Digital Fabrication with Local Earthen Materials: The Relevance of Process Robustness

The rapid development of climate change and the resulting EU climate targets require a significant reduction in CO₂ emissions . The usage of fully recyclable, locally sourced low-carbon materials, such as earthen materials, can play a key role in reducing CO₂ emissions. Currently, research in the field of additive manufacturing with earthen materials focuses on extrusion-based processes. However, with these new techniques, materials must be precisely tailored to the manufacturing process's requirements to achieve a functional material-process interaction. This results in the requirement for highly specialized materials, hindering the use of local earth resources with inherent varying compositions. As a traditional construction technique for earthen materials, rammed earth construction has been in use for thousands of years. Without adaptations to the ancient process to the current state of the art in industrialized countries, its use results in high construction costs. Therefore, research in advanced processing methods, including digital fabrication and automation approaches, could fully unlock the potential of local earthen construction and bridge the gap between traditional processes and the future demands of construction practices. The present research examines the challenges of sourcing and using local earth materials in a robust, automated, rammed earth manufacturing process. Therefore, investigations on the influence of process parameters such as layer height and impact energy on the material properties such as dry density and compressive strength using a range of raw materials are presented. The aim of this investigation is the identification of robustness criteria regarding the digitally controlled processing of local materials in the robotic rammed earth process on process and material level.