Asphalt is composed of the following:

a) mineral aggregate – stone, sand
b) asphalt binder – petroleum derivative

Asphalt pavement is a mixture of stone, sand, and asphaltic binder, with the bituminous material comprising between 4% and 0% of the total. Most asphalts are mixed, heated, and blended in a batch plant. The asphalt is then hauled and spread to a uniform depth and rolled until compacted.

  • 6-10 Inches Compacted Base
  • 3-4 Inches Rock or Crush n Run
  • 2 Inches Binder
  • 3 Inches Topping or Finish Coat (Typical Application Conditions Vary)


Failures in the construction of an asphalt pavement may be attributed to:

  • insufficient or improperly compacted base
  • poor drainage
  • over-compaction or under-compaction of asphalt
  • asphalt is not at optimum temperature when applied

A good asphalt pavement seldom wears out, it is destroyed by external factors.

  • water penetrates asphalt and destroys base
  • sunlight (oxidation)breaks down the liquid asphalt that holds the aggregate together – causes raveling and shrinking cracks invites water
  • petroleum spills – gas and oil spots soften the asphalt



  • alligatored (areas of connecting cracks)
  • edge
  • slippage (typical of improper compaction)
  • reflection (older cracks occurring in new overlay) – edge joint
  • shrinkage
  • widening


  • channels or ruts
  • corrugations and shoving – grade depressions
  • upheaval
  • utility cut depressions


  • potholes
  • raveling
  • gas and oil spillage

The process of deterioration begins as soon as the asphalt is put down. In normal conditions, after 3 to 5 years major deterioration is taking place.

  • oxidation (sunlight) is causing asphalt to turn gray and brittle, resulting in cracking.
  • water is entering cracks, freezing during the freeze/thaw cycle, and causing larger cracks and potholes.
  • rain is entering cracks and causing base damage.