USE OF CFRP COMPOSITES IN REINFORCED CONCRETE STRUCTURES

Carbon Fiber Reinforced Polymer (CFRP) composites have become a high-performance material for strengthening and retrofitting reinforced concrete (RC) structures. This review provides a broad overview of CFRP applications in RC members, focusing on the mechanical properties of CFRP, common strengthening methods, failure modes, and advantages over traditional steel reinforcement. The mechanical properties of CFRP—such as high tensile strength-to-weight ratio, corrosion resistance, and good fatigue performance—are highlighted, along with its limitations including brittleness, cost, and fire sensitivity. Application methods for CFRP in structural strengthening are discussed, emphasizing externally bonded reinforcement (EBR) and near-surface mounted (NSM) techniques. Typical failure modes of CFRP-strengthened RC beams (e.g., CFRP rupture, debonding at the FRP–concrete interface, and concrete crushing in compression) are reviewed based on literature and experimental studies. As an example, an experimental dataset from Al-Khafaji and Salim (2020) is presented, showing significant improvements in flexural capacity (up to 90% increase in ultimate load) of continuous T-beams strengthened with various CFRP configurations. The discussion synthesizes findings from multiple studies, comparing the effectiveness of different CFRP strengthening strategies and the resulting structural behavior (such as strength gains, stiffness changes, and ductility). Finally, the advantages of CFRP retrofitting over traditional steel plate bonding or section enlargement methods are summarized, along with considerations like design code provisions and long-term performance. This review demonstrates that CFRP composites provide an effective solution for extending the service life and capacity of existing concrete structures, as long as their application is properly designed to prevent premature failure.