In an innovative breakthrough, MIT researchers have developed a method to use lightly treated mud, including soil from a construction site, as formwork molds for concrete. This technique, which involves 3D printing, could significantly lower construction costs and reduce environmental impact.

“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 at MIT and director of the Programmable Mud Initiative.

Traditionally, builders construct temporary wooden molds for concrete, which are expensive and time-intensive. The new "EarthWorks" method uses soil reinforced with straw and coated with a wax-like material to create durable and reusable molds. “We found a way to make formwork that is infinitely recyclable. It’s just dirt,” Curth explains.

This approach not only reduces costs but also cuts carbon emissions. Concrete accounts for roughly 8% of global carbon emissions, and optimizing its shape using the EarthWorks technique can reduce emissions by more than 50%. “The EarthWorks technique brings these complex, optimized structures much closer to built reality,” says Caitlin Mueller, associate professor at MIT.

The innovation also allows for greater flexibility in construction design, enabling architects to create unique shapes more efficiently. “What’s cool here is we’re able to make shape-optimized building elements for the same amount of time and energy it would take to make rectilinear building elements,” Curth adds.

The EarthWorks project represents a collaborative effort involving multiple MIT researchers and has garnered support from the Sidara Urban Research Seed Fund. Curth hopes to bring this method to the construction industry through his firm, FORMA Systems, envisioning a future where mud-based construction becomes a global standard.

“People have built with earth for as long as we’ve had buildings,” Curth says. “This approach decouples cost from complexity. I guarantee you we can start to make higher-performance buildings for less money.”

The technique could eventually enable entire structures, such as two-story residential buildings, to be made entirely from soil, offering an inexpensive and sustainable alternative to traditional construction methods.