The Pettis County Commission has come up with an innovative new material mixture for chip-and-seal that also helps the environment.
States across the U.S. are trying to figure out ways to recycle old rubber tires, but so far few ideas have been created or successful. Pettis County Western Commissioner Jim Marcum pitched the idea of using those rubber tires as a chip-and-seal product on roads, and after gaining a grant from the Missouri Department of Natural Resources, testing began.
“This material is something I have thought about for several years, even in my construction work,” Marcum said. “There’s just so much rubber nobody has anything to do with it, and I’ve always thought you cant finance this stuff with a private company, but we applied for a grant from DNR. DNR, first thing they said was they’ve been trying rubber for several years and it doesn’t work very well. (We asked), have you used it as an aggregate, which means the actual rock itself. We perked up their interest on that.”
Pettis County teamed up with Missouri S&T in Rolla to conduct lab testing over the last year and a half for the product. The tires are turned into chip-sized pieces to match the creek rock and limestone typically used for chip-and-seal, a process that helps extend the life of a road. The research team tried multiple variations of rocks and oil to make the material work.
After lab testing, the Pettis County Road Department began field testing this week, applying the two mixtures in separate places on a portion of Griessen Road on Tuesday morning.
“The recommendation was to try the 25 percent rubber with our rock first. That worked really well, mixing 25 percent of that in with our regular rock, it seemed like it laid well, it stuck well,” Marcum said. “Then we tried the 100 percent (rubber), that was actually the best for a car coming to a stop on. It’s going to take some different equipment to do the 100 percent rubber because it’s so much lighter than regular rock.”
The lead professor from Missouri S&T working on the project will be in Pettis County next week to look at Griessen Road. The research team and Pettis County will observe the road through the spring, watching how it reacts to a number of situations, such as freezing and thawing, cold and warm temperatures, traffic, and snow plows.
Marcum said they took advantage of the warm weather this week to begin field testing. If not, they would’ve had to wait until next year so they could observe the material during the winter season. He added that he’d like to test a 50/50 mix next year if the current tests perform well. In the first few days, so far results are “positive” and the commission “is pleased,” Marcum said.
They will also be testing how long the material will last. Pettis County Eastern Commissioner Hampy said chip-seal normally lasts three to five years, depending on how good the road’s base is. It’s normally not meant to be a long-term solution to fix a road, but they’re not sure how this new material will hold up yet.
Marcum said there are several advantages to using rubber for roads.
“Salt won’t eat on rubber where it will etch a rock,” Marcum said. “There’s so many advantages to it, plus keeping all these tires out of the landfill.”
Hampy said Pettis County is the only county they know of in the country testing this type of material. All eyes are on Pettis County now, including MoDOT and other state agencies, to see if the product is viable.
“It’s a new program Pettis County is leading the charge on, trying to help solid waste because right now, yes, the landfill would like a few slabs of rubber to put down as the bottom of the landfill, but other than that I know we have a lot of tires piling up and we don’t have a use,” Hampy said. “… Everyone’s looking for an option — this may be one.”
Nicole Cooke can be reached at 660-530-0138 or on Twitter @NicoleRCooke.