Repaving a parking lot isn’t generally something we’d get too excited about here at the Forest Products Laboratory (FPL). That is, unless the project incorporates wood, in which case, we’re totally stoked.
And that’s exactly what happened in Greenville, South Carolina, at the headquarters for the U.S. Endowment for Forestry and Communities (Endowment). A parking lot there has become the largest test site in the world for cellulose nanomaterial (CN)-enhanced concrete, which FPL researchers and partners at the Endowment, Oregon State University, and Purdue University have found to have improved properties over traditional concrete.
The addition of CN to concrete produces a stronger product which has significant advantages over traditional mix, said Dr. Jason Weiss of Oregon State University. By adding CN, there is a 15 percent gain in product strength. Thus, products could use fewer raw materials and perform just as well.
A side-by-side comparison was set up in the Endowment’s 25- by 45- foot parking lot by pouring 32 tons of concrete enhanced with CN next to an equal amount of traditional concrete. Two smaller tests are being conducted on a sidewalk at FPL and a county bridge deck in northern California. The long-term goal is to test how well the CN compares to traditional concrete when it comes to reducing carbon emissions, materials used and cost.
Addition of these materials could have significant impacts on the environment as well. Concrete is largely a mix of small rocks (aggregate), sand, water and cement. Manufacturing cement is an energy intensive process that constitutes about 4 percent of worldwide greenhouse gas emissions. The cement and concrete industries are actively working to reduce the carbon footprint of their products with CN being among the most promising options.
By adding CN to concrete the mixture causes more of the cement to react than in a traditional mix thereby enabling less cement to be used resulting in a reduction in greenhouse gas emissions with equivalent or increased strength. There are other benefits as well, as these materials are not particularly expensive. So, it could be possible to have a win for the planet and for the pocketbook.
But there are even more wins in the forest, said FPL Assistant Director Alan Rudie. Forest managers are working to restore forests and reduce the risks of catastrophic wildfire and other threats. These management activities largely target low value wood with few markets.
“Removing low value wood is expensive, so finding markets is critical to forest health and sustainability,” Rudie said. “Products made with CN could provide one of the most important answers to keeping our forests as forests and ensuring their health and sustainability.”