The progressive disintegration of an HMA layer from the surface downward as a result of the dislodgement of aggregate particles.

Raveling possibly resulting from segregation, temperature differentials or inadequate compaction.

Raveling that is likely the result of segregation and/or construction-related temperature differentials.


Loose debris on the pavement, roughness, water collecting in the raveled locations resulting in vehicle hydroplaning, loss of skid resistance

Possible Causes

  • Loss of bond between aggregate particles and the asphalt binder as a result of:
    • A dust coating on the aggregate particles that forces the asphalt binder to bond with the dust rather than the aggregate
    • Aggregate segregation.  If fine particles are missing from the aggregate matrix, then the asphalt binder is only able to bind the remaining coarse particles at their relatively few contact points.
    • Inadequate compaction during construction.  High density is required to develop sufficient cohesion within the HMA.
  • Mechanical dislodging by certain types of traffic (studded tires, snowplow blades or tracked vehicles).


A raveled pavement should be investigated to determine the root cause of failure.  Repair strategies generally fall into one of two categories:

  • Small, localized areas of raveling.  Remove the raveled pavement and patch.
  • Large raveled areas indicative of general HMA failure.  Remove the damaged pavement and overlay.