Precast concrete sandwich one-way slabs under flexural loading

Abstract

The behavior of precast concrete sandwich panels consisting of two thin R/C layers (wythes) separated by an expanded polystyrene core is examined through experiments on prototype panels subjected to four-point bending, for different values of panel thickness and mesh size, with/without either shear-resistant ribs or conventional steel rebars (besides the wire mesh) in the bottom wythe. The test results indicate that all the panels behave as composite member until failure, and the panel behavior is similar to conventional R/C one-way slabs under flexural load. Due to the presence of wire mesh, cracking behavior in terms of number of cracks and crack spacing of concrete sandwich panels is similar to that of ferrocement cracking behavior. Volume ratio and specific surface of reinforcement affect the cracking behavior of concrete sandwich panels similar to that of ferrocement panels. The crack spacing based on predictive models for concrete slab reinforced with wire mesh agrees with the experimental results. Presence/absence of shear-resistant ribs and/or rebars in the bottom wythe significantly affects the flexural behavior of the panels. Presence of conventional rebars in the bottom wythe together with the wire mesh increases the ultimate flexural load capacity of the panels. The load-deflection response of the concrete sandwich panels exhibits trilinear behavior, and is similar to ferrocement behavior under flexural loading. Analytical study includes strength predictions based on conventional R/C beam analysis.