Some phenomena of macrocell corrosion.

The research aimed to investigate, macrocell corrosion phenomenon in concrete of which both the anode and cathode were in separate parts and subjected to various conditions and the effect of w/c ratio and cover depth over a cathode and Ac/Aa ratio on the corrosion during propagation at the anode. The polarity and current reversals were found and corrosion was presumed to be due primarily to oxygen attack. The restriction of the anode dissolution in concrete may outweight the other parameters around the cathode such as Ac/ Aa ratio. During propagation of the steel anode, the 0.40-0.70 w/c concretes over the cathode had greater effect on anode dissolution than the 20-50 mm cover depths. (A)