Abstract
I
Last month the 26th Climate Conference ended in Glasgow with a resolution, which, according to the UN Secretary-General, “reflects the interests, the contradictions, and the state of political will in the world today.” It is clear that climate change needs to be addressed from multiple perspectives, and technology and science in construction can play a central part. Research here is highly relevant: 30% of the material consumption of mankind is related to building materials. To improve the ecological footprint of buildings, we need to find ways to reduce the energy needed for construction and for operation.
Yet the construction industry has not substantially increased its productivity over the past decades. Contemporary construction sites very much resemble those from 100 years ago. The obvious lack of automation and digitalization demonstrates that the third industrial revolution has not entered the building sector yet.
Additive construction, the digital additive manufacturing of structures based on raw- or preprocessed materials, helps to address this challenge and is intensely researched.
No wonder, several months after our initial call for this special issue, we were overwhelmed by a large number of high-profile articles. Consequently, we decided to dedicate three special issues to additive construction beginning by focusing on the direct printing of concrete.
Traditional concrete construction encompasses various labor-intense manufacturing methods, which people seek to further simplify and automate. The idea of a formwork-free concrete construction was already realized in the 1930s, with “Machine for Building Walls,” invented by William E. Urschel, which would already build structures with layerwise extruded concrete—perhaps the first 3D printer ever. Almost 50 years later, Behrokh Koshnevic introduced the approach of contour crafting, extruding walls for the first time with construction robots. Today, the first extrusion processes have already entered the industry and the first buildings 3D have been printed.
But despite those pioneering works, there are still many open research questions, such as reinforcement strategies, the sustainability of material mixes, rheology control, optimized design solutions, and novel mechatronic printing setups.
For the first issue, we have a wonderful lineup of work that addresses these points, showing where the second generation of research in concrete printing can lead. This selection reflects well the interdisciplinary nature of the research joining material science, robotics, engineering, and architecture.
I would like to thank the editorial team around Skylar Tibbits for providing this special opportunity to start an intense scientific discourse around this topic, and especially Anastasia Hiller for the fantastic support in editing this journal. Last but not least, a big thank you goes out to all of the authors and reviewers for their great work that makes this special issue possible.
As always, your comments are welcome. For feedback and direct contributions to the journal, contact us at 3dp_eo@liebertpub.com.
We are witnessing another turning point of construction, and it is our chance to decide now its new direction. We need to learn to realize the full potential of 3D-printed concrete—toward a digital building culture and a more diverse and sustainable build environment.