Hollow-core slabs with cast-in-place concrete toppings: A study of interfacial shear strength

August 30, 2013
Publication: PCI Journal v 58 n 3, p 124-141
Author(s): Ryan Mones BreƱa, Sergio F

Abstract: Precast concrete hollow-core slabs are often constructed with a cast-in-place concrete topping on site. Common construction practice includes applying cementitious grout between hollow-core units as a bonding agent. The cast-in-place concrete topping may contribute to the strength and stiffness of the hollow-core slabs if composite action is developed. The strength of the interface between the hollow-core units and the cast-in-place concrete topping largely depends on the surface condition of the slabs because it is not feasible to provide transverse reinforcement in these elements. The research presented in this paper primarily includes testing of two types of hollow-core units (dry mix and wet mix) to determine the interfacial shear strength between the units and the cast-in-place concrete toppings. Tests were conducted using push-off specimens designed to generate shear stresses at the interface. A parametric study is also conducted to identify the governing failure mode of topped hollow-core slabs as a function of span length.