Development of Conductive Mortar for Efficient Sacrificial Anode Cathodic Protection of Reinforced Concrete Structures—Part 2: Four-Year Performance Evaluation in Bridges

Abstract

This study explores the efficacy of a sacrificial anode cathodic protection (SACP) system with an activated carbon-based conductive mortar in bridge structures. In the previous Part 1 study, various admixtures were compared to identify a conductive mortar for enhancing the performance of the SACP system, assessed through electrical conductivity, resistivity, cathodic protection (CP) potential and current, and 4 h depolarization potential. Part 2 extends the investigation by applying the developed conductive mortar containing activated carbon to an SACP system on an actual bridge structure in which corrosion has already been initiated. Before CP installation, the physical properties of the conductive mortar were evaluated to satisfy the standard requirements for concrete structure maintenance. Subsequently, zinc mesh and bulk anodes were installed on the bridge pier, followed by the application of a conductive mortar with an admixture ratio of 5%. Over a four-year period, performance was measured through regular 4 h depolarization potential checks and visual inspections. The SACP system with the conductive mortar demonstrated superior CP performance compared to the general mortar, confirming the effectiveness of the developed conductive mortar. Visual inspection after four years confirmed the workability of the SACP system with conductive mortar.