Throwing power of localised anodes for the cathodic protection of slender carbonated concrete elements in atmospheric conditions

Advantages of cathodic protection, such as the possibility of preserving non-protective concrete and of reducing the invasiveness of the repair intervention, could be further improved by using small localised anodes, that do not affect the shape and surface of the element. However, the effectiveness of localised anodes needs to be verified, in particular in relation to current distribution issues that may be critical in slender and carbonated elements exposed to atmospheric conditions. This paper presents experimental results obtained on a real-size specimen aimed at investigating the possibility of using localised anodes (either with impressed current or galvanic) to protect steel in slender carbonated elements.

► Impressed current and galvanic localised anodes were applied to a real-size element.
► Potential distribution was measured to define the height of protection.
► For impressed current anode, height of protection increased with applied current.
► Galvanic anode gave results consistent with those of impressed current.
► Few localised anodes may be effective in protecting carbonated slender elements.