3D-Concrete-Printing by Selective Deposition (2018-10)¶

Interest in digital concrete construction is growing rapidly, and with it the expectations of this new, promising technology. The methods of digital production with concrete are becoming more and more mature, so that several pilot projects have already been realized worldwide. However, there are still a number of hurdles to overcome before 3D printing with concrete and other digital construction methods can be transferred to construction practice. One of the biggest challenges is the development of a practical procedure for determining, adjusting and testing the required material properties of fresh and hardening concrete. The difficulties in designing the rheological properties of fresh concrete arise from different, sometimes conflicting requirements, which are determined by key technological steps - material delivery, shaping, depositing and loading by subsequent concrete layers. Relevant methods of material characterization also need to be rethought and redefined. This article focuses on these issues in the context of what is by far the most frequently used digital production method, namely 3D printing by selective concrete placement. However, the thought processes, theoretical principles and recommendations regarding material testing can also be applied to other processes.