Approximately 900 of the 1,200 miles of County maintained roads are paved with asphalt. All of the remaining mileage is essentially either dirt or gravel (an insignificant amount of the maintained mileage is paved with concrete). Weathering and excessive traffic loads cause distress to the asphalt pavement. Excessive distress will lead to cracking, potholes and complete deterioration of the pavement. Maintenance activities to minimize these problems and extend the pavement service life include: crack sealing, pothole patching and surface treatments such as overlays, chip seals and slurry seals.
Applying a surface treatment is the most extensive of the pavement maintenance operations. Such treatments include, placing an asphalt overlay, chip seal, or slurry seal. County crews perform some small asphalt overlays. However, chip seals, slurry seals and most asphalt overlays are performed by contract.
Crack sealing is one of the most economical pavement maintenance operations for minimizing pavement distress. Pavement cracks allow moisture to seep into the underlying base material. As this material becomes saturated, support for the overlying pavement is reduced. If significant traffic loads pass over the saturated area, the area will sink and a pothole is likely to form. In colder climates, the water will freeze and expand and actually push up the pavement. Crack sealing helps to prevent these problems by prohibiting surface water from seeping into the base material beneath the pavement.
In the winter months, the pavement is cooler and less flexible, which makes is more susceptible to cracking. Add rain and snow, and this is why there seems to be more problems with potholes in the winter. However, potholes are a year round problem. County maintenance crews repair potholes on a continual basis. The repair is usually only considered temporary until a more complete resurfacing can be performed when funds become available.