Chip Seal
Bituminous pavement (also known as blacktop or asphalt) is considered a flexible pavement – meaning that movement underneath the road, as well as loads from vehicle traffic driving on the roadway, actually cause it to flex and move. Over time and prolonged exposure to the elements (sunlight, UV rays, rain, freeze/thaw), the pavement can become brittle. Seal coating (also referred to as chip sealing) is a process that applies a thin layer of asphalt emulsion and rock chips to the surface of the roadway to reseal it, with the goal of keeping the pavement flexible. The seal coat protects the pavement from the effects of the elements, fills in cracks and other defects, and increases skid resistance. Chip seals extend the life of bituminous pavement by 5 to 7 years.
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How It's Done
The process can be broken up into these main parts:
- Pre-cleaning: For the asphalt emulsion and chips to adhere properly, the road surface needs to be fairly clean. City crews will sweep and flush the roadway with water multiple times to make it as clean as possible.
- Seal Coat Application: a contractor will come in and spray the asphalt emulsion, spread chips and roll them into the roadway surface.
- Post-sweeping: once the emulsion has cured, excess rock chips will remain on the roadway. City crews will sweep up the excess chips, leaving a clean, coated road surface.
- Fog Sealing: On main roads and in cul-de-sac bulbs, an additional coating of oil is applied for durability. This is completed after all excess chips are removed.
- Pavement Markings: Once the seal coat work is complete and cleaned up, City crews will re-paint pavement markings on main roads (centerlines, crosswalks, turn arrows, etc.).