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22 TABLE 2 and decks. Arc sprayed zinc comes in a distant second and USE OF CATHODIC PROTECTION also has been used on all bridge components, most often on ON VARIOUS BRIDGE COMPONENTS columns. The third contender is the arc sprayed aluminum Cathodic Protection No. of zincindium alloy and it also has been used on all bridge Installed on Bridge Respondents components. The zinc foil has been used on all components Components Deck 22 other than the struts and the footers. Superstructure 9 Caps 12 INTERNATIONAL USE OF CATHODIC PROTECTION Columns 19 Piles 8 Around 1984, European countries started to recognize the magnitude of the corrosion problem and, in 1985, the United Footers 4 Kingdom began an evaluation of the technology. Since then, Note: Table based on results of Question 21 of the survey. 2.15 million square feet of concrete surface has been pro- tected using various different types of cathodic protection systems. In Northern Europe, Denmark leads with more than 60 installations, with 8 to 10 installations added each year. to have been used on all bridge components by the greatest At present, the majority of the cathodic protection systems number of agencies. Arc sprayed zinc was reported as the sec- are being installed on swimming pools. Two manufacturers ond most used system. However, more applications of it are of remote monitoring and control systems for cathodic pro- found to be on caps and columns. The conductive paint has tection are located in Denmark, and one of them is also been used on all bridge components, with the exception of an anode supplier. Conductive coating systems are a norm the bridge deck and is the third most used system. in Norway and four bridge structures have been protected in the last 8 years. In Norway, the installation activity is The point zinc anodes (hockey pucks) lead the galvanic more focused on parking structures. Several tunnels and cathodic protection category by a wide margin and have been bridges have received cathodic protection in Switzerland used on all bridge components, most often on columns, caps, and the area protected in 1997 was estimated to be more TABLE 3 TYPES OF CATHODIC PROTECTION SYSTEMS USED BY RESPONDENTS Impressed Current Cathodic Protection Galvanic Cathodic Protection Jackets with Expanded Zinc Mesh Hockey Puck Zinc Anodes Arc Sprayed Titanium Conductive Polymer Arc Sprayed Alloys Arc Sprayed Alloys Arc Sprayed Zinc Arc Sprayed Zinc Zinc Foil Anodes Zinc Bulk Anode Conductive Paint Titanium Ribbon Ceramic Anode Titanium Mesh Ferex Anode Other Other Bridge Elements Bridge Decks 2 1 0 0 0 3 5 12 5 2 1 1 7 1 0 1 3 Beams, Girders, and Diaphragms 1 1 0 1 0 0 1 2 0 0 4 3 4 3 1 1 0 Caps 5 0 1 3 0 0 1 3 0 0 4 4 9 3 0 0 0 Columns 5 0 1 3 0 1 1 4 0 0 8 5 12 4 2 2 0 Piles 0 0 0 1 0 0 0 1 1 1 2 2 2 2 3 7 1 Struts 1 0 0 2 0 0 1 1 1 0 3 1 3 0 0 0 0 Footers 1 0 0 2 0 1 1 1 1 0 2 1 1 0 0 2 1 Note: Table based on results of Question 22 of the survey.

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23 than 107,000 square feet. Italy has installed cathodic protec- and wharves have received cathodic protection. South Korea, tion on 1.6 million square feet of deck surface of new bridges Singapore, and Japan also have a few installations. China containing prestressing elements. The British Standard Insti- began using cathodic protection on structures built for the tute has developed a standard for the use of cathodic protec- 2008 Olympics. Some activity is also underway in India. tion technology in Europe. One of the largest reinforced concrete cathodic protec- As early as 1996, Australia and Hong Kong started to tion systems to be installed in the Middle East is the titanium use cathodic protection. In Australia, a number of bridges, mesh anode system installed in Yanubu, Saudi Arabia, in wharves, and other structures, including the supports of the 1987. Since then, many new and old structures in the Middle Sydney Opera House, have received cathodic protection. East have received cathodic protection. The total protected With Hong Kong's large coastal exposure, several bridges area is estimated to be in excess of 5.4 million square feet.