A study of the use of high functionality-based resin for bonding between CFRP and concrete under harsh environmental conditions

The application of carbon fibre reinforced polymer (CFRP) materials to strengthen and retrofit concrete structures requires appropriate bonding between the concrete members and CFRP composites. The experimental investigation reported in this work involved the modification of the adhesive used to bond CF fabric to concrete members, in order to improve CFRP/concrete bond performance under severe service conditions. The glass transition temperature, modulus and adhesive tensile strength of conventional bifunctional epoxy adhesives can be enhanced by their replacement with an epoxy resin monomer of a higher functionality, leading to a higher level of cross-linking. The interfacial bond strengths in the CFRP/concrete systems, the concrete/primer interface and the adhesive/primer interface were significantly improved when loaded CFRP/concrete samples were subjected to the combined effect of temperature and humidity for various exposures. This was true when either partly or fully replacing the conventional epoxy with the higher crosslink density material.