Performance of reinforced concrete beams strengthened with NSM CFRP composites for flexure using cement-based adhesives

Numerous studies have been conducted on flexural strengthening using epoxy adhesive for both externally bonded and Near-Surface Mounted carbon fibre reinforced polymer (NSM CFRP) composites. Substitution of epoxy with cementitious bonding material for flexural retrofitting of concrete structures has great potential to overcome the drawbacks and disadvantages associated with the use of epoxy adhesive. However, limited studies have been conducted for the use of cementitious adhesives for near-surface mounted strengthening system due to the special physical properties required for this technique. A modified cement-based adhesive has been developed for this purpose and comparable bond properties have been achieved. In this paper, an experimental program has been conducted to investigate the flexural behaviour of reinforced concrete beams retrofitted with NSM CFRP textile and laminate using modified cement-based adhesive. Numerical analysis using finite element has been used to evaluate the experimental results and parametric study for future design requirements. The findings showed significant and excellent increase in flexural strength, achieving almost same that results gained from epoxy adhesives and comparable finite element results.