Chip Seal
Chip Sealing is done in many states in the U.S. It is a cost-effective way to maintain roads and saves significant tax dollars. Chip sealing is a yearly process on selected roads that puts a coating over the asphalt of a street to protect it from water and weather damage and to keep the roads in good condition.

During the 2016 Chip Seal season, ACHD will resurface 500 miles of roadway. The 2016 Chip Seal season will begin on Tuesday June 14, 2016 and last until late August, or early September.

View a video of Chip Sealing Chip Seal Process

Chip Seal Information:

2016 Chip Seal Areas

  • Zone 5

  • In preparation for the Chip Seal season, ACHD crews perform Crack Seal maintenance on streets within the Chip Seal zone. The sealant forms a long-lasting, resilient seal which is flexible and expandable in varying and extreme pavement temperatures. Crack Sealing prevents the invasion of surface water between the layers of asphalt and layers of roadway below it. Not all roads that receive a crack seal will receive a Chip Seal within the same year.

  • Hill Road Microseal

Why Do We Chip Seal?

Asphalt deteriorates in time because of the 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.

In 2009 the cost for chip Sealing was $23,000 a mile. Chip Sealing saves taxpayer dollars because it protects the road from deterioration and greatly delays the need for a new asphalt overlay to repair a deteriorated road. At this time, asphalt overlays (new blacktop) cost up to $265,000 per mile

Some preparation work will take place throughout the spring, and the Chip Seal process traditionally begins the first week in June. The work involved consists of four phases: applying the Chip Seal, sweeping excess chips, applying the fog coat, and microsealing cul-de-sacs. On-street parking will be affected during each phase.

We appreciate your patience during this time, and we realize that while the surface is not very compatible with skates or roller blades, it is still the most economical. For area boundary descriptions for our operations this year, please call 387.6325 at our urban division and 387.6350 for our rural division.

“I’d like to give credit to ACHD for chipsealing our subdivision, they did a beautiful job. They operate like a well oiled machine, and it was hot out there. My wife and I appreciate everything they did," said Ken Weland of Meridian.

Chip Sealing Operations

As a part of maintenance program, crews Chip Seal street surfaces (including new streets) to protect then from water and weather damage and to keep them in good condition.

A Chip Seal application to a road or street has many positive objectives:

  • Chip Seal to 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 Seal to change the texture of the road for skid resistance;
  • Chip Seal to supply minimal additional strength to the pavement;
  • Chip Seal to provide a moisture barrier;
  • Chip Seal to give better resistance to studded tires;
  • Chip Seal to correct existing pavement problems by sealing cracks.

What is a Chip Seal?

A Chip Seal is an application of asphalt followed with an aggregate "rock" cover. It is constructed to produce an initial placement or maintain an existing asphalt pavement.

How is it Done?

Prep Work

  • First, the road surface needs to be properly cleaned of debris and any holes patched.

Asphalt Application

  • Next, an asphalt distributor truck starts by shooting only one lane at a time with hot liquid asphalt to assure an even application. The asphalt used is applied at a temperature between 140 and 180 degrees Farenheit. After cooling, this asphalt remains slightly flexible to maintain its hold on the rocks.

Rock Application

  • Another piece of equipment, the 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 fresh oil. This is done to get the flat sides of the rock down and produce a tighter Chip Seal. It takes two to four passes of the roller to set the rock.

Second Lane

  • After the first lane has been shot, covered with rock and the rolling has begun, the equipment starts the second lane. The operation is the same as the first shot.


  • 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 as soon as possible after the asphalt has set up (three to seven days).

Fog Seal

  • ACHD follows each Chip Seal with a Fog Seal that helps set the rock and control fly-rock and dust. Fog Sealing also adds life to a Chip Seal. This is a separate process that follows sweeping by up to three weeks.


  • ACHD Seal Coats all old and new streets in a neighborhood to save money and prolong street surface life. On residential streets, six years will pass before the Seal Coating process is again necessary.