Washington State University (WSU) researchers and the not-for-profit Composites Recycling Technology Centre (CRTC) are working together to create new mass timber materials from heat-treated wood and carbon fibre recycled from Boeing airplanes. 

Inspired by Washington State’s recent building code change, which allows the use of Cross Laminated Timber (CLT) and other forms of engineered wood in buildings as tall as 18 stories, the team is investigating ways to convert timber into a more durable, stable construction material. 

Their focus is on thermal modification, which according to WSU, makes the wood more resistant to decay, and less prone to shrinking and swelling as moisture conditions change. 

However, thermal modification will slightly reduce the strength of the wood. To restore its strength, the researchers are adding recycled carbon fibre—which costs about one-tenth of virgin fibre—to the CLT. 

A demonstration panel for the first phase of the project will be displayed in March, at the 2019 International Mass Timber Conference in Portland, Oregon. 

Detailed cross section image of timber

Carbon fibre-reinforced wood (CFRW) is not a new concept in the global building industry. In 2015, Japanese chemical technology company Teijin Limited announced that it was developing the advanced fibre-reinforced wood (AFRW)—a structural timber product comprising a number of layers of dimensioned timber and high-performance fibres bonded together with structural adhesives.

“CFRW, laminated timber that includes layers of highly rigid, thin-walled carbon fibre, achieves twice the flexural rigidity of conventional laminated timber. [It also] offers enhanced durability and design qualities for use as structural beams,” Teijin explained in a release. “The targeted development of AFRW, a more advanced material, is expected to extend applications to medium-rise buildings.”

Diagram of engineered timber from recycled carbon fibre

In September 2018, Teijin announced it would be constructing the world’s first AFRW building, to be located at its Tokyo Research Centre. 

The new building will exploit the warmth and unique timber composition of AFRW to help create a stress-free environment. It also aims to create an open and comfortable space by avoiding the use of columns, thus maximising the inflow of natural light. 

Render of residential house with engineered timber

Render of residential interior with engineered timber

Upon completion of the project, Teijin and professional construction firm Maeda Corporation will monitor the adhesive stability and the vibration durability of AFRW for a period of seven years. The company will continue to develop its AFRW technology following the construction of this first building and the initial monitoring phase.