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Fibre reinforced polymer (FRP) composite materials have been used as internal and external reinforcement for concrete structures. Flexural strengthening of concrete elements using near surface mounted (NSM)–FRP materials are a promising technology. This research is designed to investigate the behaviour of reinforced concrete beams strengthened in flexure with NSM–FRP bars. A total of 20 reinforced concrete beams were tested. Different parameters including internal steel reinforcement ratio, type of NSM–FRP bars, FRP bar diameter, bonded length, and groove size were investigated in this research. Test results showed that the use of NSM–FRP bars is effective in increasing the flexural capacity of concrete beams. In addition, a nonlinear 3D finite element (FE) analysis was used to numerically simulate the behaviour of the test beams. Comparisons between the FE predictions and experimental results showed very good agreement in terms of the load−deflection and load−strain relationships, ultimate capacities, and modes of failure for the tested beams.

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This paper reports the test results of 11 reinforced concrete beams strengthened with carbon fiber-reinforced polymer ͑CFRP͒ sheets and subjected to an aggressive environment. In this study, eight beams were cracked and repaired with CFRP sheets, while the remaining three beams were kept uncracked as a control. The beams were 150 mm wide by 250 mm deep by 2,400 mm long and lightly reinforced with a reinforcement ratio of 0.6%. Two types of carbon FRP products were considered: Sheets and strips. In terms of environmental exposure, three beams were kept at room temperature and eight beams were subjected up to 300 wetting and drying cycles with deicing chemicals ͑3% NaCl͒. Following the exposure, the beams were tested to failure in four-point bending. In addition, nondestructive tests were performed to determine the corrosion rate, as well as destructive tests to determine chloride diffusion and reinforcing bar mass loss. Based on the findings of the study, the long-term effectiveness of the CFRP strengthened reinforced concrete in aggressive corrosive environments was established.

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In addition to their high strength and light weight, fiber-reinforced polymer ͑FRP͒ composite reinforcing bars offer corrosion resistance, making them a promising alternative to traditional steel reinforcing bars in concrete bridge decks. FRP reinforcement has been used in several bridge decks recently constructed in North America. The Morristown Bridge, which is located in Vermont, United States, is a single span steel girder bridge with integral abutments spanning 43.90 m. The deck is a 230 mm thick concrete continuous slab over girders spaced at 2.36 m. The entire concrete deck slab was reinforced with glass FRP ͑GFRP͒ bars in two identical layers at the top and the bottom. The bridge is well instrumented at critical locations for internal temperature and strain data collection with fiber-optic sensors. The bridge was tested for service performance using standard truck loads. The construction procedure and field test results under actual service conditions revealed that GFRP rebar provides very good and promising performance.

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