The recycled building blocks of the future

Supermarket bags, milk bottles and sawdust could be turned into building blocks, thanks to technology developed at the University of Canterbury’s wood technology research centre.

shusheng pang composite building material

Shusheng Pang has discovered a practical use for some of the 160,000 tonnes of unwanted plastic that goes to New Zealand dumps each year, repurposing recycled plastic and sawdust into a composite building material. 

The product would be suitable for decking, joinery and panelling in a house or outdoor playgrounds as a substitute for chemically-treated wood.

"New Zealand uses at least 200,000 tonnes of plastics a year and only 35,440 tonnes are recovered with the rest ending up in landfills. Wood in its original form swells when it gets wet and shrinks when it is dried," Pang said.

"If not properly designed and constructed, wood stability and durability can be a concern for wooden structures such as leaky houses. Currently wood is chemically treated for building purposes if high durability is required."

Pang's composite material wood-plastic composite, on the other hand, remains stable when exposed to water and extreme temperature conditions.

Pang, who will deliver a free public lecture on the breakthrough at UC campus on August 29, is in discussion with potential partners to build a plant for production of the wood-plastic products, probably based in Christchurch.

Although a wood-plastic product has been applied in North America and Europe before, Pang said using recycled plastic for building materials is novel.

"We want to bring our product to market so Kiwis can use alternative materials they use to build their homes. At the same time, we've discovered a practical use for the plastic clogging up our landfills. It's very much a win-win solution.’’

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