Static and Fatigue Performance of FRCM-Strengthened Concrete Beams

Fabric-reinforced cementitious matrix (FRCM) composites represent a new technique for strengthening concrete and masonry structures. Various studies confirm the efficiency of FRCM systems in terms of ultimate capacity gain, compatibility with the parent material, and viability in corrosive environments and under elevated temperatures. An appealing use of FRCM composites is to strengthen concrete bridges. Vehicular traffic imposes cycles of loading and unloading on the structure that can lead to fatigue failure, but the fatigue life of FRCM materials is yet to be investigated. This study examined fatigue performance of FRCM-strengthened reinforced concrete beams. Twelve concrete beams reinforced with carbon fabric were tested, including four benchmark beams subject to monotonic loading. The effects of fiber architecture and reinforcement ratio were accounted for by using two types of fabrics. Inspection of the fractured sections indicated that fatigue failure in the steel reinforcement was the predominant cause of failure. Analysis of applied stress range versus number of cycles to failure suggested that FRCM systems enhance fatigue life by controlling crack propagation in concrete.The project was made possible with the financial support received from the University Transportation Center RE-CAST and the Qatar National Research Fund (a member of Qatar Foundation) under NPRP Grant No. NPRP 7-1720-2-641