Characterisation of the Layer Pressing Strategy for Concrete 3D Printing

International audience; 3d printing of cementitious material by pressing layers during the extrusion is a strategy that requires a rather low initial yield stress so the material can deform without cracking. It allows to perfectly control the height of the layer and gives freedom in the orientation of the printing head and of the layer allowing for a wider range of printable geometry than the classic so-called "infinite brick" extrusion. This strategy has however some drawbacks as pressing the material on the previous layers may lead to a deformation of the sub-layers and even failure of the structure. In this work; we make a first step into understanding forces involved in such a process and measure their dependency on material fresh properties and printing parameters.