Bond performance of NSM – CFRP laminates using different surface treatments and cementitious adhesives

Abstract

Carbon fiber reinforced polymer (CFRP) composites applied according to the near surface mounted (NSM) technique are nowadays regarded as an effective structural strengthening solution. However, despite the notable properties of polymeric adhesives, they present certain drawbacks such as the emission of toxic fumes and degradation of the mechanical properties after high temperature exposure. Thus, it is of great importance the research on alternative adhesives that guarantee similar target strengthening levels. Recent studies have been showing promising results with the use of cement based materials as adhesives due to their good ability for transferring stresses and compatibility to the substrate. However, further development of materials with improved performance are still required. The bonding properties in the case of carbon laminates applied according to the NSM strengthening technique still lag behind the desired requirements. This research explores the adoption of a pre-treatment procedure for carbon fibre laminates, aimed at increasing the bond strength between the cement based adhesive and the carbon fibre laminate applied according to the NSM strengthening technique. Pull-out tests results confirmed the effectiveness of the pretreatment technique for enhancing the bond strength