Minnesota’s County Road No. 7 reconstructed to support 10-ton traffic

Minnesota’s Kandiyohi County Road No. 7 was in need of reconstruction.

“This segment of the grading and bituminous surfacing project was projected to receive a lot of heavy truck traffic with a projected [average daily traffic] of 883,” said Assistant County Engineer Ray Krossman.

The original structure design was 9 in. of MN Class 5 aggregate base and 5.5 in. of bituminous surface to carry 10-ton traffic. The goal was to eliminate 1.5 in. of the bituminous surfacing by using Team Laboratory Chemical Corp.’s Base One Aggregate Base Stabilizer to increase the Granular Equivalency (GE) value of the aggregate base material, maintain a 10-ton design, and have a cost savings.

The final design approach was to grade the project in 2010 with 9 in. of MN Class 5 aggregate base and stabilize the top 4 in. of the base material.

“During the grading project we encountered poorer soil conditions than expected in three areas of the project,” said Krossman. Braun Intertec, an independent testing company, conducted deflection testing after the application of the base stabilizer and determined that the three problem areas would require more than 4 in. of bituminous.

In 2011 Kandiyohi County placed an additional 3 in. of stabilized aggregate base material in the three weak areas and 4 in. of bituminous on the entire 5.5-mile project.

Braun Intertec conducted deflection testing on the final surface resulting in 10-ton capacity for the entire road.

After comparing the original structure design cost to the final design cost, Kandiyohi County had a cost savings of $190,000 on the project.

Related Articles

Two civil engineers—Thomas Telford and John Loudon McAdam—are credited with building the first modern roads in the 1800s. Telford would later improve…
January 04, 2022
Oklahoma’s interstate construction history provides an inherent experiment allowing the comparison of asphalt versus concrete highway surface…
January 04, 2022
Study ranks state highway systems by road conditions, safety, and cost-effectiveness
Image: Reason Foundation
Reason Foundation today released its Annual Highway Report, which measures the condition and cost-effectiveness of state-controlled highways in 13…
November 18, 2021
How the texture of a pavement surface contributes to the tire-pavement friction
Image: Hossein Roshani
Proper tire-pavement interaction is essential for the safety of motorists. Pavement surface texture is a major contributing factor to tire–pavement…
October 05, 2021
expand_less