Study of the shear bond behavior of a hybrid fiber-reinforced concrete (HyFRC) composite slab

• Published in: Engineering structures Vol. 312; p. 118232
• Main Authors: Yu, Jing, Sneed, Lesley H., Zhai, Tianwen, Li, Yi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2024
• Subjects: Bond; Composite slab; Hybrid fiber-reinforced concrete (HyFRC); Numerical simulation; Prefabricated formwork; Composite slab; Numerical simulation; Prefabricated formwork; Hybrid fiber-reinforced concrete (HyFRC); Bond
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2024.118232

In this study, a new composite slab consisting of a prefabricated hybrid fiber-reinforced concrete (HyFRC) formwork and a cast-in-place ordinary concrete (OC) topping was proposed. The HyFRC was comprised of steel and PVA fibers. The compressive strength and bending strength of the HyFRC were 111.4 MPa and 15.6 MPa, respectively, and the toughness coefficient was 12.1 MPa. Seven full-scale composite slabs including six simply-supported slabs and one two-span continuous slab were tested under four-point bending to study the shear bond behavior. Three different contact surface conditions were considered for the simply supported slabs. Despite the different interface conditions, results showed that the interfacial bond strength between the HyFRC formwork and the OC topping was sufficient to achieve flexural failure. Numerical simulation was used to analyze the interfacial force transfer mechanism and was validated by the experimental data. The validated numerical model was used to study the influence of concrete topping depth and amount of reinforcement on the load-carrying capacity and longitudinal shear stress at the joint surface. The numerical results identified a critical condition of positive effect between reinforcement ratio and OC topping thickness. The peak load of a properly designed composite slab was almost two times that of the corresponding slab with ordinary concrete only, and the deformation capability was also larger. A procedure for calculating the flexural capacity of the composite slab was proposed. •Steel-PVA HyFRC was used as precast stay-in-place formwork for composite slabs.•Seven full-scale composite slabs were tested under four-point bending.•Numerical simulations of the composite slab were carried out.•Bonding properties between HyFRC formwork and OC topping were evaluated.