20 November 2023
Tyre Stewardship Australia has funded a demonstration project in Sunshine Coast (QLD) to characterise the practicality and performance of CR Gap Graded mixes using crumb rubber manufactured from 100% end-of-life OTR tyres provided by Boral. The gap graded asphalt mixtures will have higher air-voids compared to dense-graded asphalt mixtures and the higher voids can accommodate the high-viscosity rubber binder in the mix produced from end-of-life OTR tyres. While the current specification in Queensland (TMR PSTS112, AfPA GGA OGA) does not preclude the use of end-of-life OTR tyres, there is limited data to show the effect of this source of rubber in the manufacturing of CRM bitumen and asphalt mixes.
The outcome of the project will provide more information about the OTR tyre-derived crumb rubber and will potentially generate national appetite. This will partially overcome current barriers to the recovery of OTR tyres, hence fostering a more sustainable waste-to-resource approach.
The following deliverables are expected upon successful completion of this project:
• Increased knowledge about the characteristics and impact on binder performance of crumb rubber from OTR tyres
• Support the development of local government specifications
• Clarify the life-cycle benefits when using crumb rubber asphalt compared to conventional dense-graded asphalt.