Plastic, glass paves the way for ?greener? roads

Green Roads PolyPave, which has been developed by leading recycled aggregates producer Alex Fraser Group, was recently used in a resurfacing project in Richmond’s Stanley and Margaret streets, and will be rolled out in other areas.

A total of 7300 two-litre plastic bottles and 55,000 glass bottles was used in the pavement of these two roads. That is the equivalent of 1500 wheelie bins in the annual kerbside recycling collection of Stanley Street.

{{quote-A:R-W:275-I:2-Q:“Laboratory test results showed increased fatigue life, improved asphalt rut resistance, increased asphalt modulus/stiffness, and a better resistance to moisture ingress.” -who:Brendan Camilleri, Asphalt General Manager, Alex Fraser Group}}The City of Yarra has engaged Alex Fraser to repair and repave several more streets in the coming weeks, calling for an additional 1000 tonnes of the sustainable asphalt. This will save another 25,000 plastic bottles from ending up in landfill.

Alex Fraser managing director Peter Murphy said PolyPave was a prime example of how a circular economy could be achieved, with government, industry and community working together to build sustainable infrastructure with recycled materials.

“The City of Yarra’s progressive approach to the use of sustainable material is an excellent illustration of how local councils can proactively reuse the waste generated in their communities to build and maintain their cities,” Murphy said.

He added that this product could reduce the usual carbon footprint of road manufacture by up to 65 per cent.

Product durability

Alex Fraser’s asphalt general manager Brendan Camilleri told Quarry Polypave can be used on all roads and is not restricted to roads where traffic loading is light.

“We are confident PolyPave will perform well on heavily trafficked roads,” said Camilleri, adding that laboratory test results showed an increase in nearly all mix performance and durability parameters.

Commenting on the anticipated life cycle of a road constructed with PolyPave, Camilleri said pavement life was dependent on individual operating conditions, but he did not foresee any lifecycle drop using Polypave.

He said research and development behind the product had ensured there was no slipperiness/loss of skid resistance, loss of strength or shape and the percentage inputted of the recycled plastic ensured the asphalt mix properties were not affected.

Mix design

Camilleri said Alex Fraser’s innovative asphalt plant enabled his team to develop a wide range of asphalt mixes.

“Depending on the mix design, PolyPave is estimated to reduce carbon emissions by over 65 per cent. We can achieve an estimated saving of 10.6 kilograms per tonne of carbon emissions,” Camilleri said.

Camilleri said PolyPave was less sensitive to increased pavement temperatures because the recycled plastic utilised had a higher softening point temperature than that of the bitumen binder used in the asphalt mix.

“[Recycled plastic] being dissolved and dissipated throughout binder, it will increase the softening point temperature of the asphalt mix,” he added.

Camilleri said PolyPave also reduced ultraviolet radiation damage, as the recycled plastic was less susceptible to UV damage than the traditional binder.

Alex Fraser’s asphalt crews pave around 1000 km of roads each year but this is first time they have used plastic – high density polyethylene.

Camilleri said the benefits of plastic are:
• Increased fatigue life.
• Improved asphalt rut resistance.
• Increased asphalt modulus/stiffness.
• Increased wet tensile strength.
• Reduced ultraviolet radiation damage.
• Less sensitive to increased pavement temperature.

“Laboratory test results showed increased fatigue life, improved asphalt rut resistance, increased asphalt modulus/stiffness, and a better resistance to moisture ingress,” Camilleri said, adding that Alex Fraser was “committed to developing a wide range of sustainable asphalt mixes and construction materials”.


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