A collaborative team from the University of Maine and the Department of Energy’s Oak Ridge National Laboratory (ORNL) in the US has achieved a significant breakthrough in sustainable construction. They have created a recyclable, single-piece floor panel that is strong enough to potentially replace traditional materials like steel.

This innovative project is part of the Sustainable Materials and Manufacturing Alliance for Renewable Technologies (SM2ART) initiative. Notably, the team previously developed BioHome3D, the first home in the US made entirely from biologically based materials.

The newly designed SM2ART N-floor cassette panel aims to transform how apartment and condominium buildings are constructed by replacing conventional steel-and-concrete surface assemblies. This technology opens the door to creating environment-friendly, strong, biologically based components, which could enhance the sustainability of multistorey buildings.

Key advances

Katie Copenhaver, a researcher at ORNL, emphasised the advancement made with this project. “Our first attempt to create a robust building floor panel using green resources significantly boosts the potential for integrating organic materials in modular residential buildings,” she stated.

“Using bio-based, large-scale 3D printing, we simplified the assembly from 31 parts and three materials to a single-material floor panel that is both ecologically sound and as strong as traditional steel.”

The strength of the SM2ART floor cassette comes from its unique blend of polylactic acid (PLA) and wood flour, derived from corn residue and lumber processing waste.

Scott Tomlinson, a structural engineer at the University of Maine’s Advanced Structures and Composites Center, highlighted the advantages of this blend. “It’s an excellent material for producing recyclable, large-format additively manufactured components,” he noted.

“This single-piece floor assembly is stiffer and offers a superior walking experience compared to traditional steel-concrete setups.”

Researchers utilised a large-scale 3D printer to construct the floor panel by precisely layering the PLA and wood flour mixture. This method allows the printer to operate autonomously and continuously, producing the N-floor cassette in about 30 hours, yielding a labour savings of roughly 33% compared to manual assembly of a steel floor.

Traditional steel frame construction incurs significant costs due to the manual labour involved in cutting channels for electrical and plumbing systems. “3D printing can eliminate this by integrating cutouts directly into the floor cassette design,” Copenhaver explained. “Human labour is only required for installing sound-proofing and the chosen floor covering.”

Fully recyclable

Another significant benefit of the SM2ART N-floor cassette is its full recyclability. Unlike typical construction materials that end up in landfills, the PLA used in these panels can be repurposed into new products after a building’s demolition, promoting a circular economy.

The concept for this project was proposed by SHoP Architects, a design firm based in New York City. Copenhaver remarked: “They challenged us to mass-produce floor panels using greener materials and additive manufacturing. Experimentation and innovation are core to ORNL’s mission, and we successfully optimised the production process to ensure quality and consistency.”

While the N-floor project is still in its early stages, future research will explore enhancements such as flame retardants, sustainable insulation options, and improved production techniques.

Tomlinson noted, “Our next steps focus on increasing efficiency and cost-effectiveness while adding functionality. This technology has great potential for the future of sustainable building practices.”

Current research on the SM2ART N-floor cassette is being conducted at the Manufacturing Demonstration Facility at ORNL, with design and printing activities happening at the University of Maine’s Advanced Structures and Composites Center. 

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