Mechanical response of textile-reinforced aerated concrete sandwich panels was investigated using instrumented three-point bending tests under quasi-static and low-velocity impact loads. Two types of core material were compared in the sandwich composite consisting of plain autoclaved aerated concrete (AAC) and fiber-reinforced aerated concrete (FRAC), and the stress skins were alkali-resistant glass (ARG) and textile reinforced concrete (TRC). The textile-reinforced layer promoted distributed cracking mechanisms and resulted in significant improvement in the flexural strength and ductility. Digital Image Correlation (DIC) was used to study the distributed cracking mechanism and obtain impact force-crack width response at different drop heights. A constitutive material model was also developed based on a multi-linear tension/compression strain hardening model for the stress-skin and an elastic, perfectly plastic compression model for the core. A detailed parametric study was used to address the effect of model parameters on the flexural response. The model was further applied to simulate the experimental flexural data from the static and impact tests on the plain aerated concrete and sandwich composite beams.

This paper evaluates the effect of layer height on the flexural response and crack propagation behavior of 3D-printed steel fiber-reinforced mortar beams. Beams printed with three different layer heights (5, 10, and 15 mm), with other dimensional and printing parameters maintained the same, were tested in four-point bending. The flexural strength increased with layer height in the range explored. Fiber lengths larger than the layer height introduced enhanced interlayer defects. Flexural load-deflection data were employed to determine a constitutive tensile stress-strain relationship. Digital image correlation (DIC) was used to measure the crack width along the depth, along with the strain profile. The relationships between stress and crack width were developed as a function of distance from the neutral axis, which demonstrated higher residual stress at a given crack width for the specimens with higher layer height. The study shows that a small amount of fibers in 3D-printed mixtures ensures better mechanical properties and that higher layer heights (within the limits used here) are beneficial in terms of mechanical behavior and speed of construction.