Assessment of Bond Strength of GFRP Bars Embedded in Fiber-Reinforced Cementitious Composites

In this study, the bond behavior of sand-coated glass fiber-reinforced polymer (GFRP) bars embedded in cementitious composite matrix reinforced with the recently developed basalt fiber (BF) pellets and steel fibers (SF) was evaluated. Several studies have attempted to introduce empirical models to estimate the bond strength of FRP-reinforced concrete (RC) specimens. In this study, the applicability of these models to predict the bond stress of straight and headed-end FRP bars embedded in normal concrete and fiber-reinforced concrete (FRC) was assessed. Test results of 413 pullout specimens, which were divided into four groups based on the type of the FRP bar or the cementitious matrix, were used to evaluate the available models. In addition, a proposed model to predict the bond performance of headed-end FRP bars with FRC pullout specimens was introduced. The model was calibrated against experiments conducted previously by the authors on FRP-FRC specimens. The model was capable of predicting the maximum bond strength with a mean experimental-to-predicted value of 1.09 and a standard deviation of 0.19.