The City of Portland’s contractor, J. Carroll Weaver, Inc., plans to begin the Phase 11 Streets Improvement Project on several roadways throughout the City soon. The upcoming streets improvement project is necessary to help maintain our streets and extend their life expectancy. This project involves two repair methods: (1) the preventative maintenance seal coat & (2) milling and overlay
Which streets are included in the is phase?
Every street in the City was scanned with a ground penetrating radar by the City’s consulting engineer. The City’s consulting engineer analyzed the scan and developed a Pavement Condition Index (PCI). After reviewing the PCI, the City’s engineer created a 6-year sequencing plan to maintain and increase the PCI scores of all City streets.
Crews plan to work on several streets on the east side of U.S. 181. (Please see the Project Map below). Clustering the work reduces traffic disruptions and reduces the cost of the project. The next phase of the Streets Improvement Program will focus on the west side of U.S. 181 next year.
How does the City determine which streets receive seal coats and which receive overlays?
Newer streets with higher PCI scores are good candidates for seal coats. The seal coat process is a preventative maintenance option that uses oil to seal the cracks in the roadway and prevent water from leaking into the asphalt causing deterioration. Seal coats are extremely effective, as well as inexpensive, in creating better efficiency for our tax dollars.
Milling and overlaying is required for roadways with a lower PCI score caused by damages to the base and subgrade of the roadway. On these streets, the contractor will mill the existing asphalt, make base and subgrade repairs, and then overlay the repairs with new asphalt.
Why does the City seal coat streets that are in good condition?
Street seal coating is a preventative maintenance activity for streets that are in "good" condition so they will remain in good condition and not deteriorate to a lesser quality that would require a more expensive maintenance activity at a later date. A typical seal coating maintenance cycle for an asphalt-paved street is between 8 to 10 years due to asphalt "oxidation" (similar to the way metal will rust and break down).
Why are seal coats important?
The City of Portland has been using seal coats for several decades to keep streets in good condition and prolong their lifetime. The street aging process is slow at first, but after nine to ten years, the process accelerates. Cracks widen and allow more water to enter, creating potholes and requiring patches. A seal coat is applied to streets to stop the oxidation and slow the cracking. This treatment can substantially extend the life of a street as much as 15 years.
Seal Coat Process - What to Expect
The construction crew will provide instructions to homeowners on when to move vehicles, turn off sprinkler systems, etc. via a door-hanger card one week ahead of time and 24 hours prior to the crews conducting the maintenance on your street. Temporary road closures may be necessary. Crews will place temporary barricades and signal detours when necessary.
Crews plan to prepare the areas for the street work by cleaning the roadways and removing other vegetation from the construction area. Once the street is cleaned, crews will assess the area and apply a test strip to the roadway to determine the best application rates for a particular street. On most streets, the first pass of work is done very quickly, taking about 30 minutes per block and lane. (Note that some driveways may be closed off during this time - the crews will work with homeowners to minimize disruptions as much as possible.) The first sweeping, however, will not take place for 24 to 36 hours from this time. It takes about a month after seal coat maintenance for the new surface to completely cure and lock firmly into place. During this time, the road is open to regular traffic.