Bond Issued for Road and Bridge Projects

The Redwood County Highway Department experienced significantly changing road and bridge conditions throughout 2023.

There have been many questions as to why so many of the paved roadways deteriorated in the manner in which they did this past winter.  Some folks speculate the cause was the oils used in construction or maintenance, others state the manner in which the pavements were constructed or the amount of traffic on a given road.  All of these factors varied with each road that experienced severe surface layer separation, also called delamination.  On the 56 miles of roads that were milled and overlaid this year, the last pavement overlay on these routes was between the years of 1982 to 2001, or 22 to 41 years ago.

In order to understand this better, let’s learn more about how a pavement ages.  As an asphalt pavement ages, the sunlight oxidizes the oils and the pavement structure becomes brittle and unable to stick together.  When it becomes brittle, the pavement can delaminate.  As the pavement ages and oxidizes, it cannot stretch and contract as well with temperature changes.  This causes additional cracking.  Cracks will introduce additional, damaging moisture in and under the pavement layers, causing potholes.  The combined effects of the delamination, cracks and moisture intrusion create a pavement structure that is susceptible to damage from the harsh Minnesota seasons.

In order to help provide a protective layer from the sunlight, asphalt roadways should typically be chip sealed every 7 years, and cracks should be sealed as soon as they develop.  The typical life of an asphalt roadway is 20 years, at which time surface rehabilitation should occur in order to restore the upper layers of the pavement structure.

This information may spur a few more questions, such as why did our roads get up to 41 years old, and what in 2023 was different than previous years.  As you recall, this past winter we experienced multiple freeze-thaw events and multiple rain and ice storms.  When the pavements heated up, water infiltrated through cracks, potholes, and seeped through seal coats wherever holes existed.  As the water re-froze, it degraded the bonds between the oils and aggregates within the pavement structure.  Being the asphalt was already aged, oxidized and weakly holding together, it did not take much traffic impact in order to cause the layers to completely separate and strip apart.  The newer oils in the chip seals held on tightly to the aged pavements below, and pulled up and off the old pavements, taking a thin layer with it.  Additional traffic then caused further pavement delamination, as the highly oxidized and brittle layers below became exposed.

To answer the question, how did our pavements get as old as they are, we need to look at the existing state gas tax funds which pay for most of the road maintenance, rehabilitation and reconstruction work.  With 333 miles of paved roadway, we need to rehabilitate a minimum of 16.7 miles per year of road to ensure each road is overlaid every 20 years.  With $3.4M (Million) per year in State Aid Regular Construction allocation to fund road and bridge construction, and overlays ranging in cost between $129,000 to $646,000 per mile, depending on the complexity of the project and thickness of the new asphalt layer, there is not enough funds to cover the construction needs.  The Highway Department was averaging 13 miles of paving per year, and was quickly falling further behind each consecutive year.  This results in 3.7 additional miles of pavements falling into disrepair each year.   Taken over a 15 year period, this would be 56 miles of our paved roads that have not received necessary rehabilitation.  Ultimately, existing fund sources have not kept up with increasing costs to perform this work.

Redwood County needed to act quickly in order to save the existing pavements.  A $10M bond was sold for use on County Road and Bridge projects, which accounts for 7.7% of the total proposed County levy increase for 2024.  This will be used to pay for the following projects:

  • 2024 CSAH 8 Mill and Overlay from TH 14 to MN 68
  • 2024 CSAH 7 Mill and Overlay from Belview to the North County line
  • 2024 CSAH 10 Mill and Overlay from MN 68 to Vesta
  • 2023 CSAH 2 Mill and Overlay from CSAH 11 to 305th Street
  • 2023 CSAH 3 Mill and Overlay from Morgan to the East County line
  • 2023 CSAH 4 Mill and Overlay from CSAH 6 to TH 71
  • 2023 CSAH 5 Mill and Overlay from Walnut Grove to CR 52
  • 2023 CSAH 7 Mill and Overlay from Seaforth to MN 19
  • 2023 CSAH 10 Mill and Overlay from TH 14 to the South County line
  • 2023 CSAH 12 Mill and Overlay from MN 19 to CSAH 7
  • 2023 CSAH 16 Mill and Overlay from CSAH 1 to MN 68
  • 2023 CSAH 45 Mill and Overlay from the South County line to CSAH 10
  • 2024 County Road 78 Embankment Stabilization by Plum Creek Park
  • 2023 County Road 52 Bridge/Box Culvert 93246 Replacement (local costs only)
  • 2023 County Road 68 Bridge/Box Culvert 89893 Replacement (local costs only)
  • 2024 County Road 51 Bridge 64503 Replacement (local costs only)

Over the next five years, we will complete an additional 77 miles of pavement rehabilitation projects, with $25.7M in funding already secured.  Despite all of the work that will be done over the next five years, there is still 49 miles of roadway needing rehabilitation which no funding currently exists for.   This accounts for an additional $17.5M of unfunded work, despite our continued efforts to apply for additional State and Federal funds.  In addition, there are 73 bridges needing replacement over the next ten years at a cost of $54M, in which we will pursue State and Federal Bridge bonds to cover a majority of the costs.

The Highway Department will continue to plan upcoming projects based on available funding. Our five year plan on our webpage is intended to be flexible, recognizing road and bridge priorities may shift due to rapid changes in highway and bridge conditions, public input, goals, priorities and budget constraints.  If you ever have a question regarding our work at the highway department, please do not hesitate to call our office at (507) 637-4056.

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