Bond behaviors of BFRP bars in concrete using carbon fiber rib anchorage

•Bond behaviors of BFRP bars in concrete using carbon fiber rib anchorage are investigated.•An improved model for BFRP bars in concrete using additional rib anchorage is developed.•The prediction accuracy of proposed model are validated by a series of pull-out tests.•An additional rib with length-to-diameter ratio of 4.0 is suggested theoretically. The geometry of Fiber Reinforced Polymer (FRP) reinforcement considerably affects the load-carrying capacity of structural member. Utilization of additional rib anchorage is expected to be the more effective approach to enhance the bond strength between basalt-FRP (BFRP) bar and concrete. In this paper, A total of 20 tested specimens (including 16 anchored specimens and 4 reference specimens) are fabricated to carry out direct pull-out tests. The influences of concrete strength, anchorage length and anchorage diameter on the bond performance of BFRP bar-to-concrete interface are investigated. Finally, an improved constitutive model is proposed to describe the pull-out behaviors of BFRP bars embedded in concrete using carbon fiber rib anchorage. Results indicate that the bond strength between BFRP bar and concrete can be significantly enhanced by additional rib, increasing by 17.0% compared with reference specimen. The proposed model includes fewer undetermined parameters than existing model, and its prediction accuracy is verified by the relative error ranging between 0.02% and 5.48% in comparison with experimental result. The enhancement effects of additional rib are sensitive to anchorage configurations, an additional rib with length-to-diameter ratio of 4.0 is suggested theoretically in this paper.