Performance of near surface mounted glass fiber reinforced polymer bars in concrete

Near surface mounted fiber reinforced polymer reinforcement has become very popular method in strengthening of reinforced concrete structures. The major problem that accompanied the near surface mounted technique is the bond between fiber-reinforced polymers and concrete that corresponds to the stress transfer from concrete into fiber-reinforced polymers. This article presents the test results of pullout tests of near surface mounted glass fiber reinforced polymer bars to investigate the effect of different parameters on the bond performance of this strengthening technique. The test parameters include: adhesive type, groove size, bonded length, environmental condition, and concrete strength. A total of 40 near surface mounted-fiber-reinforced polymer bars, installed in C-shaped concrete blocks, were constructed and tested to failure. Five types of cement and epoxy-based adhesives were used. Two groove sizes and three bonded lengths were also investigated. Normal and high strength concrete were also used. In addition, the effect of two harsh environmental conditions on the performance of the strengthening system was also investigated. The results are presented in terms of pullout loads, free end slip, and mode of failure.