The best way to protect the investment in your asphalt pavement is to be diligent about "preventative" maintenance such as crack filling and seal coating. But once asphalt decay has advanced past the stage where these are an appropriate remedy, it is necessary for a "reactionary" remedy. Asphalt patching is necessary for areas that are heavily cracked (or "alligatored"), sunken, exposed (potholes) or raised by roots or water damage.
The perimeter of the affected area will be sawcut to provide a clean, professional-looking edge and to provide maximum structural integrity. The old, decayed asphalt will be removed and disposed of. The subgrade will be inspected and appropriate action will be taken (such as clipping tree roots, bringing new crushed rock, or providing new compaction). New hot mix will then be placed and compacted. Tar seal is applied to the seams (of old adjacent to new) to prevent moisture penetration. As a general standard, asphalt thickness of 2-inches is appropriate. Areas that have high traffic volume or very heavy trucks may require a greater thickness.