Asphalt Emulsions And Their Role In Chip Seal Application As A Pavement Maintenance Technique

What is a chip seal?

A chip seal or single surface treatment is the single most important low cost maintenance method used today. Chip seals produce an all-weather surface that renews weathered pavements, improves skid resistance, aides in lane demarcation, and seals and protects the underlying road surface.

How is a chip seal applied?

First, repair potholes and seal large cracks in the old road surface. Allow enough curing time for these treatments before applying the chip seal. Prior to chip seal application clean the road surface using a power sweeper or rotary broom. An asphalt emulsion is then uniformly spray-applied by an asphalt emulsion distributor and then chips are applied evenly by using a self-propelled or a truck-attached mechanical spreader. A Pneumatic-tired roller is then used to embed the aggregate into the asphalt film. Finally, loose particles are removed after the chip seal treatment has cured completely.

What types of asphalt emulsions are used for chip seals?

Typical asphalt emulsions used in chip seals are CRS-2, RS-2, or HFRS-2. Additionally, for higher volume traffic roadways polymer modified versions of these asphalt emulsions can be used.

Is there any advantage in using an asphalt emulsion over hot asphalt in the chip seal application process?

Asphalt emulsions are applied at much lower temperatures. Thus, there is energy savings and improved safety when applying a chip seal using asphalt emulsions.

What are some keys to a successful chip seal surface treatment?

  • Coordinate construction to ensure continuous operation.
  • Use hard, cubical, and clean aggregate.
  • Properly calibrate application equipment.
  • Maintain traffic control while chip seal application cures.

Where can I learn more about chip seals and other maintenance applications that use asphalt emulsions?

You can order AEMA’s Basic Asphalt Emulsion CD-Rom right here on this web site – just click here.

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Asphalt Emulsion Manufacturers Association
800 Roosevelt Road, Building C-312
Glen Ellyn, IL 60137
630.942.6579

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