Street Pavement Maintenance Program
The City of Boulder uses a variety of pavement treatments to keep its transportation infrastructure of 305 center-line miles of roadway in good condition.
Crack Fill: cracks in the pavement are sealed to prevent moisture from entering the base and sub-base of a roadway, reducing pavement failures and potholes and extending the pavement life.
Chip Seal Program: Chip seal is a surface application used to prolong the life of an existing street by applying a liquid asphalt membrane binder (“seal”) and a layer of small crushed stone (“chip”) over the existing street surface. Chip seal typically extends the useful life of the existing pavement by eight to 12 years and is typically used on residential or lower-volume streets.
Streets that receive a chip seal typically require asphalt, curb and gutter repair in preparation for the actual chip seal application. The chip seal process does not significantly affect traffic but does require that parking be removed from the street while the work is being completed. The chip seal process typically takes two to three days. Typically, one to two days later, a thin layer of liquid asphalt “fog coat” is applied on top of the stone chips to provide further sealing of the pavement. The final step is sweeping the streets to remove any remaining chips that have come loose during the process.
Asphalt overlay – The roadway is resurfaced with two inches or more of hot mix asphalt.
Asphalt resurfacing or overlays are used on higher volume roads or lower volume streets that have deteriorated to a point that a chip seal or other pavement preservation treatments are no longer effective. The asphalt overlay provides approximately two inches of the new asphalt street surface to existing streets. An overlay typically requires some level of removing the existing surface by grinding, either along the edge or the full width of the street, depending on the condition of the street. The overlay process generally occurs in several phases. The first phase includes removal and replacement of deteriorated curbs and gutters, as well as reconstruction of selected sidewalk ramps to conform to Americans with Disabilities Act (ADA) criteria. The next phase includes milling of the roadway surface. The last phase includes the actual resurfacing of the road with new asphalt, combined with re-striping. The overlay process at times may include a phase to remove and patch some areas of the street that have extensive wear or damage beyond the surface of the pavement.
Asphalt reconstruction – The roadway is reconstructed by removing the existing asphalt, reconditioning the subgrade, and placing five inches of new asphalt pavement made from Hot Mix Asphalt.
At times, streets deteriorate to a point that requires total reconstruction of the pavement structure. Streets requiring reconstruction will typically require similar steps as an overlay, with pedestrian ramp and curb and gutter repair, but the entire pavement structure is removed, the subgrade is reconditioned and new asphalt and striping is completed.
Last Updated on Tuesday, 14 May 2013 16:58