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Public Works Street Services Redwood City, California
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Repair and Maintenance Treatments

City crews prepare the streets for the maintenance treatments by performing:

  • Road and Maintenance TreatmentsCracksealing – Filling of cracks in the asphalt with hot liquid material that dries and reduces water seepage under the roadway.
  • Area or spot asphalt repairs - Using a backhoe or grinder to excavate failed sections of roadway and then replacing new base material and asphalt.
  • Leveling asphalt layers – Paving thin (non-structural) asphalt overlays to smooth the roadway surface prior to a chip seal treatment (see ‘chip seal’ below).

High quality streets are maintained by using one or more of five different treatments. Which treatment is applied is determined by the pavement’s condition and the volume and size of vehicles regularly traveling on the street. The goal is to provide safe, efficient thoroughfares, while minimizing long-term maintenance costs. The following treatments are ranked in order of most to least substantial and expensive repairs.

  1. Reconstruction – The complete removal of curbs, roadway, and base followed by the new construction of the street and curb. Usually, the sidewalks and utilities under the roadway surface are included in this project. The street is under construction for weeks to months. This treatment is the most disruptive to the neighborhood. The life expectancy is at least fifteen years. This is the most expensive treatment usually reserved for the busiest bus and truck routes and streets in very poor condition.
  2. Overlay – The edge of the roadway is usually ground down to the depth of the new paving layer to keep the original flow line or gutter line intact. The street surface is oiled to help the new asphalt adhere to the existing layer. A paving machine is used to lay asphalt in lane-width or wider passes to apply a level and smooth structural layer of asphalt (usually at least two inches thick). The street is under construction for usually two different days – one day to grind and one day to pave. The life expectancy is between ten and fifteen years depending on use and traffic. This is the next most expensive treatment and used on the busiest streets where significant bus and truck traffic are present.
  3. Chip Seal – The surface of the street is coated with a thin hot temperature emulsion layer containing melted rubber. Small rock chips are spread over the emulsion and rolled into place. The excess rock chips are swept clean. Normally, the City covers the chip seal with a slurry seal to provide a finished look to the street and hold the chips in place. The street is usually under construction for three different days – one day to prepare the street, one day to chip seal, and one day to slurry seal. The life expectancy is seven to twelve years. This is a mid-priced treatment that is typically used on neighborhood streets.
  4. Slurry Seal – The surface of the street is coated with a thin emulsion with liquid rubber and course sand layer that requires up to eight hours to cure. The street is usually under construction for two days, one day to prepare the street and one day to slurry seal. The life expectancy is five to seven years. This is a lower cost treatment used to keep good condition streets in good condition.
  5. Crack Seal – Cracks present in the street are cleaned using high-pressure air to blow out debris. Hot tar material is applied to fill the crack and smoothed using a squeegee to seal the crack. Sand is spread over the fill material to allow traffic to drive over the fill without sticking to it. This treatment extends the life of streets by eliminating moisture seeping under the asphalt into the base material. The street is usually under construction for part of a day. The life expectancy is from two to five years. This is the least expensive street maintenance activity.
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