Chip Seal Facts

“Chip Sealing” is a common pavement maintenance practice that extends pavement life and provides a good driving surface. Mohave County maintains 836 centerline miles of roadway and strives to chip seal 80 – 100 miles annually. Chip seals typically last seven to ten years, which will vary with the amount of daily traffic and heavy truck traffic. Public Works inspects and analyses paved road conditions annually from which candidate roads are added to the chip seal program. This fact sheet is prepared to provide Mohave County residents information about the chip seal program by answering some of the frequently asked questions.

Why Use Chip Seals?

• Chip seals weatherproof existing paved roads toward preventing surface (storm) water from infiltrating into the pavement structure through cracks and accelerating its deterioration and ultimate failure. 
• Chip seals cost less than 1/5th that of a 2-inch asphalt overlay. 
• 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.

What Steps Are Involved in Chip Seals?

An asphalt distributor truck starts by spraying one lane with hot liquid asphalt emulsion to adhere the new layer of chip seal with the existing road. Public Works commonly uses CRS-2P emulsion containing a latex polymer, which remains flexible and absorbs stresses without permanent deformation. Application temperatures for emulsions are typically between 140°F and 160°F since they are one-third water. A chip spreader follows as rapidly as possible with a rock application, preferably within one minute. The asphalt emulsion must remain fluid enough to allow the rocks to be embedded by the displacement of the asphalt. The rocks are an aggregate crushed to a special specification for size and cleanliness. Next, pneumatic rollers set the rock into the liquid asphalt. Rolling orients the flat sides of the rock down and produces a tighter chip seal. The Traffic Control Division of Public Works reapplies permanent road striping before the end of the season using an industry best striping machine and methods.

What Issues Affect a Quality Chip Seal Application?

Since a roadway is rarely closed to traffic for the chip seal application, a smooth flow of traffic through the work area is required. Driving slowly, not turning sharply, or braking quickly or spinning tires is crucial for the fresh chip seal to properly set and cure. Until the Road Division sweeps a newly chip sealed road after its cure period, motorists must adhere to posted, temporary/construction 25 mph speed limit so chip rock does not become dislodged and threaten damage to passing or following vehicles by “flying” chip rock. Please be patient. Traveling at the posted construction speed limit in construction zones will ensure your safety and the safety of others including the County road crews.

What Does It Cost?

A mile of chip seal costs Mohave County about $23,000 in oil and aggregate materials, proving a very a cost effective total surface maintenance treatment alternative to preserving Mohave County paved road assets.

Who Does the Work?

The Road Division of Public Works executes the chip seal program through its talented heavy maintenance crews, and the Engineering Division of Public Works provides experienced construction inspectors to review and document work performed.

When Is the Work Done?

The chip seal program usually occurs from March through May and occasionally in the fall prior to ambient (temperature) conditions preventing quality application