Experimental prediction of material deformation in large-scale additive manufacturing of concrete

Additive manufacturing (AM) of cementitious material has become a popular subject over the last decade. The multidisciplinary nature of this topic has led researchers from multiple areas of expertise such as architecture, engineering, and materials science to collaborate to improve the technology, which does not permit yet to print mixtures with coarse aggregates, but is often referred to as AM of “concrete” or “concrete” printing. An important aspect of research in the area is finding a Portland cement-based mortar with adequate rheological, hardening and strength properties for printing architectural structures. In addition, the properties of fresh and hardened mortar and its deformation behavior affect the shape accuracy of the printed geometries and require designers to adjust the toolpaths and technology to account for issues in the printing. This paper is aimed at studying the deformation of a printed concrete mix, which previous studies have shown to be printable. It is focused on the effect of the number of layers, the number of beads and time on layer height and width. It proceeds through a series of experimental tests and it uses regression analysis to model material behavior. The resulting equations can be used in toolpath design to compensate for such deformation and have more accurate printed geometries subsequently. Future studies will be concerned with linking material properties with material deformation and use results to develop a more generic toolpath generator.