Performance of FRCM Strengthened RC Beams Subject to Fatigue

Fabric reinforced cementitious matrix (FRCM) is a relatively new material system recently developed for the repair, retrofit, and rehabilitation of reinforced concrete (RC) and masonry structures.Concrete structures such as bridges experience high traffic volumes and varying vehicle axle weights causing repeated cyclic loading throughout their lifetime.Cyclic loading may cause damage to the structure, a phenomenon known as fatigue.Due to the novelty of FRCM technology, there is a lack of research regarding the long-term performance of FRCM systems for RC strengthening.This study aims to investigate experimentally the parameters that most influence the flexural fatigue performance of Polyparaphenylene benzobisoxazole (PBO) FRCM strengthened RC beams.For members subject to cyclic loading, a stress ratio vs. the number of cycles (S-N) curve is developed with the objective of defining the endurance limit of the strengthened beams.Failure mode and fatigue life of the beams during cyclic loading are investigated and discussed.