Evaluation of Printability and Flow Properties of 3D-Printed Earthen Mixes

The prevalence of 3D printing infrastructure components with in situ materials, such as soils, has been attributed to its reduced carbon footprint and optimized material usage. This method offers benefits such as reduced human labor, cost, and time, as well as increased geometric freedom. Nevertheless, there is a dearth of information regarding the optimal geotechnical properties and printing parameters necessary to print clay soils. Fundamental geotechnical characterization, including Atterberg limits, particle size distribution, activity, and moisture content, can offer valuable insights into printability. This investigation illustrates the performance of simulant clay soil mixtures composed of kaolinite and sand. In this study, kaolinite-sand mixtures were systematically evaluated through geotechnical characterization, along with tests for extrudability, buildability, yield stress, and hardened properties. Among the tested mixes, K30 (30% kaolinite, 70% sand) exhibited the highest buildability, sustaining 23 layers at 20.5% moisture with a yield stress of 5.80 ± 0.90 kPa, whereas K70 (70% kaolinite, 30% sand) achieved the highest 14-day unconfined compressive strength (405.42 kPa). The preliminary results of this study will assist in the selection of appropriate combinations and refine 3D soil printing by considering both clay-based material and printing characteristics.