Construction industry builds a future in sustainable concrete

Forget living in a concrete jungle, this construction staple is getting a makeover from a surprising source saving Aussie suburbs.

Concrete progress is being made in sustainable construction in more ways than one. A revolutionary concrete aggregate made from recycled soft plastics is lighter and smoother to pour and reduces thermal mass once it’s in the ground. Now councils and corporations are essentially buying back their waste by turning recycled soft plastics into footpaths, cycleways, curbing and carparks.

The first major test of concrete aggregate Polyrok was in the exterior of a Coles refurbishment in Horsham, Victoria, which used the equivalent of 900,000 pieces of soft plastic. From that success, the supermarket’s Cobblebank development used in excess of six million recycled plastic pieces in Polyrok pours.

Construction workers pour concrete at the Coles Cobblebank site in Victoria, where six million pieces of recycled soft plastic went into the carpark, footpaths and curbing as a revolutionary concrete aggregate. Picture: supplied

For a country the size of Australia, the potential civic and commercial applications are as limitless as the vast soft plastic problem itself. Indeed, Polyrok spokesman Thomas Hamilton said the value goes far beyond innovations in recycling, manufacturing and concrete.

“There is almost an ethical, moral, environmental imperative to find homes for plastic which isn’t the ground, which then leaks into the water table or is in the ocean,” he said.

“Innovation happens all the time. The really interesting thing is that Polyrok genuinely solves a major issue for the future of humanity and that’s why everyone involved is so excited by it.”

Councils are now using Polyrok in civic projects, finding a sustainable solution that simultaneously improves infrastructure and amenity.

Members of the brains trust behind the Polyrok concrete aggregate: SR Engineering’s Steve Rawson, project manager Kimberley Williams and Replas managing director Mark Jacobsen, surrounded by the soft plastic prime ingredient at the Replas Environmental Centre in Carrum Downs, Victoria. Picture: Rob Leeson.

Sydney’s Blacktown LGA recently used 12.6 tonnes of Polyrok from three million pieces of soft plastic in a new recreational path. Project manager Donato Lucci said the alternative aggregate “complements the concrete composition, the mix. In terms of the workability, it makes it easier to actually spread onsite.”

Coles state construction manager Fiona Lloyd said concrete was the main sustainability opportunity in construction.

“It is the biggest material used in every project, whether for Coles or a normal construction site,” she said.

“We’re using it across most projects in Victoria. It’s starting to go out to the other states as well and becoming quite a standard for us to use.

“Where the site conditions will allow it, we are absolutely looking to implement that in most projects.”

Victorian construction manager Fiona Lloyd pictured with colleague Luke at the Coles Cobblebank site, where six million pieces of recycled soft plastic went into the carpark, footpaths and curbing after being turned into a revolutionary concrete aggregate called Polyrok. Picture: supplied

Turning the initial idea into a tangible, sustainable building product brought together that constant supply of supermarket soft plastic, recovered by the in-store REDcycle program; RMIT University’s testing and data; SR Engineering – and Replas, a leading manufacturer of recycled plastic products.

Engineers Australia CEO Dr Bronwyn Evans said such collaborative advances exemplify Australian engineers leading the circular economy revolution, “with industries that are fuelled by their own waste as a result of smart science and innovative engineering.”

“Concrete made from soft plastics has enormous potential thanks in part to its excellent sound- and heat-absorbing properties,” Dr Evans said.

“Plastics are strong, durable, waterproof, lightweight, easy to mould and recyclable – which makes them perfect for construction materials.”

The completed Cobblebank site, where six million pieces of recycled soft plastic went into concrete works in the form of the Polyrok aggregate. Picture: supplied

As well as roads and footpaths, other sustainable concrete structures could include freeway noise walls and bushfire shelters. Better yet, site feedback is that the soft plastic aggregate is as good as or better than a traditional mineral aggregate mix.

“Easier to screed, easier to work, a bit lighter and better for your back,” said Victorian concreter Joseph Perez.

“I think it’s a bit smoother than normal concrete, it’s good. Who would have thought the stuff you (recycle at the supermarket) would end up in this concrete? It’s a great idea.”

Towards a Better Future, in conjunction with Coles’ Better Together strategy, will share stories on Farming, Local Communities, Health & Wellbeing and Sustainability/Food Waste to shine a light on the people, charities and organisations that are helping make our country a better place to live.