By Brian Johnson
Dolan Media Newswires
Minneapolis — An eastbound stretch of Interstate 90 in southern Minnesota is showing its age, but the bumpiness should be fixed by this time next year.
I-90’s heavily traveled eight-mile stretch between Highway 43 and Highway 76 will be repaved next summer, and the finished product is expected to last at least 30 years. I-90 was built between 1965 and 1970.
Last week, PCIRoads LLC, St. Michael, Minn., emerged as the apparent low bidder for the Winona-area project with an $8.67 million bid that was slightly less than the Minnesota Department of Transportation’s $9 million estimate.
The project, scheduled from May through September, calls for an unbonded concrete overlay. Crews will use about 1.5 inches of bituminous as a barrier between the old concrete and the new concrete.
It’s important to have that barrier because if the old concrete was allowed to bond with the new, the surface would absorb all the cracks and holes from the old concrete, said Kristin Kammueller, community relations coordinator for MnDOT District 6.
Moreover, it’s cheaper to do the work this way than to build an entirely new road. And, in theory at least, it makes for a stronger road because the old concrete acts as a durable base.
Even so, MnDOT started using unbonded concrete in the early 1980s, which isn’t enough time to prove the theory.
“You should be able to get longer life out of the concrete,” Kammueller said, “as opposed to if we were going in there and tearing up the old concrete and starting from scratch.”
The downside is that it’s more expensive than a typical bituminous overlay. A similar stretch of westbound I-90 was completed as a bituminous project for about $3.2 million.
With a 30- to 40-year life expectancy, the road is expected to last longer than a bituminous project, which is considered a 10- to 20-year fix.
One advantage of going with concrete on the eastbound lanes is they should still be going strong when the westbound starts to deteriorate.
“We won’t have to do both westbound and eastbound at the same time,” Kammueller said. “It’s a good planning thing.”
The project is a continuation of eastbound I-90 concrete overlay from Highway 74 to Highway 43. PCIRoads completed that $15.3 million project in August.
I-90 sees 14,000 to 15,000 vehicles per day in the project area.