Experimental and FEM evaluation of the influence of interlayer bonding strength in 3D printed concrete members under compressive and flexural loadings

Abstract

The use of 3D concrete printing has remarkably increased in the building industry recently. However, the buildability and mechanical qualities of the printed concrete still depends on various influential elements. The purpose of this research was to investigate the impact of the interlayer bond on the anisotropic mechanical behavior of 3D printed concrete after 7 and 28 days of curing, under compressive and flexural loading of in and out of plane laminated surfaces while varying the concrete materials. The mechanical properties of the 3D printed concrete specimens were tested, and the results revealed that the compressive and flexural strengths were strongly dependent on the loading direction of the laminated surface. Analytical modeling of the specimens was performed using the LS-DYNA tool to further validate the experimental results. The effects of the interfacial friction bond and nozzle diameters on compressive and flexural strengths were investigated. Four alternative interlocking configurations, such as "I," "T,""S,"and "V" -shaped forms, were examined to increase strength by improving mechanical interlocking in the layers and the laminated surface, as well as interface responses.