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How recycled road base is being used in Australian construction

Roads made from recycled plastic and asphalt

Teamwork, Group of workers on a road construction, team of people at work

Australia’s local governments are becoming key players in the creative use of waste thanks to an increased focus on building roads made from recycled plastic and other materials.

One of the best ways to prevent valuable waste going to landfill is to recycle materials for use in road construction. Regular asphalt roads use tons of raw materials, but recycled road base incorporates crumb rubber, crushed concrete, recycled asphalt, plastic bags, waste toner from used printer cartridges, glass and more. These recycled materials are changing the way local governments approach road building.

Every year, Australia uses 200 million tonnes of quarried sand, rock and gravel. That’s eight tonnes per person. The nation produces 67 million tonnes of waste annually, and only about 55 per cent is recycled. Using recycled road base in road construction can greatly improve these statistics.

However, different factors, such as site conditions, traffic volume, environmental considerations and the availability of materials, must be considered in each new recycled road project for optimum performance.

Establishing AUS-SPEC standards
To make all recycled roads safe and durable, designers, engineers, building professionals and governments need specifications.

AUS-SPEC is the national local government specification system. Managed by NATSPEC, it is a joint venture between NATSPEC and IPWEA. AUS-SPEC is an essential technical resource for council staff and contractors to design, construct, operate and maintain high-quality infrastructure in a cost-effective way.

Since March 2020, NATSPEC has been participating in a joint research project with Sustainability Victoria, IPWEA Victoria, the Civil Contractors Federation and the Office of Projects Victoria. The project aims to reduce waste sent to landfill by using recycled materials in local roads. For AUS-SPEC, the project will culminate in the development and publication of specifications that stipulate the use of different recycled materials in road maintenance, construction and renewal. Phase 2 of the project began in mid-May 2020 with the release of a survey sent out to all local councils. The survey responses will give AUS-SPEC a clearer idea of how best to support local governments in their recycling aims.

Local governments have been the trailblazers in Australia when it comes to recycled materials in roads. AUS-SPEC received 65 responses to Phase 1 of the project from local councils around Australia, offering their experiences with recycled materials in road works.

In February 2020, the first Australian road made entirely out of recycled materials opened in central Adelaide. Chatham Street is now made from reclaimed asphalt pavement and recycled vegetable oil from local producers, a combination 25 per cent stronger than standard asphalt. Just north of the City of Adelaide, the City of Salisbury was the first South Australian council to complete a road made with 70 per cent recycled materials.

Using recycled asphalt road base
Reclaimed asphalt pavement (RAP) is among the most popular recycled materials; Georges River Council, the City of Tea Tree Gully, Redland City Council, the City of Mitcham and Latrobe City Council have all used RAP in their local roads, in volumes ranging from ten to 75 per cent.

Campbelltown City Council has used RAP since 1990. There is an imbalance in the use of recycled materials between metropolitan local government areas and rural and regional local government areas, largely due to differences in access to recycled content. AUS-SPEC’s recycled materials in roadworks specifications will contribute to reducing this gap.

Research into recycled materials has led to the creation of new products. Reconophalt, an initiative by integrated services provider Downer and recycling organisation Close the Loop, was trialled by Hume City Council in northern Melbourne in May 2019, and by the Sutherland Shire Council in NSW in August 2019. In 250 tonnes of Reconophalt, there are approximately 200,000 plastic bags, 63,000 glass bottles, toner from 4,500 printer cartridges and 50 tonnes of reclaimed asphalt pavement.

Reconophalt has superior deformation resistance and demonstrates up to a 65 per cent improvement in fatigue life. Similar benefits are seen from the product TonerPave, which the City of Sydney first used in 2014. TonerPave combines recycled printer toner with warm mix asphalt to produce a longer-lasting road surface with lower maintenance costs, higher energy efficiency and greatly reduced carbon emissions.

Making roads from recycled plastic
Australian roads are part of a worldwide recycling movement. In 2002, the southern Indian state Tamil Nadu began building roads with shredded waste plastic melted into the asphalt mix. A single kilometre of plastic tar road uses the equivalent of one million plastic bags, saves one tonne of asphalt and costs about eight per cent less than a standard road. These roads are exceptionally weather resistant. There are no cracks or potholes after floods, and the road doesn’t buckle in extreme heat, making plastic tar also very popular in the Middle East. In rural Canada, polymer modified asphalts are used to prevent cracks in the road surface after the winter cold.

In Europe, one kilometre of France’s longest motorway was resurfaced with entirely recycled asphalt last October. A mobile asphalt plant produced 3,000 tonnes of recycled material and significantly reduced greenhouse gas emissions. The Dutch initiative PlasticRoad came to fruition in late 2018 with two 30-metre bike paths, each containing recycled plastic equivalent to 218,000 plastic cups.

Guaranteeing safety in recycled roads

Australia’s performance-based building regulations encourage innovation. With AUS-SPEC, local governments have the technical expertise they need to maximise infrastructure sustainability while enhancing the well-being of their community now and in the future. AUS-SPEC is updated every October in response to changes to Australian Standards, Austroads guides and industry practices.

AUS-SPEC specifications already include the use of a number of recycled materials in different specifications, as mentioned in the draft TECHnote GEN 028 ‘specifying recycled material for road works using AUS-SPEC’ that was released with the Phase 1 Project Report.

The recycled materials research project will allow AUS-SPEC to expand the specifications’ scope and respond to local councils’ interests and needs. This will provide a uniform approach to the incorporation of recycled content in roadworks, making local roads safer and more environmentally friendly across Australia. AUS-SPEC is the essential technical resource for local governments when they are paving the way to a greener future.

AUS-SPEC is managed by NATSPEC and jointly owned by NATSPEC and IPWEA. NATSPEC is a not-for-profit, government- and industry-owned organisation and maintains the National Building Specification for Australia. It has been a valued part of the construction industry for more than 40 years.

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