A 6-mile gravel segment of Becker County, Minn., CSAH No. 35 had very high annual road-maintenance costs due to several resorts, logging trucks and an ADT of 280. The road surface was very rough due to wash boarding, along with a severe dust problem. To solve the problem the county looked at a couple of options.
To construct a roadway with a 2-in. bituminous surface for this 6-mile segment at current-day costs it would have cost the county $1,140,000, or $190,000 per mile.
In order to get the benefits of bituminous without the cost, the county decided to stabilize the base material with Team Laboratory’s Base One Aggregate Base Stabilizer, then place a less expensive otta seal and chip seal surface treatment on the roadway.
The stabilizer was used in the base material to ensure that the county obtained a good strong aggregate base and the proper support so it would stand up to the heavy traffic load.
The in-place aggregate material was tested to determine what type of additional MN CL-5 was needed to make a good aggregate base. Four inches of a modified MN CL-5 was hauled in.
The material was windrowed and mixed with the in-place CL-5 material. The material was laid down in 2-in. lifts, applying the base stabilizer and water mix to each lift and compacted to optimum density. A double otta seal surface treatment was applied. The surface was chip-sealed the following year.
By using the base stabilization along with the otta seal and chip seal surface treatment, the county was able to construct (at current day costs) the 6-mile segment for $480,000, or $80,000 per mile. This was a savings to the county of $660,000 on the project, or $110,000 per mile, over a 2-in. bituminous surface while still obtaining the benefits of bituminous.
The 6-mile project was constructed in segments. Each year’s section has performed very well with the truck traffic during each construction period, logging and resort traffic.