MnDOT has a flaky problem with the Mendota Bridge

Department of Transportation crews are out scraping away the thin layer of asphalt and aggregate that has come loose on the Mendota Bridge.

Friday was not the first time they have had to do that. And it probably won't be the last.

The epoxy chip seal put down to make the driving surface less slippery and prevent water from seeping below the concrete has been peeling away bit by bit. Over the past two summers, the slow-motion deterioration has grown to include hundreds of square feet of exposed concrete. And that has forced MnDOT to go out several times to remove sections of the crumbling material to prevent it from being kicked up and hitting cars, bicyclists or pedestrians passing by on an adjacent trail.

MnDOT says there have not been any serious injuries or damage to vehicles or the bridge itself. But one Drive reader said he was hit by flying overlay while biking across the 4,100-foot span over the Minnesota River linking Mendota Heights and the Fort Snelling area.

Another reader e-mailed that he noticed the flaking last year and "14 months later, it's no better." Sad to say, it may not get better anytime soon.

Contractor Poly-Carb put down the surface in 2011, and it's a surface that should have a long life, at least longer than seven years, said MnDOT spokeswoman Kirsten Klein.

For some reason, the product did not adhere correctly, Klein said, and MnDOT has been trying pursue a warranty on the work.

It's been tricky because Poly-Carb has changed hands. The firm was owned by the Dow Chemical Co. at the time the chip seal was put down, but the company was later sold to Olin Corp. The Drive asked Olin if it was aware of the issue.

"While Olin acquired the Poly-Carb business from Dow in 2015, the work performed and subsequent warranty is through Dow," Olin said in a statement.

Jarrod Erpelding, a spokesman with Dow corporate affairs, said his company "has discussed the warranty with MnDOT and is investigating."

MnDOT says it is continuing to see what, if any, options it has to get the work redone and put its warranty to work. But this looks like a battle that may end up in court, with drivers left navigating a bridge that continues to flake off.

Just as northwest metro drivers breathe a sigh of relief now that all lanes on Hwy. 169 through Brooklyn Park and Champlin have reopened, here comes another potential traffic tangler.

Starting Monday, MnDOT will begin installing a center concrete median on Hwy. 610 over the County Road 81 and BNSF Railroad tunnel near Elm Creek Boulevard in Maple Grove. To do that, MnDOT will close the inside lane of eastbound Hwy. 610 for about 30 days. That may cause traffic backups on I-94, said spokesman Kent Barnard.

The barrier was part of the original Hwy. 610 project that did not get completed when the highway was built.

Barnard called the work "preventative" and said there has not been a rash of crashes on the highway. "But it needs to be done," he said.

Follow news about traffic and commuting at The Drive on startribune.com. Got traffic or transportation questions, or story ideas? E-mail drive@startribune.com, tweet @stribdrive or call Tim Harlow at 612-673-7768.