Award: Drywall Waste Block, a Green CMU

The masonry block, a workhorse of modern construction, has been a target for innovation since the 1920s, when Frank Lloyd Wright built the first of his “textile block” houses to demonstrate the beauty of inexpensive materials. Its latest reinvention comes from Washington State University (WSU) courtesy of WSU School of Design + Construction professor Taiji Miyasaka and adjunct professor and fabrication labs manager David Drake. The duo wanted to find a use for discarded gypsum drywall, which accounts for 10 million tons of landfill waste in the United States each year.

Courtesy Taiji Miyasaka, David Drake, and Zaky Ramadhan

“We realized that drywall scraps have little commercial value and are not recycled well,” Miyasaka says. He and Drake hit upon the idea of making building blocks out of pulverized drywall, which they say is less expensive than other drywall recycling initiatives. Their technique is simple enough to be DIY, but also scalable with potential industry-wide impact. “We can produce hundreds of these blocks with equipment that could fit in the back of a pickup truck,” Drake notes.

Manufacturing a drywall waste block (DWB) entails the shredding of drywall scrap, acceptable straight from construction or demolition sites; the addition of water and cement; and compaction of the mixture into standard molds at high pressure. Even the paper facer of the drywall can go right into the mix, increasing the blocks’ strength and insulation value, and saving on processing costs.

Courtesy Taiji Miyasaka, David Drake, and Zaky Ramadhan
The pressing process for a drywall waste block can occur on-site using portable machines or off-site using existing machinery at conventional CMU plants.

The project drew enthusiastic responses from the jury. James Garrett Jr., AIA, said, “This is radically useful and radically simple at a time when so many products are trying to call attention to themselves by being unusual.” DWB is “very inventive,” Carrie Strickland, FAIA, agreed. “I could really see it be produced at a high level.”

Preliminary strength testing indicates that DWBs behave similarly in compression to conventional CMUs, but at half the weight. Even more remarkably, DWBs are excellent insulators, with an estimated R-value 10 times greater than that of their concrete counterparts. While DWBs could be produced with industry-standard CMU manufacturing equipment, the WSU researchers say, the production process could be mobile as well, allowing builders to recycle scrap on site or anywhere convenient. “You can set up a station where it’s needed and then move it to another place,” Miyasaka says.

Courtesy Taiji Miyasaka, David Drake, and Zaky Ramadhan
DWB test samples

Courtesy Taiji Miyasaka, David Drake, and Zaky Ramadhan
Compression strength testing of DWB sample

Next up for Miyasaka and Drake are a series of performance tests of full-scale DWB wall assemblies to ascertain R-values, strength, freeze-thaw behavior, and water absorption under different combinations of reinforcement, mortar blends, and insulated and uninsulated cores. At least one commercial manufacturer has already expressed interest.

Juror Craig Curtis, FAIA, noted the project’s significance as comparable to “the introduction of fly ash into concrete, which now is commonplace. … I honestly think this could become a commodity product.”

Still, the researchers acknowledge, introducing a load-bearing exterior block product to market could take a decade due to the extensive and requisite third-party testing to certify its safety and performance. Meanwhile, Miyasaka and Drake are exploring nonbearing DWB applications, such as interior wall cladding, flooring, and exterior hardscaping and seating, and have already produced several concept samples with different colors and textures. “It’s not good enough to do a product that’s cheaper or greener than existing products,” Drake says. “You’ve got to do something that’s both less expensive and higher performing.”

Project Credits
Project: Drywall Waste Block
Project Team: Washington State University, Pullman, Wash. . Taiji Miyasaka, David Drake (principal investigators); Fadil Zaky Ramadhan, Ping Fai Sze (research assistants)
Funding: AIA Upjohn Research Initiative Grant, Amazon Catalyst Grant, National Science Foundation I-Corps, Commercialization Gap Fund
Special Thanks: Washington State University . Voiland College of Engineering and Architecture tech shops; Composite Materials and Engineering Center