The project’s lead researcher Dr Mahdi Disfani, who is a senior lecturer at the university’s School of Engineering, teamed up with two Australian tyre-recycling businesses to trial a road base that can support heavier traffic loads.
Although pavements made out of recycled tyres are already a popular option due to the product’s flexibility and resilience, it has typically been unsuitable for roads as it cannot support heavy loads.
{{quote-A:R-W:300-I:2-Q:”Our innovation was finding the optimum blend between the three elements of TDA, crushed rock and binder.”-WHO: Dr Mahdi Disfani, senior lecturer at Melbourne University School of Engineering}}Commenting on the process, Disfani told Quarry that tyre-derived aggregates (TDA) produced by national recycler Tyrecycle were used and mixed with crushed rock and then stabilised with a polymer binder.
“Our innovation was finding the optimum blend between the three elements of TDA, crushed rock and binder to assure the final product is flexible enough when there is no load – traffic, bike or pedestrian – on it but turns rigid when a load is present,” Disfani added.
The trial involved testing four different pavement applications, including a footpath, bike path, cark park and low volume traffic road.
Furthermore, performance requirements – such as skid resistance, pavement movement, water infiltration, run-off, and resilience of the pavement under applied service loads – were rigorously tested to promising results.
Future applications
When asked whether old tyres that are typically used in quarries on rigid and articulated dump trucks could also one day be recycled into road bases, Disfani said it was possible – in principle.
“We did use TDA produced from passenger car tyres and results were satisfactory,” Disfani said.
“It is all about finding an application in which the added tyres don’t just bring enhanced performance; it also needs to be a market competitive solution in order to bring large volumes absorbed into the market.”
Disfani added that stakeholders such as councils, water authorities and developers were encouraged to get in touch for the next stage of the project that is set to be a large trial of the road base under different load types.
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