The BioMatters team at the University of Michigan has developed a method to 3D-print "concrete structures" using sawdust.

The team at the Taubman College of Architecture and Urban Planning and Digital Architecture Research & Technology (DART) Laboratory is using sawdust created at the Fabrication Laboratory at Taubman.

“We have made a recyclable, all-natural biomaterial which is made out of sawdust. Other sawdust-based solutions are using other petroleum-based polymers—we use biopolymers which are completely decomposable,” said Muhammad Dayyem Khan, researcher at the DART laboratory. “And the biggest thing is it’s very easy to recycle and reuse.”

The method couples robotic 3D printing of the wood-based material with incremental set-on-demand concrete casting to create zero-waste freeform concrete structures. The 3D-printed wood formwork shapes the concrete during casting, and the concrete stabilizes the wood to prevent deformation. 

After the concrete cures, the formwork is removed and fully recycled by grinding and rehydrating the material with water, resulting in a nearly zero-waste formwork solution, according to the researchers.

“When the sawdust decomposes, it is producing fatty acids, lignin, which causes toxicity in water. Once it starts contaminating water, it has its effects on smaller wildlife, microbes, and a broad range of organisms. And with sawdust being extremely flammable, its potential contribution to wildfires is very high,” said DART director Mania Aghaei Meibodi.