Winter, 2006
By Ohio Asphalt Magazine

Lucas County is testing the use of ground tire rubber (GTR) in asphalt binder on a section of Toledo’s King Road.

In Toledo what goes around comes around, especially when you’re talking about rubber tires.

Last October, Lucas County had the northern portion of King Road coated with an asphalt blend containing ground tire rubber (GTR). Along with the Lucas County Engineer’s Office, other FPO members involved in the eight-tenths-of-a-mile demonstration project were Gerken Paving, of Napoleon, and Seneca Petroleum Company, of Crestwood, Ill. While blending tire rubber into the asphalt binder increased the price of the project by 11 percent, the Lucas County Engineer’s Department wanted to experiment with the ground tire additive. “We decided to do it, to give it a try and see if it is better, like (the manufacturer) claims,” said Lucas County Engineer Keith Early in a Toledo Blade article. “We will look at it over the winter then decide if we want to pursue a grant.”

Typically for its surfaces, Lucas County uses high-performance asphalt modified with polymers. The performance of GTR as an asphalt additive is marketed like other forms of polymer modifications, which includes more durable pavements that resist deformation and cracking. It’s also believed GTR reduces noise caused by vehicle tires. Maintenance departments are watching to see if the GTR additive keeps the asphalt blacker longer, which keeps the pavement warmer and may reduce the amount of road salt needed in the winter. The equivalence of 2,000 ground up tires were included in the more than 1,000 tons of asphalt used on the King Road project.

“It’s definitely a different material, although people driving over it won’t know the difference,” Early said. The demo project involved a one-inch Smoothseal (ODOT Item 424, fine-graded polymer asphalt concrete) application over a 1/2-inch conventional leveling course (ODOT 441, Type 1). Gerken Paving, which has much experience in producing and placing Smoothseal, used an aggregate blend of #8, #9 and #10 and natural sand to make the strict gradation that is required for Smoothseal, Type B.

For the King Road Project, Seneca Petroleum was chosen because it produces an asphalt binder that is modified with reclaimed tire rubber. The Seneca Petroleum binder (PG76-22 GTR) is produced by modifying the base asphalt with ground tire rubber and Vestenamer reactive polymer supplied by Modified Asphalt Solutions of Macon, Mo.

Like most solid waste management districts, Lucas County and the city of Toledo are trying to come up with alternatives to its tire disposal. In 2004, it cost $76,600 to dispose of 41,500 tires in Lucas County. Because GTR can be used as asphalt binder similar to what is found in polymer modified asphalt (ODOT PG76-22M specification or PG64-22 binder with the addition of 5 percent Styrene Butadiene Rubber (SBR) polymer) needed in the application of Smoothseal, a landfill alternative may have been found.

“Right now, tires are used in landfills and sometimes as mulch, or ground up for playgrounds,” said Jim Walters, manager of the Lucas County Solid Waste Management District. “But if you look at it overall, how much of those tires are really getting used. There’s a little more cost incurred (with this asphalt). But if it does what it says, it’s worth the investment.”