2021 Cape and Slurry Seal

Project Update 7/9/2021

Most of the concrete flatwork is in place for the Niles Blvd and Rancho Arroyo Safe and Complete Street Project. The slurry seal on Niles Blvd. from Nursery Avenue to the Niles Bridge is scheduled for next Monday, July 12th through Tuesday, July 13th.  The traffic signal at Rock and flashing beacons at Rancho Arroyo and El Portal are expected to be installed in September.

The Project

The Cape and Slurry Seal Project is an effort on the part of the City’s Engineering and Maintenance Divisions to perform preventive maintenance on existing street pavements. The surface treatments; which include cape seals and slurry seals are all designed to extend the pavement life of each street. The work is less intensive than a reconstruction project, but more economical, which allows for a greater number of streets to be treated.

This year's project includes 134 street segments, consisting of approximate 26 centerline miles of roadway and covering 5.5 million square feet of pavement surface. The work is scheduled for summer of 2021.

Project Map

2021 Cape and Slurry-Project Map Opens in new window

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List of Streets


Alameda County Transportation Commission Your Voter Approved Tax Dollars at WorkSB1-Logo

Funding for the project includes revenue from State of California Senate Bill 1 (SB1), the Road Repair and Accountability Act of 2017.

The funding for this project also includes voter-approved funding from Measure B. The Alameda County Transportation Commission allocates this funding to local agencies for use of various transportation improvement projects including this one.

Anticipated Impacts on the Public

Temporary lane closures will occur when cape and slurry seal work is in process. Traffic flow may even be affected on streets adjacent to where the work is occurring.

Parking will be restricted on streets when cape or slurry seal work occurs. No parking signs will be posted in advance of the parking restrictions and advance notices will be delivered to nearby properties.

Work will occur in a series of activities. The sequence of activities may vary, but the following can be expected:

  1. weed spraying
  2. weed removal
  3. crack sealing
  4. base repairs/skin patches
  5. chip seal (cape streets only)
  6. slurry seal (all streets)
  7. restriping of traffic lanes
  8. curb ramp installations

Construction Process

Base Repairs and Skin Patches – Base repairs are localized repairs in the pavement where a portion of the pavement is ground out and replaced with new asphalt. Base repairs are usually performed in relatively small areas of pavement where pavement base is no longer supporting the pavement surface properly. A skin patch is used to level out portions of pavements where surface depressions exist.

Crack Sealing – Crack sealing involves placing elastic material directly into cracks in pavement. Water intrusion into pavement cracks causes pavement deterioration. Sealing the cracks prevents water intrusion from occurring and extends the useful life of the pavement. Prior to crack sealing, all cracks will be sprayed with herbicide to remove weed growth. Streets receiving a slurry seal will be crack sealed.

Slurry Seal – Slurry seals involve spraying a mixture of polymer modified asphalt emulsion, well-graded fine aggregate, mineral filler, and water on the pavement surface. It is used to fill cracks and seal areas of old pavements, to restore a uniform surface texture, to seal the surface to prevent moisture and air intrusion into the pavement, and to improve skid resistance. Streets that are in relatively good condition will be slurry sealed in order to preserve its condition.

Cape Seal – A cape seal is a thin surface treatment constructed using a two-step process. The first step involves placing a “chip seal,” which places small graded stone (chips) on a liquid asphalt blend that is sprayed on the pavement surface. The chip seal is rolled to embed the chips securely to the surface. The second step involves a slurry seal, which is applied on top of the newly applied chip seal (normally one or two weeks after). Streets that are in fair condition or worse will be cape sealed.

Curb Ramps – Part of the effort to maintain the pavement will involve improving the street intersections with new curb ramps. The intersections will receive new curb ramps if a sidewalk has no existing curb ramps in place or if the existing curb ramps were built under an older standard. Curb ramps will be installed after the placement of slurry seal.


Engineering Division