Innovations in conductive mortars for durable corrosion protection of reinforced concrete structures: a comprehensive review

Abstract Corrosion of steel reinforcement within concrete structures can undermine their long‐term durability, spurring the development and implementation of cathodic protection (CP) systems to mitigate deterioration and extend service life. Impressed Current Cathodic Protection (ICCP) has demonstrated superior long-term performance and adaptability, particularly in aggressive marine environments. Despite its advantages, ICCP implementation is constrained by several challenges related to the acidification of backfill mortar, anode degradation, and loss of interfacial bonding between the mortar and substrate, which critically affect its service life and effectiveness. However, existing studies have predominantly focused on anode materials and system configurations, while the role and optimisation of anode backfill mortars remain comparatively underexplored. The apparent absence of specific guidelines concerning anode backfill mortar also creates uncertainty in design and implementation. Furthermore, a comprehensive understanding of how conductive mortar compositions influence the electrochemical performance and durability of ICCP systems is still lacking. These limitations demand a deeper investigation into the backfill mortar material properties. Therefore, this study first examines the integration of ionic and electronic conductive mortars in ICCP systems. Various additives, such as carbon-based materials, ion exchange resins, and layered double hydroxides, are incorporated to enhance ICCP performance by improving mechanical, conductivity, and durability properties. This review then further examines the practical applications of the mortars, highlighting how innovative design in conductive mortar formulations can substantially improve ICCP system efficiency. Future research directions are proposed, focusing on optimising additive compositions, incorporating advanced nano-structured materials, and leveraging innovative fabrication methods to enhance mortar performance. Furthermore, strategies to improve the durability and long-term reliability of ICCP systems are discussed. These insights emphasise the need for standardisation to support the continued advancement of ICCP technologies.