Optimisation of Earth-Based Mixtures in Terms of 3D-Printability and Mechanical Properties: Feasibility Study

This short paper presents the results of the feasibility study on the production and application of 16 different raw-earth mixtures in 3D-earth-printing technology. Mixtures were composed of raw earth with different additional nature-based ingredients such as lime, water glass, oven ash, different natural fibres etc. No cement was added to the mixtures. Our primary goal was to show how the mix design influences the 3D-printing ability (for additive manufacturing, layer-by-layer) in small-scale and large-scale printing test. We also analyzed shrinkage as well as compressive and bending strength in the hardened state. In the first part of the paper, mix compositions, testing methods and behavior in the fresh state are shown. Special emphasis is put on pumpability and stability in small- and large-scale printing tests. Subsequently, important properties in the hardening state (shrinkage) and in the hardened state (compressive and bending strength) are presented. Finally, discussion about results and further prospects regarding possible applications for sustainable structures are presented.