Bond-slip constitutive model and numerical analysis for rebar embedded in steel-polyethylene hybrid fiber-reinforced cementitious composites

The synergetic effect between the deformed rebar and steel-polyethylene hybrid fiber-reinforced cementitious composites (HECC) plays a critical role in assuring the performance of reinforced HECC structures. In this paper, the bond behavior between the deformed rebar and HECC was studied under direct pullout tests. Based on the experimental results, a simplified bond-slip constitutive model for the rebar embedded in HECC was proposed by modifying the existing bond-slip constitutive model, which is shown to be able to accurately describe the bond slip relationship between the rebar and HECC and serve as the basis for reinforced HECC structural design. According to the distribution of bond stresses along the anchorage length, an anchorage position function was developed; and then a refined bond-slip constitutive model considering the anchorage position function was established. Furthermore, a finite element analysis (FEA) model, considering the nonlinear bond behavior between the rebar and HECC was built through the use of nonlinear spring elements based on the bond stiffness obtained from the proposed refined bond-slip constitutive model. The accuracy of the FEA model in predicting the bond-slip behavior between the rebar and HECC was also verified.