Immersed cathodic protection design

Saudi Arabia) .......................................................... 82 6.2.4 CP criteria ............................................................................ 836.2.4.1 Protection potential ................................................ 84 6.2.4.2 Current density ....................................................... 87 6.2.4.3 Discussion ............................................................ 1006.2.5 CP design procedures and prerequisites ............................. 104 6.2.5.1 General ................................................................. 104 6.2.5.2 CP design prerequisite computations .................... 104References ............................................................................................. 1046.1 INTRODUCTIONMost of this work was conducted during the author's employment with the Materials and Corrosion department of Mott Macdonald in Altincham, United Kingdom. The author wishes to particularly thank Professor Paul Lambert and Dr Chris Atkins for their support and inputs. Reinforcing steel embedded in concrete, by definition, has a very low susceptibility to corrosion as the alkaline nature of the cement paste provides favourable conditions for the build-up and maintenance of a stable oxide film on the steel surface. However, the passive nature of reinforced concrete (RC) may be modified by the migration of aggressive species from the external environment to which the structure is exposed. The mechanisms of corrosion for atmospherically exposed RC structures are well documented, and cathodic protection (CP) has been proven to be a technically and economically effective method for stopping and preventing reinforcing steel corrosion. This particular application of CP has been employed for a large number of civil structures over the past 20-30 years and is now at a stage where the installation, design and performance criteria of such systems are largely mastered and adequately documented.