The public works department at Ramsey County, MN promised the city of Shoreview, a suburb of St. Paul, that a repair of 300-feet of Lexington Ave. wouldn’t take more than five days last summer. The road has roughly 8,000 vehicles each day accessing adjacent businesses and neighborhoods. Five days would be a long time for some of the impacted people.

Jerry Auge, the general supervisor of maintenance and construction for the county, didn’t anticipate the extra challenge of a six-inch rain during construction. But because the county chose TDA (Tire Derived Aggregate) to use as lightweight fill, the water wasn’t as big of a hassle. “The rain slowed us up a little, but with the tires, the water didn’t affect us that much,” Auge said. “We pumped the area dry. We didn’t have to dry out the tires.”

Other types of fill have been used on different county projects. On this job, when TDA was compared to alternatives, like dirt, wood chips, or styro foam blocks, TDA came out ahead. TDA is lightweight, cost effective and less labor intensive than some of the alternatives. Auge had worked with TDA on another county project and knew the lightweight factor was important for the Lexington Avenue job.

The problem on Lexington was the road had settled between 2.5 to 3 feet. When the road was built roughly 10 years earlier, conflicts with utilities stopped the county from dealing with the boggy soil under the road. The road began to sink within two years of construction. Now, when the county wanted to fix the road, utilities were still an issue. The solution was to excavate two feet of dirt off the top of the roadbed and replace it with three feet, or 1,500 cubic yards, of TDA and build the road back up.

“Had we used dirt, chances are the road would have settled again because of the weight added to the top,” Auge said. “With lightweight fill, we’re able to keep the weight off.”

…and keep 8,000 vehicles moving every day.