Flexural behaviour of concrete beams reinforced with steel-FRP composite bars

Abstract

Corrosion of steel reinforcement affects the durability of concrete structures. This led researchers to look forward to alternatives for steel reinforcement. One of these alternatives is Fiber Reinforced Polymer (FRP) reinforcement, which has high tensile strength as well as excellent corrosion resistance. However, the use of FRP reinforcement always comes at the expense of ductility. Thus, Steel Fiber Composite Bars (SFCBs), which consist of a steel core and FRP protective coating, could be a suitable alternative to conventional steel/FRP reinforcement. In the current work, fourteen concrete beams were tested to investigate the flexural performance of concrete beams reinforced with manually produced SFCBs. All beams had similar dimensions of 200 mm width, 300 mm height, and a clear span of 1700 mm. The main parameters were the reinforcement type (steel/SFCB) and the concrete compressive strength (30, 40, and 50 MPa). The experimental results were presented in terms of; crack pattern, failure modes, cracking load, ultimate load, load-crack width response, load-deflection curves, and the reinforcing bars' strain curves. The test results showed that, at the same load level, using SFCBs as tensile reinforcement increased the beams' mid-span deflection and crack width compared with those reinforced with steel bars. Finally, an analytical study was performed to predict the ultimate loads, maximum crack width and maximum deflection at service load of SFCBs reinforced beams. The results from the analytical study were very close to the test results, validating the accuracy of the suggested formulas for usage in practice.