What is a chip seal?

Chip seals are the most widely used pavement preservation method. They produce an all-weather surface that renews weathered pavements, improves skid resistance, aids in lane demarcation and seals and protects the underlying road surface. While the single surface treatment is the most commonly referenced, there are many types of chip seals including singles, doubles, triples, sandwich, inverted, racked in, etc. Each has a different construction technique and is chosen for a particular purpose.

How is a chip seal applied?

Potholes are sealed, and any large cracks in the road surface are repaired. Sufficient curing of these repairs is allowed before applying the chip seal. The road surface is then cleaned using a power sweeper or rotary broom. For a conventional treatment like a single course chip seal, an asphalt emulsion is then uniformly spray-applied by an asphalt emulsion distributor, and aggregate (chips) are evenly appliedwith a self-propelled or a truck-attached mechanical spreader. A pneumatic tired roller is then used to embed the aggregate into the asphalt film. After initial cure, excess aggregate is removed by brooming. After the chip seal treatment has cured completely, the surface may be swept again and striping applied.

What types of asphalt emulsions are used for chip seals?

Typical asphalt emulsions used in chip seals are CRS-2, RS-2, and HFRS-2. For higher volume traffic roadways, polymer modified versions of these asphalt emulsions, like CRS-2P and CHFRS-2P, are used. See your state’s Product Locations & Applications page for more options.

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