Electrical resistivity and microstructural properties of concrete materials in conditions of current flow

The concrete matrix has a significant contribution to the global performance of reinforced concrete. In conditions of current flow (as in the case of impressed current cathodic protection (ICCP)) the concrete bulk material undergoes changes in chemical composition, electrical properties and microstructure, thus influences the overall response of the reinforced concrete system. Aiming at optimization of the ICCP technique, a comparison study is carried out in this contribution between pulse and conventional ICCP in terms of bulk matrix (concrete) response to applied electrical current regimes. Ordinary Portland cement concrete blocks were cast, differing in experimental set-up and chloride concentrations. All specimens were subject to resistance monitoring and ion concentrations determination. The favourable effects of pulse cathodic protection current flow on the concrete matrix were additionally explained by microstructural analysis of the specimens. It is found out that physicochemical changes due to ion transport as well as electrical properties of the concrete matrix are attributed to the structural alterations of the pore space induced by the cathodic protection current.