A fast-growing council in Melbourne’s outer west is exploring new ways to deliver the city’s infrastructure needs, and overcoming recent recycling plant closure challenges, through the use of soft plastics in road resurfacing, and using glass to build new footpaths.
Wyndham City Council has recently launched two new trials which use recycled materials to resurface roads, and also build new footpaths.
The footpath trial, in partnership with Swinburne University, has seen crushed glass and recycled plastics used in the mixture to build footpaths.
Wyndham City Mayor, Cr Mia Shaw, said the newly developed cement mix formula included plastic and glass fines for the base and top layers of the footpath.
“At Wyndham City, we’re very interested in exploring new and innovative ways to deal with waste,” Cr Shaw said.
“We have partnered with Swinburne University for this trial, which explores the potential of using recycled plastics and glass in the aggregate materials for concrete footpath construction.
“The concrete was laid in early March at Geddes Crescent Reserve in Hoppers Crossing, and the research team from Swinburne will now monitor the performance of the concrete and conduct tests on the samples collected.”
The 200m long concrete footpath contains more than 199,000 recycled glass and plastic bottles. Monitoring over the coming months will assess compliance with Australian construction standards, with the concrete mix design hopefully made available for use in other council infrastructure across Victoria.
Cr Shaw also thanked the State Government for a Sustainability Victoria grant of $72,000 that made this trial possible.
Saving plastics from landfill
In a separate trial, Wyndham City has resurfaced three busy roads with repurposed soft plastics.
“Again, this trial is all about being innovative and sustainable in delivering infrastructure for our residents,” Cr Shaw said.
“In these sections of road we’ve used the equivalent of 705,000 plastic bags, 50,000 glass bottles, toner from 16,000 printer cartridges, and 250 tonnes of reclaimed road asphalt.
“All materials used for this trial are sourced from the metropolitan Melbourne region, which also saves us on transportation costs.”
Normally, glass fractions of a certain size cannot be recycled, so they are sent to landfill. Downer, the contractor who Wyndham City engaged to deliver these works, secured these fractions which are crushed to a smaller size. This glass is then used as a sand replacement material in asphalt. Glass asphalt is basically the same as conventional hot-mix asphalt, except that between five and ten per cent of the rock or sand aggregate is replaced by crushed glass.
“The benefits of using glass over sand are exciting,” Cr Shaw said.
“Glass is readily available in most locations, and has a lower moisture content than sand, which requires less energy to dry and heat.
“It also alleviates the requirement to dredge or mine limited natural resources.”
Environmental and community benefits
At present, in Victoria, between 50,000 and 60,000 tonnes of crushed glass is sent to landfill. Cr Shaw said working with contractors to reduce the amount going to landfill is not only beneficial locally, but for the environment more broadly.
“This is a way of repurposing our waste into upgrading our existing assets, while reducing wastage.
“With our population growing at such a rapid rate, not only is our need for improved road infrastructure on the rise, but the amount of waste and recyclables coming out of households is also on the rise.
“That’s why we’re exploring different ways of meeting these demands, and finding new and innovative ways to repurpose these recyclables.
“Imagine a city where all our roads are upgraded using recyclables. Ten recycled bottles per household a week based on our population equates to about 2.5 million bottles. This could deliver 10,000 tonnes of asphalt for our local roads.”