Road resurfacing

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Sustainability innovations in road resurfacing across the ACT are helping to reduce greenhouse gas emissions, re-use waste products and extend the life of pavements to keep costs down.

As part of the ACT Government’s Climate Adaptation Strategy, trials of new innovations are increasing the ability of our community to adapt to climate change impacts, reduce greenhouse gas emissions and build a more sustainable city.

Extending the life of a Canberra road through rejuvenation, a process of ‘painting’ the surface without aggregate

Innovation

Road resurfacing using recycled materials was first trialled in 2016. Recently, a range of innovative treatments have been introduced to optimise resource use and reduce lifecycle costs across the city’s road maintenance program. These are:

  • Microsurfacing
  • Cape seal
  • Rejuvenation
  • Low carbon reclaimed asphalt pavement
  • Crumbed tyre rubber binder

Details

Microsurfacing is a very effective corrective treatment for shape, skid and noise problems. It consists of a layer of asphalt emulsion with finely crushed stone. Its application does not require hot temperatures, saving energy and cost.

Cape seal is microsurfacing in combination with another process called chip (gravel) seal. Cape seal is used for cracking and is effective for reducing noise and in situations where there are high numbers of turning vehicles. It also is a lower heat (low energy use) product.

Low carbon asphalt, also called reclaimed asphalt pavement, substitutes toner cartridge powder and recycled asphalt for new materials and uses less heat in its application. The mixture is estimated to save 14 kg of carbon dioxide equivalent (CO2-e) per tonne of product used, compared to other asphalt mixtures. This product is now widely used in Canberra’s streets for re-sealing projects.

All three of the above pavement products are applied at cooler temperatures than traditional hotmix, meaning they take less energy to produce, leading to lower greenhouse gas emissions.

Crumbed rubber from recycled car tyres is 18% of the binder used in asphalt. This has improved performance and strength for heavily trafficked roads.

Rejuvenation treatment extends the life of asphalt by ‘painting’ without any aggregates which saves use of quarry materials and does not waste the existing pavement.

A suburban Canberra road that has been maintained using microsurfacing

Sustainability Benefits

  • Lower greenhouse gas emissions from using eco-friendly resurfacing techniques that require less energy to heat and from using reclaimed waste materials saving emissions per tonne of product.
  • Reduces waste sent to landfill.
  • Reduces use of new quarry materials.

Co-benefits

  • No cost or durability difference between traditional and recycled asphalt mixtures.
  • Extended life of pavements reduces lifecycle costs.