary anode is necessary. Early systems used brass plates as the primary anode, but more recent systems used platinised titanium or niobium wire anodes as the primary current conductor. 

Wyatt, B. S., Anode Systems for Cathodic Protection of Steel in Concrete , paper 23, Cathodic Protection Theory and Practice, 2nd International Conference, Stratford-upon-Avon, UK, June (1989)... 

P. Pedeferri, G. Mussinelli and M. Tettamanti, Experiences in anode materials and monitoring systems for cathodic protection 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 498-506. 

P. Pedeferri, E. Redaelli, Cathodic protection of steel in concrete and cathodic prevention . Final project report 15, COST 521, Luxembourg,... 

M. Tettamanti, P. Pedeferri, Cathodic protection of steel in concrete , Materials Performance, 1988, 27 (9), 18. 

D.A. Hausmann, Criteria for cathodic protection of steel in concrete structures. Mater. Prot. 8 (1969) 23-25. 

Standards and guidance documents for cathodic protection of steel in concrete... 

There are two major international standards on cathodic protection of steel in concrete, RP0290 2000 from NACE international and BSEN12696 2000 from CEN which is discussed in the next section. Both were reaffirmed in 2005 although revised documents are being worked on. Both are aimed at atmospherically exposed steel in concrete. 

BSEN12696 (2000). Cathodic Protection of Steel in Concrete. British Standards Institute, London. 

Cathodic protection is typically used as a rehabilitation technique, but is also used in new construction. The steel in the concrete is made into a cathode and thus its corrosion rate is kept low. Broomfield reviewed the current state of cathodic protection systems in the United States [621. Further information can be obtained from a SHRP report on cathodic protection of concrete structures [63], NACE International holds symposiums on cathodic protection of steel in concrete on a biannual basis [641. 

Cathodic protection of steel in concrete using Mg alloy anode... 

Parthiban G T, Parthiban T, Ravi R, Saraswathy V, Palaniswamy N and Sivan V (2008), Cathodic protection of steel in concrete using magnesium alloy anode . Corrosion Science, 50, 3329-3335. 

Robinson, R. C., "Cathodic Protection of Steel in Concrete," Corrosion of Metals in Concrete, SP49, Detroit, American Concrete Institute, 1975,83-93. 

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