Grading Material Properties in 3D Printed Concrete Structures

Abstract

Functionally graded materials (FGMs) describe composite materials with a gradual change in properties along one or several axes. A major advantage with this approach is the avoidance of discontinuities between different layers of material. 3D Printing offers the possibility to control the material composition and spatial placement along the printing process to create structures with graded properties. However, there are very few examples of the application of this approach to 3D concrete printing (3DCP). This paper presents a review of the current approaches of and methods to grade the material properties of a 3DCP structure, as well as a review of similar methods used in other 3D printing processes. Finally, the potential applicability of these principles into concrete are presented and discussed.

Spatially Graded Modeling: An Integrated Workflow For 3D Concrete Printing

“…Grading material properties has also been an interesting field of research in smaller-scale 3D printing (Zhang et al, 2019). While some attempts have been already tried using concrete (Ahmed et al, 2020;Craveiro et al, 2020), integrating functionally graded concrete by 3DCP remains a challenge (Hernández Vargas et al, 2022). From a design standpoint, this also presupposes the tools to develop designs featuring spatial gradations, a capability that is not available in traditional workflows.…”

Evaluating Clay Characteristics for Printable Geo-Materials: A Case Study of Clay–Sand Mixes

“…To reduce global Greenhouse Gas (GHG) emissions, new construction methods and materials are researched as an alternative to casting concrete. Extrusion-based 3D Construction Printing (3DCP) allows functional grading of material mixtures and largely consists of or integrates unfired soil/geo-materials [1][2][3]. The printable mixture design can be altered to enhance diverse properties, such as strength, insulation, CO2 saving capacity, the integration of waste sources and local materials, resistance against water, and their hygrothermal and acoustic properties, and it can also be used as nutrition for plants and animals [4][5][6][7].…”