Presented by Viktor Mechtcherine, TU Dresden

The interest in digital concrete construction is rapidly increasing, as well as the expectations of this new, promising technology. The methods of digital fabrication with concrete are becoming ever more mature, so that several pilot projects have already been realized worldwide. However, there are still some hurdles to overcome before 3D-printing with concrete and other digital construction processes can be transferred to construction practice. One of the biggest challenges is the development of a practice-oriented approach for determining, adjusting, and testing the required material properties of fresh and hardening concrete. The difficulties in designing the rheological properties of fresh concrete result from different, sometimes conflicting requirements, which are determined by decisive technological steps – material conveying, shaping, depositing, and loading by subsequent concrete layers. To think through and to redefine are also relevant methods of material characterization. This article focuses on these issues in the context of what is by far the most commonly used digital manufacturing method, namely 3D-printing by layered extrusion deposition. However, the conceptual reasoning, theoretical foundations, and recommendations with regard to material testing can be analogously applied to other methods.