What is a chip seal?
Chip seal is applied by spraying a heavy coating of emulsified asphalt oil onto a road surface and then covering the oil with rock. Rollers are then utilized to embed the rock into the oil forming a new wear surface when complete.
What is a fog seal?
A fog seal is a light application to an existing surface of a slow-setting asphalt emulsion diluted with water. Typically used to renew old asphalt surfaces that have become dry and brittle with age, it is also utilized to coat newly chip sealed surfaces. Coating the new chip seal surface eliminates dust, aids in retention of the newly applied rock, and helps to reduce tire noise on the coarse surface. At a cost of approximately $ .10 per square yard, a fog seal can add years to the life of a chip seal before additional treatment is required.
How is chip seal with fog seal applied?
Why a chip seal?
A chip seal is applied when the pavement deterioration is greater than what a slurry seal is designed to correct, yet has not deteriorated to the point of requiring an expensive asphalt overlay. A chip seal prevents water penetration reducing subsequent damage to the road bed, along with providing a new-wearing surface. Used with crack sealing and surface patching, a chip seal significantly extends the life of a neighborhood street.
How are streets identified for chip seal?
Using our Pavement Management System, selected streets are identified by their condition. Typically, these are streets where a slurry seal alone would prove to be ineffective. Each street is then researched for other pending utility projects (water, sewer lines, etc.). Finally, each potential street is field-verified for condition and community value and selected for our list as budgeted funds allow.
What will City crews be doing to prepare the streets for a chip seal?
City Streets Section crews will be sealing cracks and patching most defects prior to the actual chip seal application. These activities may require more than one visit to your street due to the specialized nature of each repair method.
How is the project funded?
Funding for the Chip Seal Program is provided through revenues collected from gas taxes.
How will this affect access to our street?
During the chip seal application, only local traffic access will be allowed on some streets, while others will have traffic controlled by flaggers and a pilot car. In both situations, you can expect short duration interruptions to traffic flow. You will be able to drive on the chip seal fairly soon, though we advise reduced speeds for a few days to minimize flying rock. We will notify you at least 72 hours in advance prior to commencing work on your street.
What about the loose gravel on the streets?
A certain amount of aggregate applied in the chip seal process will work loose as the chip seal cures. We will post advisory signs and ask that vehicle speeds be kept down (15 to 20 mph) to prevent flying rock from damaging other vehicles until the loose rock has been removed.
What else can we expect?
Chip seals leave behind a coarse, abrasive surface that can cause increased tire noise and a rough ride for bicycles, skateboards, roller blades, etc. There can also be dust present from traffic for a few days after the application. The fog seal will significantly reduce tire noise, eliminate any dust, and bind the remaining rock into a smooth and hard-wearing surface.
If you have any questions or need additional information, please call the Neighborhood Streets Rehabilitation Program information line at 503-589-2166.