Flexural Behavior of Concrete Beams Reinforced with Ribbed Basalt-FRP Bars under Static Loads

Recently, basalt fiber–reinforced polymer (BFRP) reinforcement emerged as a new FRP type. Research is needed, however, to understand the behavior of BFRP bars in concrete members. This paper presents an experimental study aimed at investigating the flexural behavior and serviceability performance of concrete beams reinforced with ribbed BFRP bars. A total of eight concrete beams measuring 3,100 mm in $\mathrm{length}\times 200\mathrm{mm}$ in $\mathrm{width}\times 300\mathrm{mm}$ in depth were constructed and tested up to failure. Six beams were reinforced with 8-, 12-, and 16-mm BFRP bars with ribbed surfaces and two reference beams were reinforced with 10M and 15M steel bars. The beam specimens were designed in accordance with Canadian standards, and tested under four-point bending over a clear span of 2,700 mm until failure. The test results are presented and discussed in terms of cracking behavior, deflection, and failure modes. The test results yielded an average bond-dependent coefficient ($k_b$) of 0.83, which is lower than 1.0 recommended by Canadian standards for ribbed FRP bars. Moreover, comparing the test results to the design provisions showed that American Concrete Institute (ACI) Committee 440 Guide underestimated the deflections at service load for the beams reinforced with ribbed BFRP bars, while Canadian standards for design and construction of building structures with FRP yielded reasonable and conservative deflections.