3D-Printable Materials Made with Industrial By-Products: Formulation, Fresh and Hardened Properties

Growing in the field of construction, 3D printing allows to build non-standard shapes and to optimise the use of resources. The development of printable materials requires good control of the fresh state of the material—between mixing and printing, a printable material has to evolve from fluid matter to be pumpable (extrudability) up to a matter supporting its own weight and those of superior layers (buildability). Our researches are focused on printable materials used in large printers, i.e., printers able to build structural pieces for buildings. As many pumps and printers can be used to achieve a wide range of parts, this paper presents a simple method to provide valuable guidance to users when a decision needs to be made about printable materials. In this context, our researches both try to maximise the use of industrial by-products to reduce the environmental cost of printed material and to propose tests easy to carry out in the field. Consequently, on the one hand, some printable materials that mainly include quarry washing fines have been developed and, on the other hand, Fall cone and Vicat tests have been used to determine the printability limit. By not focusing on a single formula, the novelty of this paper is to present to readers some parametric models, i.e., a methodology that can be used according to their own devices and applications. Based on a design of experiments, 20 formulas have been tested. Parameters that influence the quality of printing are highlighted. Mechanical tests results at hardened state and shrinkage measurements are also shown to demonstrate the ability of some formulas to be structural materials: compressive strengths at 28 days between 7.50 MPa and 18.40 MPa.