Darwin researchers explore tyre-derived road strength
Researchers at Charles Darwin University are investigating whether old tyres can be repurposed to create stronger, longer-lasting roads in the Northern Territory’s challenging climate. With around 400 tonnes of tyres discarded annually by Darwin residents and commercial operators, the study asks: can recycled rubber provide a practical and environmentally responsible solution for road construction and maintenance?
Why tyres, and why now?
The NT endures extreme heat, heavy rainfall during the monsoon, and intense sun exposure all year round. Traditional road materials can crack, deform, or degrade quickly under these conditions. Tyre-derived materials, particularly crumb rubber and rubber-asphalt blends, offer potential benefits: improved flexibility to resist cracking, better skid resistance, and enhanced drainage. By incorporating end-of-life tyres into road pavements, engineers hope to reduce maintenance costs and extend service life without increasing carbon footprints.
What does the research involve?
The CDU project examines several approaches to tyre reuse, including:
- Crumb rubber asphalt (CRA), where shredded tyres are mixed into asphalt to improve elasticity.
- Rubber-modified binders, which alter the asphalt’s viscosity and performance at high temperatures.
- Structural layers that incorporate recycled tyres in sub-base or cushion layers to dampen loads and reduce pavement rutting.
Researchers are conducting lab tests and field trials to assess longevity, skid resistance, noise reduction, and environmental impact. A key focus is ensuring the materials meet safety standards and do not release harmful substances during lifetime use or end-of-life recycling.
Potential benefits for the Northern Territory
If successful, tyre-derived road materials could offer several advantages in the NT context:
- Enhanced durability: Added elasticity helps roads better absorb heavy vehicle loads and temperature fluctuations.
- Cost savings: Longer service life could reduce frequent resurfacing and maintenance costs for remote and high-traffic routes.
- Waste reduction: Approximately 400 tonnes of tyres are discarded annually in Darwin, a number that could be diverted from landfills.
- Improved safety: Increased skid resistance and better drainage lessen the risk of accidents during wet and hot seasons.
Challenges and considerations
While promising, tyre recycling in road construction faces hurdles. Processing costs, supply consistency, and regulatory approvals must align with local standards. Researchers also seek to understand long-term environmental impacts, including potential leaching or microplastic concerns and how tyre materials perform under the NT’s unique weather patterns.
Community stakeholders, including local councils and road authorities, are watching closely. If the approach proves viable, it could become a model for other remote ecosystems facing harsh climates, limited funding, and high maintenance demands.
What comes next?
CDU researchers plan further field trials, collaborating with industry partners to refine mix designs and assess performance across different road types, from rural arterials to urban distributors. The project could pave the way for broader adoption of sustainable, resilient pavements that turn a waste stream into a valuable infrastructure resource.
Conclusion
Repurposing old tyres for road construction represents a compelling convergence of waste management and civil engineering. In Darwin’s climate, tyre-derived solutions may offer stronger, longer-lasting roads while reducing landfill and supporting a more sustainable transport network for the Northern Territory.
