Recycled waste lives on as a cheaper, greener road base material after rocky start

Australia produces about 20 million tonnes of construction and demolition waste each year, but have you ever wondered where it all goes?

Source: Curbed

 
It could have been used to build the road you’re driving on, the shopping centre carpark you use, or it might have formed the foundations for a newly-built industrial building.

About 65 to 70 per cent of building waste produced by the construction and demolition industry is being recycled into new products like hard sands, drainage rock and road base. Any contaminated rubble is generally sent to landfill.

But its potential to build new roads is what the recycling industry is targeting because it uses such large amounts of the product.

“We take local government material such as footpaths, curbing, driveways and we blend that product to produce road base, drainage rock and tracking material,” Resource Recovery Solutions managing director Sam Mangione said.

“We assess the product on arrival, ensuring that it’s not hazardous. We accept the product, it goes through our facility, then we go through a number of processes to achieve the end goal which is a specified engineered product.”

Main Roads ban prompted price collapse

Recycled road base is commonly used in road building on the east coast of the country, but less so in the west.

That is because in 2012, WA’s biggest road builder and potential buyer, Main Roads, stopped using the recycled product after an asbestos contamination scare on a single government project.

“That could have been quite easily dealt with. There’s been a stuff up, let’s deal with it and work through it, and Main Roads were prepared to do that,” Waste and Recycling Industry Association chairman, Michael Harper said.

“But unfortunately the contractor involved got quite belligerent and Main Roads decided this is a lost cause.

“Main Roads since then have refused to use recycled road base because of that one incident, so as a consequence the value of the product has gone down.”
As a result of Main Roads’ decision, other builders followed suit and prices plummeted by around 75 per cent.

“Because Main Roads don’t use it, consultants, local government authorities, developers, all sorts of people have used that as a reason not to use the product because Main Roads are the benchmark,” Mr Harper said.

New testing regime rolled out

The industry set out to develop strict new standards to roll out across the industry.

“A new set of testing regimes has been put in place and those testing regimes will absolutely stop any contamination of any type going into road base, particularly asbestos,” Mr Harper said.

“The regime starts with the demolition contractor, it’s their responsibility to make damn sure he doesn’t send any contaminated concrete to recycling facilities.

“When it gets to the recycling facility, it’s inspected and tested, that’s the first real audit point. Then it’s crushed, it’s tested again by independent auditors to be asbestos free.”

Main Roads has given the testing requirements the tick of approval and confirmed it has committed to using recycled concrete on an upcoming WA road project. It has also earmarked four other major construction developments over the next two years.

“Crushed recycled concrete is a useful road sub-base material under full depth asphalt pavements on heavily loaded roads,” Main Roads said in a statement.

“It can also be used as other road construction layers on lighter trafficked roads. DWER, (the Department of Water and Environmental Regulation) Main Roads and the waste industry are working closely together to ensure that potential contaminants are strictly managed in line with new specifications.”

Subsidy to help industry recover

The City of Canning has been using recycled road base for the past 10 years despite the Main Roads ban.

The city buys around 9,300 tonnes of the material each year and builds 100 per cent of its roads out of recycled product.

“We only buy material that is certified by the Department of Water,” Canning Mayor Peter Ng said.

“Using the recycled material is so much cheaper than using the virgin aggregate, but on top of it … it’s the environmental issue that we have to ensure our environment is well protected.
“We wanted to see our city as a very sustainable city.”

The WA Government has agreed to subsidise the new testing regime for the first six months while the industry gets back on its feet.

Source :

abc net

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