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NRI Industries of Toronto Canada has been getting together with community leaders and organizations this past year, to show people how versatile rubber can be.

For example, NRI Industries joined Toronto artist Noel Harding by donating over 5,000 pounds of shredded rubber to the Elevated Wetlands project near Toronto's Don Valley Parkway.

In April of this year, NRI's Tire Recycling Unit in Michigan helped the people of Detroit get rid of scrap tires in their neighborhoods and put them to use in a local playground. Just a couple of months earlier, the company worked with members of Toronto's Balmy Beach Lawn Bowling Club (BBLBC) to help fulfill an innovative idea for their bowling greens.

"People are realizing that recycled rubber is actually a valuable and versatility resource that can be used in everything from art, to playgrounds and sports areas,"
Paul Grunthal , NRI Technical Specialist said.

Building public perception
The Elevated Wetlands is the work of international artist Noel Harding. Sponsored by the Canadian Plastics Industry Association, the project combines plastics and art by focusing on the usefulness, resourcefulness and aesthetics of recycled materials. The Elevated Wetlands are adjacent to the Don Valley Parkway, near Don Mills Road, and situated in Taylor Creek Park, Ontario.

The structures use recycled materials as a growing medium for native plants. Solar powered pumps move water from the Don River up into the planters and like a wetland, the vegetation in the structure will help cleanse the water as it moves through the plants and flows back into the Don. NRI's crumb rubber will act as mulch, covering the top 10cm of every planter adding to both the aesthetics and function of the growing mediums.

Grassroots effort paying off
Volunteers from Motor City Blight Busters (MCBB) and industry banded together to collect tires during Detroit City's Clean Sweep Program. "This is one of the finest examples of public-private partnering at work," said Mayor Dennis Archer.

NRI's Michigan facility shredded the over 15,000 tires recovered and gave 7,000 pounds of the granulated rubber to MCBB. The rubber crumb was mixed with urethane to make a resilient and safe playing surface for the new 2,500 square foot basketball court.

Toronto's BBLBC called NRI about using shredded tire rubber around the perimeter of their lawn bowling greens. "Conventional pea gravel can damage sports equipment and green mowers," Grunthal said "so we suggested replacing the gravel with rubber crumb."

After looking at several sizes and shapes of granulated rubber we discovered that a semiporous liner made from recycled rubber crumb would actually be more effective and economical that crumb itself." Over 800 feet of donated material was installed and Lawn Bowling Championships will be played at Balmy Beach next July, Grunthal said.

Research is key to market growth
NRI is also investigating the use of crumb rubber as a soil supplement for compaction control in sports turf as part of a research project at Guelph University near Ontario.

Reporting on the progress of the research at Rubber Recycling '98, a conference sponsored by the Rubber Association of Canada, Grunthal said that field tests are showing the addition of approximately 15-20 percent crumb rubber by total dry mass will enhance turfgrass growth and playability of fine textured loam soils. The field test also suggested that 15-20 percent rubber crumb significantly reduced soil surface hardness. Field test results also showed that soil containing more than 15 percent crumb will experience decreased soil shear strength. In addition, rubber crumb decreased soil water content in the root zone, which researchers say may result in less damage to perennial ryegrass from "winter kill." Crumb rubber also increased the concentration of zinc in grass tissue to non-toxic levels, according to the field test data.

Analysis of leachate collected from treatments containing rubber crumb indicated the admixtures posed little environmental risk, Grunthal said. Concentrations of metals in effluent were far below Ontario's Drinking Water Objectives (ODWO). Slightly elevated concentrations of metals in leachate from rubber crumb admixtures were generally negated by the incorporation of peat moss or lime.

Also, while levels of volatile organics and extractable compounds were sometimes slightly higher than interim Provincial Water Quality Objectives and ODWO limits were neither statistically significant nor were they directly attributed to the amount of rubber crumb in the admixture. Nutrient analysis of turfgrass tissue indicated that rubber crumb did not produce element concentrations toxic to turfgrass.

"Under these experimental conditions, rubber crumb does not appear to be detrimental to the environment," Grunthal said. "In addition, rubber crumb is a more efficient inorganic soil amendment than sand and much less toxic that sewage sludge," he said. Rubber crumb may also be used to improve zinc deficient soils, soils with poor structure, and soils with poor drainage characteristics. It is also longer lasting and less expensive than peat, Grunthal said.

The company is looking at applications for rubber crumb-enhanced turfgrass in sports fields, and in high traffic areas in public parks and other recreational areas.

"This product represents on e of our newest marketing areas," Grunthal said. "As with our other products, we've invested in both science and technology to develop this product application for crumb rubber...its part of our commitment to finding more uses for recycled rubber."

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