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Researchers convert agricultural waste to building materials

University of Melbourne researchers examine how grapevine prunings can be mixed with softwood chips and resin, before being converted into particleboards

|Oct 8|magazine8 min read

Researchers at the University of Melbourne are examining how plant and crop waste can be converted into recycled building materials, thereby minimising waste and improving sustainability within the construction industry.

While agriculture is one of Australia’s most important industries, it also produces millions of tons of plant and crop waste each year. This waste comprises a diverse range of wood-like material, such as rice husks, flax shives, wheat straws, bagasse, canola stalks, oat hulls and grapevines. Globally, crop waste production is approximately 3.7 billion tonnes per year.

Despite this abundance of waste, there are very few ways to recycle such a massive amount of material, with most of it returning to the soil or burnt. However, both these processes release huge amounts of greenhouse gases into the environment. Therefore, it is imperative to find ways to reuse and recycle this crop waste, especially in a future where there is increasing competition for resources and materials. In addition, it also enables the industry to help boost the economy and environment.

The university report notes that breakthrough research from the University’s Department of Chemical Engineering’s Ellis Research Group – led by Professor Amanda Ellis – shows how these recycled waste materials can be made into useful building materials.

“As the human population increases worldwide, the global demand for particleboard is growing rapidly and the need for woodchip is rapidly outstripping supply.

“Particleboard’s niche within the construction industry is a result of the fact that it’s commonly produced from post-industrial recycled waste wood and sold at a correspondingly low price – but the increasing demand and cost of production are rapidly making it less attractive,” the report notes. “By making particleboard from another low-cost source, we would ensure the viability of the industry, and the future of an environmentally-friendly building material.”

Globally, grapevine prunings represent a major source of agricultural crop waste, with an estimated 42 million tonnes disposed of yearly. Grapes are also grown almost everywhere, but importantly in countries like China, the US, Australia, France, and Spain – which all also all major producers of particleboard.

Therefore, the grapevine waste could be used to replace the pine chip in particle board, which would help minimise import and transportation costs. The waste can be easily milled into chips using existing chips and mixed with softwood chips and resin to make a hybrid grapevine-softwood particleboard.

By adding as little as 10 percent grapevines into the particleboard, the boards exceed all industry and durability standards, without changing any aspect of the existing process, the report adds.

“While 10 percent doesn’t sound like a lot, the scale of particleboard production globally means that even replacing as little as this much of the soft woodchips relieves the pressure on supply while also reducing grapevine waste.

“In fact, substituting 10 percent of softwood for grapevine in Australian particleboard production alone could reduce the demand for wood by tens of thousands of tonnes annually,” the report points out, adding that these considerations enable manufacturers to switch to more sustainable materials, without altering the strength, durability and reliability of their products.

“The next steps in our research involve running a pilot trial of grapevine particleboards in a factory and conducting a business case analysis to determine the overall cost of replacing wood with grapevine.

“But our findings have the potential to not only reduce the amount of pollution from crop waste disposal, but to also ensure particleboard can remain a cheap, staple construction material into the next century,” it concludes.

University of Melbourne research
Construction Global magazine