Paving our recycled future: ARRB

The road construction industry can contribute to the circular economy by creating sustainable roads for a sustainable society, writes Melissa Lyons, Senior Professional Leader, the Australian Road Research Board.

Sustainability, recycling, circular economy – these are the current buzz words in the road construction industry.

The road construction industry is under pressure to help solve Australia’s recycling crisis. The make-up of roads lends itself well to the incorporation of recycled materials.

However, this is not as simple as replacing raw road construction materials with recycled materials such as glass, plastic or rubber. The right approach must be taken.

We need to think about how we can incorporate recycled materials into our roads in way that will make the road more sustainable in the long term, rather than a way to help solve the recycled material stockpile issues we have now.

Without the right research, development and planning, we risk creating a new waste stream in years to come if we can’t reclaim the road.

Roads play an important role in our transport system. They keep our economy moving. We need to ensure we are not de-valuing or degrading them. Roads are not ‘just’ asphalt, they are valuable assets that need to meet certain requirements for our society to function.

The road construction industry should be designing and constructing our roads with the confidence that they will meet or exceed current standards. Society still expect our roads to perform well, if not better, especially as technology progresses.

However, these roads also need to be sustainable in order to support a more sustainable society.

Society is heavily influenced by marketing and it is also influencing the way our industry is embracing sustainability. It is important that the road construction industry support the basic principles of the waste hierarchy – reduce, reuse, recycle.

We need to be careful to not give society justification to keep generating recycled waste.

Standard asphalt is 100 per cent reusable as Reclaimed Asphalt Pavement (RAP). The use (and re-use) of RAP reduces the amount of virgin materials used in maintenance, rehabilitation or new construction of asphalt and pavements.

This means valuable materials are used over and over again and do not end up in landfill, directly contributing to a circular economy.

There are many aspects to consider across the pavement lifecycle. There are many innovative products using recycled materials on the market and laboratory tests that show positive performance results.

However, many of these products have not considered the full cradle-to-grave lifecycle of the recycled materials and the road. Recycled materials in some cases may increase the performance of the road, but it may also change how it is processed and manufactured and how we can reuse it.

Therefore, we need to make sure we think about how our current processes and equipment will need to be updated to be compatible with the new products we are creating.

There may be trade-offs and risks with adding new recycled materials. There are costs and benefits of each material, use and design.

For some recycled materials there may be more valuable and lower risk road infrastructure applications that can use more recycled materials e.g. bike paths or roadside furniture.

Full life-cycle assessments of road technology options can assist in the best technology selection for the right situation.

For the road construction industry to contribute to a circular economy, we need to make a conscious effort to not just offer short term solutions to our recycling crisis.

When we incorporate recycled materials into our roads and road infrastructure, a rigorous research and development process should be undertaken.

Learnings from international uses, laboratory testing and local demonstration trials with performance monitoring are all part of this.

ARRB are working with state road agencies, local government and bodies such as Sustainability Victoria and Tyre Stewardship Australia, undertaking trials and developing standards and guidelines to ensure the smart implementation of recycled materials.

Interested in finding out more about this work and its potential application, or customisation to your needs? Contact ARRB at sustainability@arrb.com.au