Numerical modelling of bond behavior between rebar and high-strength fiber-reinforced cementitious composites (HSFRCC) for inter-module joint in modular construction

In modular construction, the optimization of joint design has always been a major challenge. The joint size is primarily governed by rebar-concrete bond strength, as tensile stress is transferred from one lapped bar to the other through the concrete substrate. The complex mechanism of rebar-concrete bond degradation is dependent on both the property of the bonded interface and the damage of surrounding concrete. By virtue of its exceptional mechanical performance that contributes to the enhancement in rebar bond property, high-strength fiber -reinforced cementitious composites (HSFRCC) are often adopted in precast construction to locally replace conventional concrete in the joint area. In a previous study, the authors explored the application of HSFRCC in modular construction and developed a novel inter-module joint design. Based on the mechanical properties of the materials and the explicit geometry of the bonded interface, a 3D finite element model was introduced and showed good agreement with pull-out test results. Building on the preceding works, this paper aims to further validate the numerical model and demonstrate its general applicability using HSFRCCs with different steel fiber content. With the validated model, the effects of rebar bond length, HSFRCC cover thickness, and thickness of steel plate confinement on the bond performance are investigated in parametric studies, which establishes the basis for formulating a rational design approach for the proposed joint method.