A new bonding agent for the Near-surface mounted Fibre-reinforced polymer strengthening system for concrete structures

Over the past few decades, the implementation of Near Surface Mounted (NSM) Fibre Reinforced Polymers (FRP) has become a promising strengthening method for improving the performance of concrete structures. Despite the common use of epoxy adhesives in NSM FRP systems, concerns have arisen due to their drawbacks, including the emission of toxic fumes and reduced mechanical strength when subjected to elevated temperatures and moisture. To address these issues, cement-based adhesives have been introduced as a substitute bonding agent with the goal of enhancing the performance of concrete structures in high-temperature settings and minimizing environmental and health hazards. In this paper, a new cement-based adhesive was introduced for the NSM FRP system for concrete structures. The efficiency of this adhesive was assessed through an experimental investigation involving pull-out testing using a single-lap shear test setup to study the bond behaviour of the NSM Carbon Fibre-Reinforced Polymer (CFRP) laminate for concrete structures. The results highlighted the potential of the developed cement-based adhesive as a promising alternative for strengthening systems requiring ductile bond performance, achieving approximately 65% of the maximum bond stress compared to epoxy adhesives in the NSM FRP system.