Additive produces solid base

When reconstructing a 7-mile section of roadway, the Meeker County, Minn., Highway Department reduced the cost and material needed for the project by adding a chemical aggregate base stabilizer.

CSAH 15 in Meeker County was last rebuilt in the 1950s. Meeker County’s assistant engineer, Mark Spies, stated that with high maintenance costs and high traffic count, it was time for this road to be reconstructed. The road encountered existing subgrade failure. and the bituminous over the wetland areas was continually sinking, causing extra maintenance.

The existing road had slopes that were too steep (in slope and back slope) and the shoulder was too narrow for any type of mill-and-overlay project. It was decided to complete a total regrade on this project and add Team Laboratory Chemical Corp.’s Base One Aggregate Base Stabilizer for additional strength. With an early summer letting, the goal was to complete the entire 7 miles of road in one summer.

The road was constructed with a full grading crew. The existing bituminous was milled off and used for interim surfacing while the road was under construction. A 2-ft sub cut was performed throughout most of the project. A lightweight fill was used throughout the wetland areas. The materials for the road fill came from existing clay in ditch cuts, as well as borrow areas.

A MN Class 5 aggregate base was used over the top of the MN Class 7 millings. The Class 5 aggregate base was placed to a depth of 4 in. and was treated with the aggregate base stabilizer. With the incorporation of the aggregate base stabilizer, it was decided that 2 in. of the base material could be eliminated.

A bituminous surface consisting of 3 in. of base course and 3 in. of wear course was added. The lines were painted and the project was completed.

According to Spies, the end results were greatly enhanced by the addition of the Base One for a variety of reasons:

The county saved approximately $140,000 by adding the aggregate base stabilizer and being able to eliminate 2 in. of MN Class 5 due to the strength gained by its addition.

The weak areas found by the gravel trucks during the hauling of the aggregate base were not evident when the bituminous trucks hauled the hot mix across the project’s stabilized base.

Minimal density failures on the newly placed bituminous made for a better overall project and resulted in the contractor’s receiving performance bonuses for rideability and density.

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