Features Heavy Equipment Roads & Paving Technology
Manitoba association is putting the rubber to the road – literally

Asphalt experimentation has exploded in recent years, with everything from tree pulp to olive oil being tested for their roadbuilding abilities. A classic among these alternatives, however, is rubber-modified asphalt (RMA), a longstanding material solution that’s gaining traction in Central Canada thanks to advocacy and research efforts from Tire Stewardship Manitoba (TSM).

TSM’s work has led to every available end-of-life tire in the province now being recycled and transformed into construction material alternatives including aggregate, crumb rubber and fabricated and manufactured products, including rubber-modified asphalt (RMA) and tire-derived aggregate (TDA) to support provincial infrastructure and roads.

“Recycled tires not only make better roads, but they are also better for the environment and better for Manitoba,” said TSM CEO Brett Eckstein. “Tire-derived aggregate has quietly been strengthening Manitoba’s infrastructure for decades.”

In addition to building roads more suited to handle the specific weather wear experienced by the province, Manitoba’s tire recycling initiatives have created more than 50 full-time jobs and $10 million in direct economic activity, said Eckstein. 

Tire-derived Aggregates On a Roll
RMA was first used in the 1960s as a paving solution in Phoenix, Arizona, and has since grown in use across the United States, including extensive use in California, Arizona, Florida and Texas. This solution reached Canada in the early 2000s, with testing primarily occurring across Alberta, British Columbia, Ontario and Saskatchewan.

RMA is mainly used in the construction of public roads and highways, community sidewalks, bike paths, commercial parking lots and residential driveways, and offers several benefits, including lowered maintenance costs, reduced pavement thickness, lower traffic noise and the diversion of old tires from landfills, Eckstein said. 

The volume of diverted tires is significant: for each ton of TDA produced, approximately 100 tires are kept out of landfills. TDA’s higher permeability, thermal conductivity, shear strength, compressibility, combined with its lower overall unit weight, makes it a cost-effective substitute for conventional aggregate materials such as stone, gravel or soil. 

Passenger, light-truck and off-the-road tires (OTR) are most commonly used in the recycling process, with Eckstein sharing that OTR tires are preferred due to their produced TDA sharing a similar size to traditional aggregate. RMA is produced by mixing recycled crumb rubber from these scrap tires into conventional asphalt mixes.

While there have been limited advances beyond the testing stages in Canada’s use of these solutions, Eckstein believes that supporting the research and education needed to dial in the best practices for these materials will increase their performance potential and in turn, their overall usage.

“Under the right construction practices such as accurate mix design, and with appropriate training for contractors and municipalities, RMA [used in Canada] should show comparable performance to that of the United States,” he said. 

Stewarding Better Roads
As TSM’s leader, Eckstein oversees a number of advocacy, research and grant initiatives and partnerships across the province’s infrastructure sector that have advanced the usage of TDA and RMA in Manitoba. 

Replacing the provincial government’s Tire Stewardship Board in 2008, TSM is a not-for-profit corporation formed to both protect the environment and promote economic benefit through managing the province’s end-of-life tire recycling program on behalf of tire sellers across Manitoba.

According to Eckstein, Manitoba has two tire recyclers that focus on its local markets, Reliable Tire Recycling (RTR) and the Engineered Rubber Aggregate Corporation (ERA). Between each company, a total of two million tires are recycled each year, a near 50 per cent growth compared to the provincial volume a decade ago. 

In addition to its promotion of the best practices for end-of-life tire management across the province, TSM also contributes routine funding and research into the disposition and innovative use of end-of-life tires, including a life cycle assessment from 2017 to 2023 that looked to estimate the environmental performance of this solution in the province.
This research looked to compare competing products and materials whose impacts could be avoided through the use of tire-derived materials with the impacts of recycled tire material itself.

“The study found that Manitoba’s short overall transport distances and clean electricity grid produce relatively small impacts and a net environmental benefit for tire recycling in the province, and TSM intends to periodically update this study and report its findings,” Eckstein said. 

Fit For Manitoba
TSM’s success in promoting the use of TDA material in road construction comes largely from the unique climate of the province, and the infrastructure demands it creates being particularly suited for the benefits presented by TDA.

“Our extreme climate, poor drainage, and soil type create the perfect conditions on Manitoba’s municipal roads for frost heaving due to high ground water level close to the surface, fine soils that ‘wick’ the moisture into the roadbed and temperatures cold enough to cause ‘frost lenses’ to form in the roadbed. The eventual thaw causes the road to break down,” said Eckstein. 

He explained that current efforts by the organization focus on promoting the effective use and practices of TDA across the province’s infrastructure as the first step toward its inclusion as a widespread solution in roadbuilding.

“TSM has been working with stakeholders in roadbuilding and the province to use the material more broadly in infrastructure projects, and continues to invest in research studies to verify support for tire-derived products in all potential uses,” said Eckstein. “[We’re] working towards tire-derived aggregate as a commonly-used recycled material in Manitoba’s infrastructure, and as the ideal solution to road building, repairs, and quarry rehabilitation efforts.”

Eckstein cited numerous roadbuilding projects that have made use of RMA and tire-derived materials across the province, including the rural municipalities of La Broquerie, Springfield, West Interlake, Hamiota, Grahamdale, Lac du Bonnet, Gimli and the Town of Springfield. 

Perhaps the most high-profile of those he shared, however, was a large embankment project in the province’s capital. The project leveraged the insulating properties of TDA as a shield against Manitoba’s cold weather, with this property adding to TDA’s attractiveness for the area’s infrastructure solutions. 

“In Winnipeg, TDA was used to build a 305-meter-long embankment above soft ground to act as a subgrade thermal insulator to limit frost penetration and prevent road damage,” he explained. ”A layer of TDA under a road can prevent the subgrade soils in northern climates from freezing in places where they release excess water during spring, and its high permeability allows water to drain from beneath the roads and reduces the chance of damage to road surfaces.”

Other types of infrastructure construction projects that Eckstein believes can benefit from TDA’s insulating properties, lightweight nature and high permeability include building foundations, septic system construction and light-rail projects.

Beyond research and advocacy, TSM’s support for TDA’s use across the province’s infrastructure construction sector also takes the form of funding through their longstanding Community Rubber Aggregate Grant. 

“For a number of years, TSM has continued to offer a Community Rubber Aggregate Grant that provides funding for the use of recycled projects made from Tire Derived Aggregate delivered by Manitoba communities and non-profit organizations,” Eckstein explained. 

Through the grant, 50 per cent of project costs up to $20,000 is provided to communities and non-profit organizations for their use of recycled tire aggregate. This grant is commonly put toward road restoration projects in the province, he shared, with 2023’s funding going to four rural road repair projects.