Flexural behavior and serviceability performance of 24 full-scale concrete beams reinforced with carbon-, glass-, and aramid-fiber-reinforced-polymer (FRP) bars are investigated. The beams were 3,300 mm long with a rectangular cross section of 200 mm in width and 300 mm in depth. Sixteen beams were reinforced with carbon-FRP bars, four beams were reinforced with glass-FRP bars, two beams were reinforced with aramid-FRP bars, and two were reinforced with steel, serving as control specimens. Two types of FRP bars with different surface textures were considered: sand-coated bars and ribbed-deformed bars. The beams were tested to failure in four-point bending over a clear span of 2,750 mm. The test results are reported in terms of deflection, crack-width, strains in concrete and reinforcement, flexural capacity, and mode of failure. The experimental results were compared to the available design codes.

Fiber-reinforced polymer (FRP) sandwich systems as primary load-bearing elements are relatively new concepts in lightweight civil infrastructure. These systems offer a combination of light weight, high strength, thermal insulation for some types, and service-life benefits. Recent developments and applications have demonstrated that these composite systems have emerged as a cost-effective alternative, especially when each material component is appropriately designed. Still, some issues and challenges need to be addressed if FRP systems are to gain widespread use in civil infrastructure. This paper provides an overview of the state-of-the-art research, development, and applications of FRP sandwich systems. It also identifies the challenges and future opportunities for the broad use of these advanced systems in civil engineering and construction.

In addition to their high strength and light weight, fiber-reinforced polymer (FRP) 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 (GFRP) 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 an...

Current standards do not consider the diameter of glass fiber-reinforced polymer (GFRP) bars used as internal reinforcement in concrete structures to be a factor influencing bar durability. This paper investigates the effects of bar diameter on the physical and mechanical properties as well as the durability of GFRP reinforcing bars conditioned for three months at 60°C in an alkaline solution simulating a concrete environment. Five diameters (nominal diameters of 9.5, 12.7, 15.9, 19.1, and 25.4 mm) were considered; bar properties were assessed before and after conditioning. Microstructural analyses and measurement of physicochemical properties were also carried out. The results show that bar size had no significant effect on bar physical properties, except for water absorption. The smaller diameter bars had higher water absorption than the larger ones because of their higher surface area-to-volume ratios. In the case of the unconditioned bars, the tensile strength and modulus were not significantly affected by bar diameter, but there was a size effect for interlaminar shear strength and flexural strength. Conversely, the conditioning in the alkaline solution had a greater negative effect on the tensile strength of the larger bars than on the smaller ones. Scanning electron microscope (SEM) observations and Fourier transform infrared spectroscopy (FTIR) analysis revealed that the degradation remained at the surface of all the conditioned specimens. Nevertheless, there were only small variations between the physical and mechanical properties of the GFRP bars of different diameters. This indicates that the current provisions in standards that do not relate strength retention limit to bar size are acceptable.

Embedded through-section (ETS) technique is a recently developed method to increase the shear capacity of reinforced concrete (RC) using fiber-reinforced polymer (FRP) rods. The ETS method presents many advantages over existing methods, such as externally bonded FRP sheets (EB FRP) and near-surface mounted FRP rods (NSM FRP). Unlike EB and NSM methods where the FRP relies on the concrete cover of RC beams, in the ETS method, the FRP relies on the concrete core of the RC beam, which offers a greater confinement and hence improves bonding performance. Additionally, the ETS method requires less concrete preparation compared with EB and NSM methods. The objective of this paper is to present results of an experimental investigation that studies the effectiveness of the ETS method and compares the performance of the ETS method with both EB and NSM methods. In total, 12 tests are performed on 4,520-mm-long T-beams. The parameters investigated are as follows: (1) the effectiveness of the ETS method, compared with...