Bond Behavior of Basalt Fiber Reinforced Polymer Bars in Recycled Coarse Aggregate Concrete

This study is an experimental investigation of the bond stress-slip behavior of BFRP bars in recycled coarse aggregate concrete using the pull-out experiment. The experimental program contains twenty-three BFRP specimens and twelve specimens with GFRP bars. The pull-out test results of the BFRP and GFRP specimens in recycled coarse aggregate concrete are balanced to those of normal coarse aggregate concrete, which are used as a benchmark. In this study, the influence of major parameters on the BFRP bond performance are investigated: concrete strengths (30, 45, and 60 MPa), bar diameter (8, 10, and 12 mm), and bar bond length (5, 10, and 15d, where d is the diameter of the bar). The effect of the parameters considered is determined on the basis of the increase in the bond resistance. The test findings showed that the bond resistance of BFRP bars in recycled coarse aggregate concrete is highly comparable to that of normal aggregate concrete. In addition, the BFRP bar pull-out failure is not governing when a bar bond length of 10 or 15d, or high concrete strength of 45 or 60 MPa, is utilized. Theoretical equations from the literature that predict the bond resistance and bond stress-slip performance for FRP reinforced concrete are compared to the experimental results of this study. It is found that the equation described by Orangun and colleagues can accurately predict the bond resistance for BFRP bars in recycled coarse aggregate concrete with an average of 86% compared to the experimental results.