Effects of Bottom Layer and Insulation Thickness on Mechanical Behavior of Precast Concrete Sandwich Panels

Precast Concrete Sandwich Panels (PCSP) are lightweight structural elements that are composed of two thin outer concrete wythes and a middle insulation core. This article presents an experimental work that investigates the effect of the thicknesses of the bottom wythe and the insulation core on the flexural response of six PCSP specimens. Two parameters were adopted in the study, which are the lower wythe thickness and the core thickness. Three lower wythe thicknesses of 10, 15, and 20 mm, in addition to two core thicknesses of 50 and 100 mm, were considered. Therefore, six PCSPs were cast and tested under four-point loading. The load and corresponding deflection were simultaneously recorded using the data logger of the displacement-controlled testing machine. A constant self-compacting concrete mixture was used for all specimens. The test results showed a positive impact of bottom wythe thickness and insulation core thickness on the ultimate load capacity of the tested PCSPs, where percentage improvements reaching approximately 16% and 29% were recorded as the wythe thickness increased from 10 mm to 15 mm and 20 mm, respectively. However, a lesser percentage increases within a maximum of 12% were retained by increasing the core thickness from 50 to 100 mm. In addition, the 50 mm core PCSPs exhibited a more uniform flexural cracking pattern compared to those with a 100 mm core.