3D printing with soil: researchers develop alternative formwork technology

The use of soil as a building material could play a greater role in the construction industry in the future. Researchers at MIT have developed a method that allows lightly treated soil to be used as a mold for concrete structures. The technique relies on large-scale 3D printing to produce earth-based formwork that could replace conventional wooden molds. This could not only reduce costs, but also reduce the environmental impact of concrete buildings.

The process is based on processing locally available soil material, which is printed into precise molds. The resulting formwork is strong enough to hold the concrete and can be reused or recycled after curing. A special coating is applied to prevent water from escaping. This keeps the mold intact during the casting process.

“What we’ve demonstrated is that we can essentially take the ground we’re standing on, or waste soil from a construction site, and transform it into accurate, highly complex, and flexible formwork for customized concrete structures,” says Sandy Curth, a PhD student in MIT’s Department of Architecture who has helped spearhead the project.

“It has the potential for immediate impact and doesn’t require changing the nature of the construction industry,” says Curth, who doubles as director of the Programmable Mud Initiative.

Another advantage of this technology is the ability to realize complex geometries with little effort. 3D printing allows the shape to be adapted more precisely to the structural requirements, resulting in material savings of up to 50 percent.

“Concrete is a wonderful material when it is used thoughtfully and efficiently, which is inherently connected to how it is shaped,” Caitlin Mueller, an associate professor at MIT in the Department of Architecture and the Department of Civil and Environmental Engineering, says. “However, the minimal forms that emerge from optimization are at odds with conventional construction logics. It is very exciting to advance a technique that subverts this supposed tradeoff, showing that performance-driven complexity can be achieved with low carbon emissions and low cost.”

The researchers are working on further developing the method for practical use. In the future, construction companies could use large-format 3D printers directly on the construction site to produce earth-supported formwork on site. This could shorten the construction time and reduce dependence on conventional building materials.

Curth has written several articles on the method, most recently “EarthWorks: Zero waste 3D printed earthen formwork for shape-optimized, reinforced concrete construction”, published in the journal Construction and Building Materials. Curth wrote the paper with nine co-authors, including Natalie Pearl, Emily Wissemann, Tim Cousin, Latifa Alkhayat, Vincent Jackow, Keith Lee and Oliver Moldow, all MIT students, and Mohamed Ismail of the University of Virginia.

The process could represent a sustainable alternative, particularly in regions with limited access to industrial building materials. Whether the technology will be used on a large scale remains to be seen, but the research provides promising results for a more resource-efficient construction method.