Orientation Dependency of 3D printed SHCC at increasing length scale

Abstract

In the first part of this study, the inclination-dependent effects on a single fibre embedded in 3D printable strain hardening cementitious composite are studied. Two distinct failure modes (i.e., slipping rupture and complete pull-out) were found in the experimental results. Based on these failure modes two separate slip-hardening factors have been determined and analysed with an analytical fibre pull-out model. The second part of the study focused on the influence of multiple fibres with varying inclination angles on single- and multiple-cracking specimens. These tests have been performed for specimens that were casted and printed, to analyse the effect on ductility due to the extrusion process. Three orthogonal directions were examined within the printed specimens during testing. The amount of energy dissipated during the crack opening is strongly orientation-dependent for 3DP-SHCC and does not significantly increase in the main printing direction compared to casted SHCC. Furthermore, the orientation-dependent ductility is evaluated in bending with the use of a 4PB test. Allowing multiple layers of fibre-reinforced material to become active at the same time. The strain hardening effect found in a single crack is amplified by the material’s capability to develop multiple cracks, ultimately leading to a significant increase in its impact on engineering applications related to bending.