What is a "Chipseal"?
Chipsealing is one of the pavement preservation methods which the Josephine County Public Works Division uses for road maintenance. Chipsealing, which may have been done recently on a road in your area is spread on approximately 30 miles of county-maintained roads each year.
How do we determine what roads will be chipsealed?
Operations uses road evaluation programs to determine which roads will be chipsealed.
How does a Chipseal work?
Generally, the process involves cleaning and filling individual cracks in the road surface with hot liquid asphalt. The entire paved surface is then sprayed with an emulsified liquid asphalt at a rate of approximately one-half gallon of liquid asphalt per square yard. Next, approximately 27 pounds per square yard of aggregate chips are spread across the entire surface. The aggregate chips are pressed into the emulsified liquid asphalt with a power roller, before the emulsified liquid asphalt cools to a semi-solid state, holding the aggregate chips for a new wearing surface.
Does a Chipseal help the road?
This process preserves the road by penetrating storm water from getting into cracks in the road surface. Moisture can damage the road foundation. The new surface also provides a better skid resistant roadway for motorists.
How often are roads covered with Chipseals?
Our ten year history shows in an average year, Chipseals are applied to about 7-10 percent of Josephine County's total of 570 miles of county-maintained roads. It is only through the periodic use of Chipsealing that the Public Works Division can prolong the life of an asphalt road, and avoid the higher cost of an overlay. The work is usually done in the summer. The warmer weather is necessary for the asphalt to cure properly and take a firm grip on the rock chips.
How long will a Chipseal last?
Eventually, a new hot asphalt concrete overlay is required on some roads. When a hot asphalt concrete overlay is scheduled, the road is often straightened and widened where it is feasible and cost-effective. Most hot asphalt overlays are applied approximately 2" thick. A Chipseal can last from 5 to 7 years or more, depending on different factors. Factors such as average daily traffic counts, types of weights a road will experience (heavy trucks vs. passenger vehicles), and the classification of road (arterial, collector, or residential) will determine how long a Chipseal may last.
Do other counties Chipseal their roads?
Chipseals are used by virtually every county and state highway department in the United States as a cost-effective alternative to asphalt concrete overlays.
Why don't we pave all the roads with asphalt concrete?
Josephine County cannot afford to overlay all the roads in its jurisdiction with hot asphalt concrete without a long-term, significant increase in revenue. The cost of a hot asphalt concrete overlay compared to a Chipseal is approximately four times more expensive.
The Public Works Department may contract for asphalt concrete overlays on some of Josephine County's more significant highways and will also do hot asphalt concrete repairs on isolated problem areas or minor segments of roads.
How will I know if my road is going to be Chipsealed?
Notification is sent to all adjacent property owners and other property owners who could be expected to use the roadway. Before the Chipsealing process begins, informational signs are placed on the roadways to inform the public of the start date for Chipsealing.
What is it Asphalt Overlay?
A pavement overlay is the application of a layer of hot, bituminous paving to an existing paved residential driveway, commercial parking lot, or road that has deteriorated from years of wear from traffic and the environment.
Why is it done?
An overlay adds structural capacity, riding comfort and skid resistance, which adds to the appearance and safety of the road. Smooth road surfaces also decrease vehicle maintenance costs and improve fuel economy. Pavement overlays help reduce traffic noise, which is important in urban developments. Pavement deterioration is cumulative. Pavements generally deteriorate at an ever increasing rate. Factors including weather, traffic impacts, frequency of maintenance, etc., all contribute to an overlay's longevity. Routine maintenance is essential to minimize long term costs. An overlay can extend the life of a road and delay the time in which reconstruction is necessary. When a paved road, parking lot, or residential driveway reaches about 75% of its service life (10 to 20 years, depending on base rock and asphalt thickness), deterioration accelerates. If routine maintenance is not performed, restoration costs may be four to five times higher. An overlay can give you a new surface for a fraction of the cost of starting over.
What can be expected?
Traffic on roadways is commonly allowed access soon after paving. During a road overlay project, residents must remove all vehicles from the street. The street is first sprayed with a thin layer of asphalt called a tack coat so that the new pavement will stick to the old pavement. The overlay is then applied. Traffic should be kept off the new pavement for at least four hours after it is laid.