Turning Scrap Wood into Strong, Sustainable Materials for Re-use

According to the U.S. Army Corps of Engineers, more than 80% of solid waste produced on Department of Defense (DoD) forward operating bases consists of scrap wood, cardboard, and paper.¹ This equates to almost 13 pounds of waste per soldier per day, often disposed of in landfills or buried on-site. DARPA’s new Waste Upcycling for Defense (WUD) program aims to research and develop an end-to-end process for turning scrap wood and other cellulosic waste streams such as cardboard and paper into lightweight, strong, and sustainable materials for re-use in multiple DoD environments. If successful, WUD will help mitigate the DoD waste disposal burden, alleviate supply chain logistics, and reduce the overall carbon footprint associated with DoD construction and defense, while simultaneously providing a pathway for sustainable building materials.

Recent studies² have shown that through chemical treatment and pressing, wood can be densified with enhanced mechanical properties. The densified wood allows for unique modes of energy dispersion, enhanced durability, and greater strength-to-weight than steel. These materials have thus far been developed in small batches with virgin lumber, but early results indicate that wood chips and scrap lumber may be used as the source for creating densified wood-like products. Biological processes have also been recently investigated that may replace or supplement the harsh chemical processes needed to modify the source material.

“Waste Upcycling for Defense (WUD) seeks to advance the science of densification to create efficient ‘green’ methods of turning various types of cellulosic waste into strong, sustainable materials,” noted WUD program manager, Catherine Campbell. “Finished products could greatly reduce the need for re-supply of traditional wood products, such as harvested lumber used in DoD construction and logistics.”

Beyond these enhanced mechanical properties, these materials will need to possess improved durability characteristics necessary for construction materials, including fire resistance, water resistance, and corrosion/weather durability, and be scalable with reduced use of chemical reagents. In addition, WUD aims to determine the potential of using combinations of various cellulosic waste types (scrap wood, cardboard, paper) to produce DoD-relevant materials.

WUD performers will engage with U.S. government and defense stakeholders, as well as appropriate regulatory authorities, to ensure safety and efficacy. This program will have a single phase and take 24 months to complete.

“If successful, technology developed for WUD will pave the way for highly efficient reuse of materials both in support of national security efforts and commercially,” added Campbell.

A Special Program Announcement solicitation with additional details is available at: sam.gov/opp/58b5a1daeb7e4358aeccae496a8f6d16/view.

[1] Cosper, S. et al. Contingency Base Camp Solid Waste Generation, USACE-ERDC 2013. apps.dtic.mil/sti/pdfs/ADA613823.pdf
[2] Song, J., Chen, C., Zhu, S. et al. Processing bulk natural wood into a high-performance structural material. Nature 554, 224–228 (2018). doi.org/10.1038/nature25476