Traditional reinforcement cages are manufactured in a handicraft manner and do not use the full potential of the material, nor can they map from optimised geometries. The shown research is focused on robotically-manufactured, structurally-optimised reinforcement structures which are prefabricated and can be encased by concrete through SC3DP in a combined process. Based on the reinforcement concept of “reinforcement supports concrete,” the prefabricated cages support the concrete during application in a combined AM process. To demonstrate the huge potential of combined AM processes based on the SC3DP and WAAM techniques (for example, the manufacturing of individualized CPS), the so-called FLOWall is presented here. First, the form-finding process for the FLOWall concept based on fluid dynamic simulation is explained. For this, a three-step strategy is presented, which consists of (i) the 3D modelling of the element, (ii) the force-flow analysis, and (iii) the structural validation in a computational fluid dynamics software. From the finalized design, the printing phase is divided into two steps, one for the WAAM reinforcement and one for the SC3DP wall. The final result provides a good example of efficient integration of two different printing techniques to create a new generation of freeform coastline protection structures.

The construction industry is facing a dual challenge: an increasing demand for new buildings on the one hand and the urgent need to drastically reduce emissions and waste on the other. One promising field of research to face these challenges comprises additive manufacturing (AM) technologies. Through these advanced methods, digital workflows between design and fabrication can be implemented to optimise the form and structure, unlocking new architectural freedom while ensuring sustainability and efficiency. However, to drive this transformation in construction, the new technologies must be investigated in large-scale applications. One of these fast-emerging AM techniques is Shotcrete 3D Printing (SC3DP). The present research documents the 1:1 scale manufacturing process, from digital to real, of a building section utilising SC3DP. A workflow and production steps, spanning from design over manufacturing to assembly, are introduced. The architectural design, reinforced by computational methods, was iteratively refined to adapt to manufacturing constraints. The paper also emphasises the importance of a digital twin in ensuring seamless data integration and real-time adjustments during construction. By incorporating reinforcement techniques such as short rebar insertion and robotic fibre winding, this study demonstrates the structural capabilities achievable with SC3DP. In summary, the implementation of comprehensive digital workflows utilising computational design, automated data acquisition and data flow, as well as robotic fabrication is presented to demonstrate the potential of AM methods in construction. Furthermore, this paper provides a perspective on potential future research paths and opportunities inherent in leveraging the innovative SC3DP technique.

The current state of the art for additive manufacturing often utilises horizontal layer printing approaches for a variety of materials and applications. However, it imposes restrictions on the integration of utilities, mounting fixtures, installations, and reinforcement. Particularly the integration of reinforcement into 3D concrete printing still faces many challenges. It is currently restricted by the nozzle to strand distance, the lack of bond quality, automation, and geometric limitations of the respective 3D concrete printing techniques. The following research presents a case study on additively manufactured concrete construction elements utilising the Shotcrete 3D Printing (SC3DP) technique, focusing on interlayer- and short rebar reinforcement. To demonstrate the potential benefits for an automated reinforcement integration and to uncover further challenges and research questions, a wall segment was produced using a unique combination of Interlayer Reinforcement (ILR) and Short Rebar Insertion (SRI). By incorporating these methods, it was possible to generate three-dimensional continuous reinforcement structures within the wall. The innovative approach showcased takes full advantage of the SC3DP technique, enabling the integration of reinforcement during the printing process itself, thus utilising the geometric freedom, the fast build up rate and the kinetic energy during application. This eliminates the need for premanufactured reinforcement structures, enabling a more efficient and flexible manufacturing process. Furthermore, the discussion includes the potential for surface finishing and attainment of geometrical accuracy through the direct integration of reinforcement. An outlook is given as future construction elements can be produced structurally reinforced without formwork and with a high degree of geometric freedom.