Wood-Infused Concrete Put to the Test

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.

Test site for cellulose nanomaterial-enhanced concrete in Greenville, S.C. Photo credit: Michael Goergen

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.

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FPL researcher Robert J. Moon contributes to “milestone” nanocellulose research

Robert J. Moon is a materials research engineer for the U.S. Forest Service Forest Products Laboratory (FPL) stationed at Purdue University. Moon and his colleagues study the smallest known particles of wood: nanocellulose. The Purdue-FPL partnership builds on the nanotechnology infrastructure and expertise at Purdue University Discovery Park and the wood science expertise from FPL researchers such as Moon.

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Cellulose nanoparticles as viewed through an electron microscope. Wood at the nanoscale is extremely strong and light weight making it an excellent addition to renewable composite materials.

Dr. Moon is a member of the Birck Nanotechnology Center and part of the team investigating the underlying science and technologies of nanodimensional characteristics of wood. Materials at the nanoscale have different properties than those at the human scale. When wood nanomaterials are examined, for example, they exhibit qualities such as high stiffness with light weight and strength characteristics similar to Kevlar.

Recent discoveries regarding nanocellulose will be published in the December issue of the journal CelluloseR&D Magazine lists the primary author as Purdue doctoral student Fernando L. Dri, with co-authors including Louis G. Hector Jr., of the Chemical Sciences and Materials Systems Laboratory at General Motors Research and Development Center; Robert J. Moon of FPL; and Pablo D. Zavattieri, assistant professor of civil engineering at Purdue.

These findings “represent a milestone in understanding the fundamental mechanical behavior of the cellulose nanocrystals.” Cellulose used in nanotechnology applications could come from many different sources including “trees, plants, algae, ocean-dwelling organisms called tunicates, and bacteria that create a protective web of cellulose.”

“Cellulose nanomaterials are inherently renewable, sustainable, biodegradable and carbon-neutral like the sources from which they were extracted,” says Moon. Such “green” nanomaterials, Moon says, “have the potential to be processed at industrial-scale quantities and at low cost compared to other materials.”

This research announcement follows another recent nanocellulose highlight, this one from USDA Secretary Tom Vilsack, demonstrating the the “potential of wood- based nanotechnology to strengthen rural America by creating sustainable jobs and adding timber value while also creating conservation opportunities in working forests.”

FPL Helps Recyclable Solar Cells Take Root

The same building blocks nature uses to produce trees are now being used to enhance high-efficiency products such as photovoltaic solar cells.

By producing pilot-scale quantities of cellulosic nanomaterials, the U.S. Forest Service Forest Products Laboratory (FPL) is collaborating with researchers at the Georgia Institute of Technology and Purdue University to demonstrate the potential of cellulosic nanomaterials as a high performance, environmentally preferable material for the 21st century.

“Using cellulosic nanomaterials as a substrate for photovoltaic cells is just one example of the ability of these materials to provide renewable applications for such high-efficiency products,” said Ted Wegner, Assistant Director of the Forest Products Laboratory.

To date, most solar cells have been built on glass or plastic foundations. Neither is easily recyclable and petroleum-based substrates are not very eco-friendly. Cellulose nanomaterials, on the other hand, are renewable and can be sustainably produced. Use of these wood-based materials also creates a potential use for biomaterials harvested through forest restoration projects aimed at reducing catastrophic wildfires.

“These materials offer a profound opportunity to accelerate forest restoration across America, to protect lives and property from wildfire,” said Michael T. Rains, FPL acting director. “It is estimated that a well-established program in wood-based nanotechnology that creates high-value markets from undervalued woody biomass can help restore 7-12 million forested-acres annually,” said Rains. “This could significantly reduce future fire suppression costs.”

Cellulosic nanomaterials are naturally occurring and possess many outstanding qualities. They have strength properties greater than Kevlar®; piezoelectric properties equivalent to quartz; can be manipulated to produce photonic structures; possess self-assembly properties; and are remarkably uniform in size and shape. Because they are naturally abundant, renewable, and cost-effective, reproduction of cellulosic nanomaterials is expected to reach quantities of millions of tons. This exceeds production projections for many other nanomaterials.

A recent study by Georgia Tech College of Engineering, led by Professor Bernard Kippelen, opens the door for a truly recyclable, sustainable, and renewable solar cell technology.

“The development and performance of organic substrates in solar technology continues to improve, providing engineers with a good indication of future applications,” said Kippelen, director of Georgia Tech’s Center for Organic Photonics and Electronics (COPE). “But organic solar cells must be renewable. Otherwise we are simply solving one problem, less dependence on fossil fuels, while creating another: a technology to produce energy from renewable sources that is not disposable at the end of its lifecycle.”