Enhancing bond performance of carbon fiber reinforced plastic bars in concrete structures: Insights and guidelines

This study examines the adhesion characteristics of fiber reinforced plastic (FRP) bars, specifically focusing on carbon fiber reinforced plastic (CFRP), within concrete matrices. Key findings underscore the significant influence of the concrete compressive strength values such as embedment length, surface treatment, and environmental conditions. Enhanced concrete compressive strength positively impacts interfacial strength, while longer embedment lengths result in weak interfaces within the composites. Surface treatment, particularly sand coating, is crucial when promoting higher interfacial bond strengths and adhesion. Comparisons with international design codes reveal discrepancies, with ACI 440.1R-15 closely matching test results. The study also highlights the advantages of using epoxy resins for FRP strengthening. In chloride environments, CFRP results in superior corrosion resistance when compared to basalt fiber reinforced polymer (BFRP) and glass fiber reinforced polymer (GFRP). However, interfacial bond strength retention decreases over prolonged exposure, exacerbated by wet-dry cycles and exposure to temperature fluctuations. Overall, this research provides valuable insights for selecting and designing robust concrete structures within FRP reinforcements, considering their advantages.