Progressive wearing away of the surface as aggregate particles, first fines and then coarser stone, break loose. It starts where the binder has aged and hardened, where density is low, or where segregation left coarse open spots, and water, snowplows and traffic speed it up. Raveled surfaces look rough and pitted with loose stone along the edges, and they invite potholes.
Raveling in all the truck-end spots, every 150 feet like clockwork, that's segregation, not bad oil.
Also heard as
- ravelling
Do not mix it up with
- Stripping: Stripping is the binder losing its grip on stone from moisture, often deep inside the layer; raveling is surface loss from several causes.
Related terms
Segregation
Separation of coarse and fine aggregate, or of hot and cold mix, that leaves open, low-density spots in the mat.
Stripping
Loss of the binder's bond to the aggregate surface, caused by moisture working into the mix.
Dry
Describes mix short on binder: dull brown, harsh to rake and likely to ravel early.
Pothole
A bowl-shaped hole through the pavement surface where pieces of asphalt have broken out.