Hockey field redevelopment using recycled aggregate

Published: 6 December 2021

Product and material information


Product	Aggregate
Product name and supplier	Polyrock by Replas
Recycled material/s contained in product	Recycled plastic aggregate consists of 95% Red Group post-consumer soft plastic waste and 5% engineering recycled content
Percentage of recycled material in product	100%
Total volume of recycled materials used	7 tonnes, equivalent to 1,000,000 plus plastic bags
Product specifications and standards	NATA testing
Location	City of Darebin, KP Hardiman Hockey Field, 867 Plenty Road, Kingsbury Victoria 3083

Project background

Darebin Council undertook a significant restoration and upgrade of its KP Hardiman Hockey Field using recycled products and materials. The restoration included:

shock pad material made of approximately 98% recycled car and truck tyres
concrete containing recycled soft plastic, asphalt containing recycled plastic polymers
trench bedding materials containing recycled crushed glass in conduit
seating containing recycled plastic
re-seeding additive using recycled paper mulch for reinstating the surrounding grass areas.

The KP Hardiman Hockey Field and Lighting Redevelopment project was one of the City of Darebin’s two flagship construction projects for the 2021.

For redevelopment projects of this kind, Darebin traditionally used conventional products, including virgin quarry materials. By prioritising the use of recycled materials in the planning and procurement stages of this project, Darebin Council incorporated over 236 tonnes of recycled materials (such as glass, rubber, plastic and concrete) into its infrastructure.

City of Darebin Mayor, Councillor Lina Messina said these projects show what can be achieved when the circular economy was prioritised in demolition and construction work.

“We hope this project will become an inspiration for individuals, businesses and organisations across Victoria to take up the use of recycled materials and these exciting new technologies. Recycled materials are no longer a novelty. Their use will and must become a priority for how we design and build for our future.”

Councillor Lina Messina, City of Darebin Mayor

As an International Hockey Federation (FIH) accredited hockey field, the KP Hardiman redevelopment shows that high-quality outcomes are possible when sustainable materials are prioritised in infrastructure projects.

This project was supported by Sustainability Victoria’s Sustainable Infrastructure Fund.

Procurement

In this project, the Darebin Council worked with their contractors, Polytan, to explore opportunities to incorporate recycled materials in place of virgin materials. Polytan provided the Darebin project team with information on different sustainable alternatives to virgin materials, which were supported by case studies outlining previous successful use of these products.

During the procurement process, the Darebin project team considered:

supply availability in commercial quantities
guarantee and warranty certificates
meeting performance criteria
not endangering the hockey fields existing FIH certification
other financial and timing issues

For products not commonly used, the procurement effort was greater. For example, council officers struggled to find a concrete batch plant supplier that could supply enough volume for their concrete pours using the Polyrok concrete mix.

City of Darebin Senior Project Manager, Oliver Nellessen said “the biggest challenge was to find a concrete batch plant that was willing to:

Use the Replas plastic aggregate as additive or replacement in its concrete composition.

Add the plastic aggregate by hand into the mix because the batch plant logistics are generally not set up for this to occur automatically.

Provide the mix in large concrete trucks rather than mini mixers to avoid ‘cold joints’ on site and result in a commercially viable operation.

Clean and dispose of any residue in the delivery vehicle mixer drums thoughtfully.”

Despite these challenges, prioritising the use of recycled and reused products highlighted what could be achieved in a cooperative project environment, while not ignoring important issues such as performance, future maintenance obligations and affordability. Funding through Sustainability Victoria’s Sustainable Infrastructure Fund helped offset the additional costs incurred due to the use of uncommon construction materials, thereby managing financial risk.

Installation and product performance

The concrete subcontractor reported during construction that the workability of the recycled plastic concrete was very similar to working with ‘non-plastic’ concrete. Darebin Council said “the difference was in providing the specified ‘broom finish’ to the finished path surface that required precise timing and additional effort. The project manager instructed an increase in concrete strength from 25MPa to 32MPa for a standard 25MPa concrete pavement, to err on the side of caution”. Both 28-day and 56-day test results were satisfactory.

Lifecycle monitoring and maintenance

The hockey field is in the early stages of being evaluated as it has had little playtime on its surface due to COVID-19 related lockdowns.

More information will be available following the 12-month monitoring period ending June 2022.

Gallery

45 tonnes of waste tyres were recycled into the shock pads installed under the synthetic turf at the hockey field.
A 10% recycled concrete aggregate mix was used for pathways, containing 7 tonnes of recycled soft plastic; the equivalent of 1 million plastic bags.
Recycled plastic benches containing 90% recycled hard plastics from Replas, are aesthetically pleasing, complimenting the other recycled materials used in the project.

Contact us

For more information about the project, please contact sustainableprocurement@sustainability.com.au.

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