By Roz Kohls
DASSEL, MN Meeker County Board of Commissioners decided Tuesday to authorize the third and final layer of pavement on Meeker County State Aid Highway 18, south of Dassel, despite not knowing for sure what went wrong with the second layer in the $2.2 million project.
The final layer is needed now, so the 7.5-mile road has enough strength to survive freezing and thawing in the spring, said County Highway Engineer Ron Mortensen. Also, farmers have started harvesting beans. Soon they will be harvesting corn also, and the heavy trucks carrying those loads will need a strong road this fall, he said.
At the end of August, the contractor, Knife River of Sauk Rapids, discovered “shoving,” or road failure, in the second layer of bituminous. It appeared the road slid off its bed, causing cracks, some as long as a yard, in 25 percent of the second 1.5-inch layer. What caused the failure has been a mystery.
“My people are about ready to pull their hair out,” Mortensen said.
The contractor surmised the road failure was caused by underground springs, although county engineers couldn’t find enough water to warrant the $250,000 worth of damage to the road, Mortensen said.
Some MnDOT engineers said CSAH 18 had a weak roadbed, but strength test results the county received Sept. 8 showed the roadbed was not the problem, according to County Administrator Paul Virnig.
The materials and operations Knife River used passed every test and met specifications in every area.
“We cannot find out what they are doing different,” Mortensen said.
County Commissioner Dave Gabrielson said he was sure the damage was caused by heavy construction trucks and overloaded trucks that drove on the fresh surface within hours of when it was put down. There is no direct evidence that heavy trucks caused the road to move either, Mortensen said.
Trucks that are 10 percent overloaded, however, cause 90 percent of the damage to roads, he agreed.
For the final layer, though, Mortensen said the county engineers and Knife River have agreed to keep the big trucks off of it until the layer is completely cool. The contractor also will use steel rollers instead of pneumatic rollers, and change other aspects of the operations.
Knife River used the same materials in the repair work as it did in the second layer, and it seems to be holding, despite the increased farm activity.
Gabrielson said he was concerned if the county recommended changing operations for the third and final layer, and the road “shoves” again, the county will have the “monkey on its back,” instead of the contractor. He pointed out that the contractor’s materials and methods passed every test.
County board members agreed, however, that the county will not pay for the $250,000 repair on the second layer until it has more information on what went wrong.
In other highway business, the county board hired Gayle Flemming as a temporary full-time maintenance foreperson in the Rosendale shop until April 30, 2009.
In addition, the county highway department received a notice from Rick Kjonaas of the MnDOT Office of State Aid that Minnesotans are buying fewer gallons of gasoline, so the gasoline tax won’t generate as much revenue as Kjonaas expected. Kjonaas warned highway engineers to expect 5 percent less than what they had planned from the state for projects in 2010 and beyond.
This decrease in funding might affect a 3.4-mile CSAH 27 project near Kingston in 2010, Mortensen pointed out.