Researchers at the US Department of Energy’s Oak Ridge National Laboratory designed a novel polymer to bind and strengthen silica sand for binder jet additive manufacturing, a 3D-printing method used by industries for prototyping and part production. The printable polymer enables sand structures with intricate geometries and exceptional strength—and is also water soluble.

“To ensure accuracy in tooling parts, you need a material that does not change shape during the process, which is why silica sand has been promising,” said Dustin Gilmer, a University of Tennessee Bredesen Center student and the study’s lead author. “The challenge has been to overcome structural weakness in sand parts.”

The study, published in Nature Communications, featured a 3D-printed, 6.5 centimeters sand bridge that can hold 300 times its own weight, equivalent to the Brooklyn Bridge supporting 12 Empire State Buildings.

The binder jet printing process is cheaper and faster than other 3D-printing methods used by industry and makes it possible to create 3D structures from a variety of powdered materials, offering advantages in cost and scalability.

The concept stems from inkjet printing, but instead of using ink, the printer head jets out a liquid polymer to bind a powdered material, such as sand, building up a 3D design layer by layer. The binding polymer is what gives the printed sand its strength.

The full report can be found at ORNL.gov.