Although architects and housing developers are 3D printing entire houses, their approaches cannot handle the requirements of large concrete structures. But 3D printing still has a role to play in architectural innovation by improving the use of formwork, the molds that hold concrete while it cures to form walls and other structural and aesthetic elements.
You most often see formwork composed of parallel plywood panels. Construction workers install reinforcing bars between the panels and pour in the concrete. Once the concrete cures, the formwork panels are removed.
Formwork must support heavy loads and retain its dimensions while the concrete cures. Ideally, the formwork should be durable and lightweight so it can be used again and lower the project’s costs.
Complex, curved concrete architectural shapes pose a challenge for the construction industry. Curved shapes require more complicated formwork made from steel or other materials. These take time to create and usually require highly skilled craftspeople to produce. This is why the cost of formwork can consume 40% to 60% of concrete construction budgets.
Recently, the 3D printing arm of chemical giant BASF partnered with German 3D printer manufacturer BigRep to offer a low-cost approach to 3D printing formwork.
“We developed a highly dimensionally stable, rigid formwork material, especially tailored to work seamlessly on the BigRep’s large-format 3D printers,” explained François Minec, the Managing Director of BASF 3D Printing Solutions.
The BigRep Pro line of industrial 3D printers has a 1 cubic meter print volume which lets construction companies print complex formwork without the need for intricate woodworking or metalworking. The companies claim they can produce custom formwork significantly faster than traditional approaches at a fraction of the cost.
“Our customers are seeing huge gains in terms of cost and speed,” Big Rep Managing Director Dr. Sven Thate said. “Our solutions are opening the doors to many new possibilities.”
To demonstrate these possibilities, the two companies created a spiral staircase for Switzerland’s construction innovation project NEST. The structure of each wing-shaped step is too complicated for traditional formwork. But using 3D design, the companies created a set of seven interlocking formwork facets that allow the casting of the fiber-reinforced concrete.
The design provides the same level of safety but consumes less than half of the concrete. “AM is enabling a new digital construction craft, driving the return of these advanced concrete casting techniques and closing the gap between expert craftsmanship and automated construction,” said BASF’s Jörg Petri.
Going beyond the economics and aesthetics, 3D-printed formwork promises environmental benefits. The making of cement accounts for 8% of annual industrial carbon dioxide emissions so anything that reduces cement consumption in concrete construction will help mitigate climate change. This is one of the reasons University of Michigan researcher Mania Aghaei Meibodi develops 3D printing solutions for making formwork.
Speaking at Autodesk University, Meibodi explained how 3D-printed formwork could reduce the concrete in an architectural slab by as much as 80% without sacrificing performance. Meibodi concludes, “The way we approach these technologies, if it’s with sustainability in mind, it can have a significant and positive impact… on the future of our own planet.”
