2011 Street Maintenance

Street Maintenance (PAVER) Program
The City utilizes three preventative maintenance procedures each year. This consists of a crack seal, a chip seal and an overlay. Each of these processes help to mitigate the deterioration of our City streets.
As asphalt pavement progresses through its performance life cycle, its appearance diminishes over time. Fine hairline cracks spread and deepen within the asphalt. Without ongoing maintenance, water may enter through cracks and holes may form, undermining the substrate. In this case, the most effective form of repair is to remove and replace the deteriorated area.

As soon as freshly laid hot asphalt pavement mix begins to cool, the aging process begins.
When oxygen in the air and water combine with asphaltic binder of the pavement, a chemical change takes place. At first, this process is necessary for the pavement to become hard and firm. Later, if this process is not arrested, a complete deterioration of the asphaltic binder will take place and reduce the pavement to a layer of loose stone.

Enemies of our City streets include: gas, oil, sun oxidation, salt, water penetration, and hot or cold weather.

2011 Crack Seal

This project will crack seal various streets throughout the City amounting to 18.75 miles of street or 3.6 million square feet.

Here is a map of the 2011 Crack Seal areas
Crack sealing is used as a first defense against pavement deterioration because it offers several important benefits. Effective crack sealing keeps water from entering and weakening the base or sub-base. It helps preserve the pavement adjacent to the cracks; prevents sand, stone, and dirt from making its way into open cracks causing compressive stresses; and extends pavement life by minimizing crack growth.

Proper attention to cracks will prevent problems from spreading and extend the life of the pavement. Pavement repair in the early stages of deterioration will pay big dividends later by delaying costly resurfacing.

2011 Overlay
Streets to be overlayed this summer are 24th Street West (from Central Avenue to Grand Avenue), Grand Avenue (from 100 feet East of 24th Street West to the BBWA Canal) and 1st Avenue North from North 18th Street to North 28th Street.

Here is a map of the 2011 Overlay areas
The overlay process replaces existing deteriorated asphalt surfaces with new asphalt. Generally, the top two inches are milled off as a first step. Once this layer has been removed any exposed problem areas are removed and replaced in a dig-out process. The surface is then prepared and a new two inches of asphalt is put in place.

2011 Chip Seal
Streets to be chip sealed are shown on the linked map below.

Here is a map of the 2011 Chip Seal areas

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 asphalt concrete 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?
  1. Chip seals provide the opportunity to maintain the roads for very low cost.
  2. A chip seal is about one tenth the cost of a conventional asphalt overlay.
  3. By extending the time between asphalt overlays, chip seals result in lower costs over the long term.
  4. By placing a chip seal sooner than an asphalt overlay would be placed, the traveling public benefits from roads maintained in better condition.
  5. Chip seals enhance safety by providing good skid resistance.
  6. Chip seals provide an effective moisture barrier for the underlying pavement against water intrusion by sealing cracks in the pavement.
  7. 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 starts by spraying each lane with hot liquid asphalt to assure an even application. The asphalt used 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.