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.
Surface Treatments
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
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.
Pothole Patching
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.
The Department utilizes a computerized Pavement Management System
(PMS) to prioritize which roads receive a surface treatment. The PMS
assists the Public Works engineering staff in evaluating, tracking, and
ranking pavement conditions based upon field inspections. The major
roads are inspected biannually and all other paved roads every 4 years.
Which roads are overlaid, chip sealed, or slurry sealed is dependent
upon the PMS ranking, traffic volumes, and available funding