Building sustainable roads
We are committed to the Queensland Government’s new Waste Management and Resource Recovery Strategy, particularly working towards a circular economy.
Using recycled materials has the potential to deliver significant benefits including cost savings, reducing landfill, protecting the environment and our lifestyle, network performance, circular economy and reducing emission.
While research is continuing, we have already identified ways to reduce waste and emissions to deliver sustainable infrastructure by including glass, tyres, reclaimed asphalt, construction and demolition waste into our roads.
Glass
10% to 20% recycled glass can be used in roads.
We are finding ways to use recycled crushed glass as a substitute for sand and aggregate in road materials. Up to 10% can be used in asphalt bases and up to 20% in gravel bases.
We are continuing to investigate the use of recycled glass in concrete, and as bedding and backfill sand around pipes.
Crumb rubber
We forecast to save 1.1 million tyres from landfill by June 2021.
Used tyres are recycled and processed into crumb rubber, which is blended into bitumen to be used in asphalt and sprayed seals.
Crumb rubber not only recycles old tyres, but can improve the longevity and performance of roads.
Hot-in-place asphalt recycling (HIPAR)
2 milllion m2 of pavement has been recycled using HIPAR
HIPAR removed, rejuvenates and relays existing asphalt in a single pass.
This results in very little waste being sent to landfill minimising consumption of new materials and impacts on traffic.
Reclaimed asphalt pavement (RAP)
Up to 40% RAP can be used in new asphalt.
When asphalt is removed from existing roads it is processed into reclaimed asphalt pavement (RAP) material which can be incorporated back into new asphalt.
The use of RAP provides cost savings, reduces our reliance on raw aggregate and bitumen, and diverts waste from landfill.
Insitu stabilisation
Up to 6,000 tonnes of raw material could be saved per km of road.
Insitu stabilisation of existing roads is undertaken by pulverising the road and mixing various stabilising agents (including cement, bitumen, fly ash and slag) which provides a strengthened rejuvenated pavement.
This results in very little waste sent to landfill without needing to consume new materials.
Construction and demolition waste
Up to 8,000 tonnes of waste diverted from landfill per kilometre of road.
Construction and demolition waste is material recovered from construction and demolition sites such as concrete, brick and
glass, and can be used as an alternative to natural aggregates and sand in road bases.
We are also investigating the use of this waste in concrete.
Rubblisation
We have completed the first rubblisation trial in Queensland.
Rubblisation and 'crack and seat' area used to rehabilitate and recycle existing concrete pavements.
This technique fractures the existing concrete pavement into small, interconnected pieces before a new road is constructed over the top.
Fly ash and blast furnace slag
Up to 70% reduction in greenhouse gas emissions from the use of fly ash.
Fly ash and blast furnace slag are industrial wastes from coal fired power plants and steel production. These waste products can be used to replace up to 70% of the cement used in pavements.
Up to 35% of the cement used in structural concrete can be replaced with fly ash, up to 50% with a combination of fly ash and slag, and 60 - 70% with slag alone.
Current research
We are continually researching innovative technologies and using recycled materials to construct sustainable resilient infrastructure which benefits the environment, community and economy.
Plastics in infrastructure
We are investing in research to understand the opportunities for incorporating recycled plastics into road infrastructure. The research is considering long-term performance benefits for Queensland’s roads as well as the safety and sustainability of the environment and the community now and in the future.
This research is being undertaken as a collaboration with National Asset Centre of Excellence (NACOE) - a joint initiative between TMR and Australian Road Research Board, and Western Australian Road Research and Innovation Program.
Recycled materials in earthworks drainage and concrete
We are exploring new opportunities for the use of recycled materials in earthworks, drainage and concrete, focusing on diverting waste from landfill and supporting a circular economy.
Recycled materials such as glass, bottom ash from coal fired power plants and construction and demolition waste have the potential to be used in these applications.
Resources
- Last updated 23 December 2022