2013 Chip Seal Project (BST)
Timeline: June through August
Project Questions/Concerns - Contacts:
Greg Hardy 727-3689
Non-Functional Streets - see map)
Dan Jacobsen 727-3690
Functional Streets - see map)
Alex DeLaPena 727-3693
Media Contact: Evelyn Lusignan 585-4265
2013 Map of Streets to be Chip Sealed
Street Classes shown on map:
Non-Functional Class Streets
- Local collector and commercial streets for which the chip seal is financed using local funds.
Functional Class Streets -
Streets located on the Federal Aid system (typically arterial and collector streets). A recent STP grant will pay for approximately 85% of the cost for chip sealing these streets.
2013 Chip Seal Project Schedule - Coming Soon
What is “chip sealing”?
Chip sealing is a cost-effective way to maintain streets and saves significant tax dollars. Chip sealing puts a coating of asphalt oil and fine crushed rock over the existing pavement to protect the street surface from water and weather damage, and to keep the roads in good condition. As a part of the City’s maintenance program, we chip seal street surfaces (including newer streets) to protect them and to keep them in good condition.
Why do we chip seal?
Asphalt pavement deteriorates in time because of the vehicle loads, tire wear, sun and weather. A chip seal helps seal the surface and provides an armor coat for skid and weather resistance. The best aspect of chip sealing is simple economics.
What are the savings to taxpayers?
In 2012, the City will chip seal 14.32 miles of arterial streets at a total cost of $800,000 or $57,100 per mile. These costs included crack sealing and patching failing sections of the streets prior to the chip seal; plus sweeping, striping and engineering. A standard hot mix asphalt paving project for the same streets would have cost $7,141,400 or $498,700 per mile.
Where is Kennewick currently in preserving its streets?
It’s estimated that each year, over 25 miles of arterial or collector streets are due or past due for pavement treatment. The current cost to chip seal these streets and provide the optimum maintenance benefit is approximately $1.4 million per year. To preserve these same streets with hot mix asphalt would cost nearly $13 million per year. It should be noted that the above estimate does not include the commercial and residential classified streets that are also slipping behind in their maintenance schedule.
Kennewick has approximately 290 miles of streets. With a chip seal needing to be done every 7 years. To adequately preserve your City's streets, including residential streets, we need to chip seal nearly 41 miles of streets each year.
Why hasn’t Kennewick used chip seals in the past?
Prior to the early 2000’s the cost of hot mix asphalt and chip seals were nearly equal when comparing their life cycle costs. However, around 2003 asphalt prices more than doubled in cost while chip seal prices remained relatively unchanged. And while chip seal prices have slightly increased in the past five years, hot mix asphalt prices increased at a greater rate. As a result of the higher cost of hot mix asphalt, the City could no longer keep up with its hot mix asphalt overlay program and more streets were starting to reach or exceed their service life.
Some of the streets looked fine, why did you chip seal those?
This is an often heard refrain; however, streets may look okay, but actually be at the onset of distress. If you think about it, our streets are subject to hot, cold, dry, rain, snow, ice, and pounding by cars, trucks, buses, etc. As soon as streets are constructed they immediately begin to deteriorate. In the beginning this deterioration process is slow; however, this deterioration process accelerates near the end of the pavement service life. And like your car, if you don’t provide preventive maintenance or let the maintenance go too long, then you are looking at major costs for repairs or replacement. We cannot afford not to provide the preventative maintenance on our streets.
How are chip seals different from asphalt overlays?
The difference is in the construction method. Hot mix asphalt pavement is produced by heating liquid asphalt and mixing it with aggregate, with the mix then spread and compacted to form a durable road structure and riding surface. Chip sealing uses the same ingredients as hot mix asphalt paving, but the construction method is different. With chip seals, a thin film of heated asphalt liquid is sprayed on the road surface, followed by the placement of small aggregates (chips). The chips are then compacted to orient the chips for maximum adherence to the asphalt and excess stone is swept from the surface. The ingredients of hot mix asphalt and chip seals are the same; only the construction methods are different.
Why use chip seals?
- Chip seals maintain the existing pavement in its present condition by delaying further aging due to water and sun- this is equally important to new streets.
- Chip seals provide the City with the opportunity to maintain our streets for very low cost. A chip seal is about one-fourth to one-fifth the cost of a conventional asphalt overlay.
- A chip seal will supply minimal additional strength to the pavement.
- A chip seal will provide better resistance to studded tires.
- Chip seals provide an effective moisture barrier for the underlying pavement against water intrusion by sealing cracks in the pavement.
- Chip seals significantly reduce the need to crack seal. In hot weather, chip seals reseal cracks by flowing back together.
- Chip seals enhance safety by providing good skid resistance.
- Chip seals prevent deterioration of the asphalt surface from the effects of aging and oxidation due to water and sun.
How are chip seals placed?
First, the road surface needs to be properly cleaned of debris and any holes patched. Next, an asphalt distributor truck sprays each lane with hot liquid asphalt to assure an even application. The asphalt is applied at a temperature between 150 and 185 degrees Fahrenheit. A chip spreader follows as rapidly as possible with a rock application, preferably within one minute. The asphalt must be fluid so the rock will be embedded by the displacement of the asphalt. The rocks are an aggregate crushed to a special specification for size and cleanliness. Next, a rubber-tire roller is used to set the rock into the liquid asphalt. Rolling orients the flat sides of the rock down and produces a tighter chip seal. It takes two to four passes of the roller to set the rock. Sweeping is done at the completion of the chip seal process to remove surplus rock from the surface. This loose rock can grind and loosen rock set in the chip seal and damage the project. Sweeping is done within four hours of the rolling operation and typically, again a day or two later.