Cement-based adhesives for FRP–concrete bonding at elevated temperatures: a review of interface and AI insights

Cement-based adhesives (CBAs) have emerged as promising alternatives to epoxy resins for bonding fiber-reinforced polymer (FRP) systems to concrete. They are particularly attractive for applications requiring high-temperature resistance and compatibility with cementitious substrates. This review presents a structured and comparative assessment of current research on the mechanical performance, bond behavior, thermal resistance, and interface failure mechanisms of CBAs. Particular attention is given to nano-modified formulations containing graphene oxide (GO), graphene nanoplatelets (GNP), and nanosilica (NS). The role of the FRP–­adhesive and adhesive-concrete interface is critically examined in this review. These interfaces govern bond transfer, durability, and failure behavior in externally bonded and near-surface mounted (NSM) strengthening systems. Qualitative comparisons between CBAs and epoxy adhesives under elevated temperatures ranging from 200 °C to 600 °C are discussed to evaluate their relative performance and degradation characteristics. The review also examines recent applications of artificial intelligence (AI) for predicting FRP–concrete bond strength, highlighting the capabilities and limitations of existing machine-learning models. Finally, major knowledge gaps related to interface characterization, high-temperature durability, mix optimization, dataset quality, and AI-assisted modelling are identified. Future research directions are proposed to support the development and practical implementation of durable and thermally resilient CBA-based strengthening systems.