Minnesota Department of Transportation

511 Travel Info

US 71 North

Kandiyohi County

Orange barrels on a highway

Chip seals

Chip sealing, also referred to as a seal coat, is a type of paving material that mixes asphalt with pieces of gravel. A thin layer of liquid asphalt is sprayed on first followed by the placement of gravel. The gravel is compacted and the excess stone is swept from the surface. Chip sealing protects the pavement, increases skid resistance and extends the life of the road.

What can you expect as a driver?

Driving: Although it seems natural to avoid a road that has been recently coated or fixed, chip sealing is unique in that it does not keep drivers from the road. You can drive on a freshly chip sealed road after it has been swept.

Appearance: A chip seal does look different than regular pavement. The chip seal lends a rough, rocky appearance to the road and is generally bulkier than asphalt. A chip seal may appear purple due to the type of stone used.

Sound: A road that has been chip sealed will not be as quiet as a new pavement. The rough surface can also cause an increase in vibration for bicyclists. After a winter of plowing, the vehicle noise will diminish and you will notice that the road will not sound as loud.

Purpose: Chip sealing serves many purposes:

  • Chip seals allow MnDOT the opportunity to preserve roads for a very low cost
  • Chips seals prevent deterioration of the pavement surface from the effects of aging and oxidation as a result of sun, water, traffic and plowing
  • Chip seals enhance safety by providing good skid resistance
  • In hot weather, chip seals re-seal cracks by flowing back together

Watch a chip seal application in action!