Use of a Conductive Recycled Mortar as an Anode in the Electrochemical Chloride Extraction in Reinforced Concrete

Abstract

This study advocates for the use of recycled materials, which are more environmentally sustainable as they decrease natural resource consumption. In this research, a mortar anode composed of recycled fine aggregate (RFA) from laboratory concrete blocks, carbon fiber (CF) waste from industrial processes, and graphite powder (GP) was developed, resulting in a conductive recycled mortar (CRM). The manufacturing process utilized Portland composite cement, RFA with a sand/cement ratio of 1.00, a water/cement ratio of 0.6, a GP/cement ratio of 0.50, CF comprising 0.5%, and carboxymethyl cellulose (CMC) comprising 0.4% by weight of cement. Chloride profiles indicated that the specimens with the CRM anode were effective, as the chlorides migrated into the mortar. For M0.5CF (2.81%) and M0.5CF0.5GP (3.72%) of free chlorides, the Ti–RuO₂ mesh did not expel the chlorides but rather accumulated them at 1 cm from the surface, resulting in a negative efficiency (− 20.02%). However, at 1 cm from the cathode, the efficiency levels were comparable across the anodes: Ti–RuO₂ mesh (84.54%), M0.5CF (84.76%), and M0.5CF0.5GP (81.11%), underscoring the potential of using a CRM anode for electrochemical chloride removal.