Electrochemical studies on the performance of conductive overlay material in cathodic protection of reinforced concrete

A type of conductive overlay material made of carbon fibre filled cementitious mortar has been proposed for cathodic protection of reinforced concrete structures. It possesses advantages over many other anode materials. To evaluate its potential application in practice, the mechanical, electrical, and electrochemical properties of the material have been investigated. The addition of carbon fibres enhances the strength and toughness of the mortar, as well as the electrical performance. Accelerated anodic polarisation tests and impedance measurements were employed to study the electrochemical behaviour. Both of the fibre content and pore solution composition influence the electrochemical property and, in particular, chloride ions have been shown to have a negative effect on the material. Results indicate that the optimum fibre content should be above but in the vicinity of the percolation threshold. The work confirms the possible utilization of this type of anode material in cathodic protection of reinforced concrete.