Repairing Roads Due to Weather
Much of the work performed by the Coon Rapids Streets Division involves direct maintenance to the city's asphalt surfaced roadways. Minnesota's harsh northern climate is abusive to less traveled neighborhood streets with a relentless cycle of freezing and thawing.
Maintaining City Roads
Many roads which bear a higher traffic load need more frequent care and repairs. As a result, throughout the spring, summer, and fall, Streets Division crews can be found filling and patching potholes, sealing cracks in street pavement, and repaving larger areas of roadways in need of repair. See the current map of street maintenance areas here.
Fog Sealing - What is it?
A fog seal is an application of diluted asphalt emulsion without a cover aggregate “chips”, used to seal and enrich the asphalt pavement surface, seal minor cracks and prevent raveling. An asphalt distributor is normally used to apply the fog seal.
Benefits of a fog seal
Fog sealing has very similar benefits to a seal coat. The purpose of a fog seal is to protect the pavement surface from the deteriorating effects of sun and water. Fog sealing provides a waterproof membrane which slows down the oxidation process and helps the pavement shed water, preventing it from entering the base material. It also provides a clean black surface to aid in snow and ice melting.
The City is using fog sealing in cul-de-sacs to minimize historical problems associated with high volumes of turning movements. During the warmer summer months the seal coat area has a tendency to shift or tear when turning movements occur. Garbage and recycling trucks with their large tandem base can often create these issues along with cars backing out of there driveway and turning their wheels while not moving.
According to the National Center for Pavement Preservation, “a true asphalt rejuvenator is a maltene-based petroleum product which has the ability to absorb or penetrate into an asphaltic concrete pavement and restore those reactive components (maltenes) that have been lost from the asphalt cement binder due to the natural process of oxidation.” Asphalt rejuvenating agents comprise of the same maltene fractions as the asphalt binder and seals and preserves the surface of the pavement.
How does it work?
Asphalt rejuvenating agents have been used for more than 50 years and are proven to add 5-7 years of service life to pavements. They penetrate, rejuvenate and seal the surface by replenishing the lost maltene fraction in the asphalt binder. Maltene is necessary to make the surface durable and flexible. Asphalt rejuvenating agents fluxes with the asphalt binder, restoring the aggregate/asphalt bond. The rejuvenator prevents raveling and stripping and, by densifying the pavement’s surface, it helps address compaction issues, reduces surface permeability, and prevents air and moisture intrusion. It adjusts viscosity and penetration values. It does not contain degreasers, solvents or creosotes.
How is the Asphalt Rejuvenating Agent Applied?
The rejuvenating agent is sprayed like a fog seal. The emulsion is diluted with water to around 60 percent rejuvenation agent. Application rates average between .05-.08 gallons per square yard. It is applied in one pass, has a 20-45 minute cure time, and leaves no surface coating. Then a light coating of sand or limestone screening is applied (1-2 pounds per square yard). The screenings are swept 1-2 days after application. Striping is not compromised and remains visible throughout the application process.
Watch this Video to Learn More
What does seal coating and fog sealing look like in your neighborhood? Find out how the process works.