Why are you working on my brand new road?

It’s a scene playing out throughout the county. Roads that were resurfaced last year, now have work crews on them again. Why is that? It may not be the reason you think.
Based on the comments we’re hearing, some people assume we’re fixing a problem from the original project. That is incorrect. We’re chip sealing, which is the finishing touch that preserves and protects the pavement. It’s a technique we’ve been using for several years, following extensive research about its cost effectiveness and ability to extend the life of the road, and provide a smooth and safer ride.
In recent weeks, we’ve received numerous questions and some concerns about chip sealing. Here are the facts about this process.
The Minnesota Department of Transportation (MnDOT) recently concluded a long term study that measured the benefits of chip sealing. Back in the late 1990s, they divided a recently paved road into 15 sections. For comparison purposes, the first section was not chip sealed. Each year thereafter, MnDOT researchers chip sealed a different section until the entire project was chipped.
Results show an enormous benefit when a road is chip sealed within the first three years, and the earlier the better. It protected the asphalt below from the elements, such as chemicals, salts and – especially – the sun. The chip preserved the flexibility of the asphalt and added 10 to 15 years to the life cycle of the road. Other states, including Montana, Wyoming and South Dakota, have used a same-year chip sealing practice for many years with positive results.
There are approximately 1,500 miles of paved roads under St. Louis County Public Works’ jurisdiction. So as you can imagine, adding 10 to15 years of life to a road is significant. Extending the life of a road by 30 to 50 percent with a chip seal means better driving condition for you for far longer at less cost.
We use a two-part process for chip sealing. There is the initial application of oil and rock, followed by a fog seal. There needs to be a period of time between the initial application and the fog. The aggregate, or small rocks, is continuously compacted by traffic while the oil emulsion cures. Weather conditions such as wind, rain, humidity and sun, affect how long this takes. Next is the fog seal application, which eliminates loose aggregate from that point on. It also assists in reducing damage to the road by snow plows .
We have heard a few concerns about windshield cracks during the chip seal application. We are working with contractors to reduce the likelihood of excess aggregate getting kicked up by tires and hitting windshields. Most important, we ask motorists to slow down and leave more space between vehicles, which minimizes the potential for problems.
Chip sealing is a vital part of our road preservation program, and will continue in the future. As an analogy, think about the effects of sun and weather on the siding of a house. As homeowners, we apply paint or stain to protect against premature deterioration. Very few people would endure the cost of re-siding a house every 20 years, knowing that paint or stain will extend its life. Chip sealing is the paint and the road is the house. We are applying a low cost surface solution to preserve the road below.
Chip sealing is like any preventive maintenance. You may not see the benefit immediately, but over the years these efforts are paid back many times over. We thank you for your patience – both for the process, and for any delays you may encounter in work zones. We continue to make progress in improving St. Louis County’s massive road and bridge transportation system.