»Concrete, Glass, and Steel«

Interview: Thomas Masuch; Photos: ismd, TU Darmstadt, Anja Jahn, XtreeE / Lisa Ricciotti - 02/09/2018

Although additive manufacturing (AM) is still a recent development in the construction industry, it is already the focus of several research projects, has been used in some early applications, and has generated many creative and useful ideas. Three years ago, Professors Oliver Tessmann and Ulrich Knaack from Technische Universität Darmstadt launched the BE-AM (Build Environment Additive Manufacturing) Symposium with the intention of bringing together active players in the industry. As of this year, Formnext will be supporting the symposium as a sponsor and will be addressing this subject in the AM4U area. We spoke to the professors about current developments in AM in the construction industry, similarities between the construction industry and other industries in this regard, and future challenges.

Apart from the well-established 3D printed design models, AM is still a relatively new field in the construction industry. What developments are you focusing on as part of your research at TU Darmstadt?

KNAACK: At TU Darmstadt, numerous projects are under way to investigate the applications of additive technology using various materials. Our research focuses on subjects ranging from deposition welding with steel, to laser sintering, glass, and brick. We also have plans for paper-based 3D printing. In the context of additive manufacturing and Formnext, construc?tion represents a completely new area. While AM technologies are being applied in isolated cases, there is no overall structure. We want to change this. One of our goals in teaming up with Formnext is to increase our focus on these activities in the next few years.

TESSMANN: At the same time, we are also keeping an eye on processes and developments in architecture and wondering what new shapes and designs will be made possible by AM. Obviously, we don’t want to print anything that can already be created using other highly efficient systems. An example of this would be the sophisticated formwork systems that are already available for flat concrete walls. Instead, we are considering ways in which AM can help us reduce the amount of material we use and respond better to specific contexts. We can only achieve this if the technology is meaningfully incorporated into the overall process.

»In the construction industry, when mistakes happen, we do not necessarily call the entire process into question. Instead, we just get the crowbar.«

From other industries, we are already familiar with the use of 3D printing in the quest to achieve added value. Can you draw any parallels between these other industries and your own?

TESSMANN: On one hand, yes. On the other hand, however, the construction industry has its own distinctive features. In principle, every building is a one-off, even if it is constructed from industrially manufactured elements. Our processes are not yet optimized to the same extent as they are in the automobile industry, where thousands of identical products are manufactured. In our case, when mistakes happen, we do not necessarily call the entire process into question. Instead, we just get the crowbar. The second major difference between our industry and others is that there tends to be a clear separation between planning and production: the architect designs the product and the construction firm builds it. Deploying new technologies such as those used in AM, however, calls for a more integrated approach. Our deeply entrenched control construct will need to be broken open to allow this.

KNAACK: The quest for more added value is undoubtedly the main area of common ground shared by all industries that use AM technologies. The construction industry is subject to major cost pressure and is fairly conservative as a result. This is why we will not see widespread adoption of AM. It is more likely to be used to create individual intelligent building elements, particularly those with more complex geometries.

What tangible benefits can already be reaped in the construction industry today because of additive manufacturing?

TESSMANN: As we see it, two different approaches are possible. You can concentrate on producing architecture with complex features by allowing development to be driven by the creative process. In Darmstadt, however, we prefer to focus on small improvements, such as optimizing the topology of building components, asking ourselves questions such as »Is it possible to design steel support structures along load paths to make them lighter and more elegant?« Even the junctions between steel supports provide huge potential for improvements, if their topology can be optimized to make them lighter. When there are several hundred junctions, this can reduce the overall weight considerably. So, you see how seemingly small developments can have a significant impact on the big picture.

KNAACK: With some technologies, we are on the verge of a breakthrough. For example, we are now starting to use a relatively simple deposition welding technology for component testing, which we expect to put on the market in the next year or two. Some projects have already been implemented, such as a cycle bridge printed from concrete.

Using AM to give concrete a range of different material properties

Are there any developments that could fundamentally change the way we build? Is there a chance that building may even become less expensive?

KNAACK: Individual building components produced using 3D printing will become more compact and functionally integrated. Other components will become simpler. Overall, construction will become more efficient as a result. However, the price of buildings will not fall, since this is always determined by the value placed on them by society. However, the companies that use AM in construction will enjoy economic benefits. This economic aspect is also what encourages companies to collaborate with us on researching new applications and patents.

TESSMANN: Today, we insulate our houses with thick layers of insulating foam to fulfill energy conservation requirements. In the coming decades, this will generate a huge need for renovation as well as enormous amount of hazardous waste. There are ideas about returning to monolithic construction instead. Hopefully, we will soon be able to use AM to give concrete a range of different material properties. We will be able print concrete to be solid where it needs to provide support and porous where it needs to provide insulation, with a gradual transition in between. This will simplify the manufacturing process as well as subsequent recycling. At the same time, additive manufacturing can help us to create more customized, versatile, and context-specific buildings.

 

The success of any new technology also depends heavily on the users. What challenges can you see with this?

TESSMANN: We in the construction industry are a few years behind other industries. But things are starting to happen. What we still need are specific products as well as solutions in the areas of quality control and fire protection. If we can make progress here, the wheels will be set in motion.

KNAACK: We still have many more technical ideas, regarding the integration of materials, for example. Market penetration is a big challenge and we will also need rules. The whole process is likely to take another 20 to 25 years.

Mr. Tessmann and Mr. Knaack, thank you for taking the time to talk to us.

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