Rubber recovered from about 264 end-of-life car tyres has been incorporated into a resurfacing project on one of central Hamilton’s busiest streets.
Connect Hamilton has partnered with Road Science to trial FlexiPlus Bind EcoBlend, an asphalt binder containing devulcanised rubber recovered from used tyres.
Connect Hamilton is a partnership between Hamilton City Council and Downer New Zealand responsible for managing, maintaining and renewing the city’s transport and roading infrastructure.
Road Science is a New Zealand-based designer and supplier of bitumen, bitumen-based products and road pavement solutions. It operates as part of the Downer Group.
The trial material has been laid on two sections of Anglesea Street between Mill Street and London Street, with the remainder of the site using a conventional polymer-modified binder as a control.
Road Science and Connect Hamilton will monitor the sections to compare the long-term performance of the two binders.
The project used approximately 1320kg of recycled tyre rubber and follows a Road Science trial with Auckland Transport earlier this year.
Around 6.5 million tyres reach the end of their useful lives in New Zealand each year.
Connect Hamilton design and renewals manager Nikhil Vishwanath says the trial could demonstrate a practical use for some of that material.
“We’re constantly looking for innovative ways to reduce our environmental footprint while continuing to deliver reliable infrastructure outcomes for Hamilton,” Vishwanath says.
“FlexiPlus Bind EcoBlend enables us to offset tyre waste while maintaining the performance required on some of our busiest roads, all within our existing programme budget.”
Connect Hamilton replaced 157 tyres across its vehicle fleet during the past 12 months. The amount of recovered rubber used in the Anglesea Street project is equivalent to nearly 1.7 years of its tyre replacement volume.
Waikato facility supplies rubber
The devulcanised rubber was supplied by Cyclenomics from its new Waikato processing facility.
Road Science says the material undergoes additional processing to break it down into a form that can blend effectively with bitumen.
This differs from conventional crumb rubber, which is made by grinding end-of-life tyres into fine particles.
According to Road Science, crumb rubber can create operational problems because it may not dissolve fully in bitumen. This can contaminate binder tanks, trailers and manufacturing equipment, create blockages in transport and storage systems, and increase fire and fume risks during blending.
Its EcoBlend formulation uses devulcanised rubber to reduce reliance on virgin polymers while retaining the fatigue resistance, rutting performance and durability expected from its FlexiPlus binder range.
Road Science product growth manager Manaf Alshamsi says the industry needs to demonstrate that recycled materials can move beyond limited trials and become part of routine infrastructure projects.
“One of the biggest challenges for the industry is proving circular economy solutions can move beyond pilot projects and into everyday road construction,” Alshamsi says.
“We’re excited to be partnering with Connect Hamilton on this project. It provides another opportunity to demonstrate how recycled tyre materials can be integrated into mainstream road construction while maintaining the performance standards expected from premium polymer-modified binders.”
Road Science product development officer Brennan Barnett-Mullan and the manufacturing team during production of FlexiPlus Bind EcoBlend at the company’s Mount Maunganui bitumen plant.
Performance to be monitored
Hamilton City Council transport director Gordon Naidoo says the project demonstrates the value of the council’s partnership with Downer through the Connect Hamilton contract.
“Together, we’re creating opportunities to trial innovative solutions that improve environmental outcomes while continuing to deliver a safe, reliable and high-performing transport network for Hamilton,” Naidoo says.
“It’s exactly the type of forward-thinking approach our growing city needs, and one that provides lasting value for both ratepayers and future generations.”
The project brings together the council, contractor, recycler and material supplier to test whether recovered tyre rubber can become a viable resource for wider road construction.
Results from the EcoBlend sections will be assessed against the conventional polymer-modified asphalt used across the remainder of the resurfacing site.
The Downer pavement team lays FlexiPlus Bind EcoBlend during the Connect Hamilton trial.
