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Concrete is an inexpensive, naturally sustainable building material, and – after water – it is the most widely used substance in the world. However, the machines required to 3D print a building are expensive (anywhere between £135,000 and £750,000) which is a major reason for the slow uptake.
But there are several benefits of using a concrete 3D printer rather than traditional, manual methods. Namely, it is faster, cheaper, safer and more efficient. Concrete 3D printers not only produce minimal waste but also reduce the number of staff on site as well as the length of supply chains. Additionally, construction can be completed to a higher degree of resilience and geometric complexity.
3D-printed office space
As the technology is based on extrusion, concrete 3D printers work similarly to standard FDM 3D printers. First, a 3D model is created using software which is then sliced and translated into G-code. This G-code then guides the print head which deposits material in layers pumped from a cement mixer.
German construction manufacturer Peri and Austrian contractor Strabag have created Europe’s largest 3D-printed office space and Austria’s first 3D-printed building. The 125m2 building was printed in 45 hours at Strabag’s asphalt mixing plant in Hausleiten using a dry mortar, called Tector Print, supplied by Lafarge, which was applied using the BOD2 gantry printer made by Danish firm Cobod. Its print head moves over three axes on a permanently installed metal frame, so the printer can move to any position within the construction and only needs to be calibrated once.
Berthold Kren, Lafarge Austria’s chief executive, said: “Printed buildings will help to establish a new, digitally and environmentally advanced language for concrete. The intelligent material is convincing in its application and provides a high degree of architectural freedom in design. It allows us to build more with less.”
Klemens Haselsteiner, Strabag board member responsible for digitalisation and innovation, added: “3D printing brings an important innovation impulse for the industry and is an exciting addition to other construction methods.
“With this practical test, we want to further develop 3D construction printing together with our partners Peri and Lafarge. In Hausleiten, we were able to achieve important findings for future use during the joint planning.”
Growing portfolio
The Hausleiten office is the fifth project successfully completed by Peri in the past year. The company has also built the first market-ready 3D-printed house in Germany (in Beckum); a three-floor apartment building in Wallenhausen, Germany, which is said to be the largest printed building in Europe; a 3D-printed house in Tempe, Arizona; and an apartment building extension in Lindau, Germany. These are not research projects, but buildings that have gone through all the necessary building code approval processes and are rented out and occupied.
The impact of additive manufacturing in the construction industry is starting to be seen in projects around the world. These include Texas-based Icon and New Story creating the first permitted 3D-printed house in Austin in 2018. US start-up Mighty Buildings recently raised $30m to scale up its production line at its Oakland factory, enabling it to fully 3D print 33m2 units, while US-based concrete specialists Quikrete and Contour Crafting collaborated to develop a proprietary concrete for use in the building of low-income housing and disaster relief facilities in Los Angeles.
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.