Once again, water is the primary culprit. Poor drainage patterns allowing water to pool on your pavement will result in structural failure, requiring full depth removal and replacement. These failed areas are most often identified by large blocks of alligator cracking, which if not corrected, will break loose creating potholes.
Other areas requiring full depth removal are isolated areas of sinking asphalt, or just the opposite, which are isolated areas of heaving asphalt.
The standard method of repair includes saw cutting just beyond the failed area, removing the failed asphalt and existing base material as required to a depth necessary to establish solid compaction. Furnish, deliver and install new aggregate base and new hot mix asphalt and compact to restore the integrity of the failed asphalt area.
Larger areas of asphalt decay will require more extensive methods of rehabilitation, ranging from surface milling and overlays to full depth pulverizing and repaving.
Areas to be surface skin patched are generally located near a source of water. In our desert, that normally means sprinklers. Constant surface water flowing over asphalt will erode and remove the surface aggregate, slowly carving and scarring the surface of your pavement. This surface decays, then distorts the drainage patterns, resulting in depressions, which if not corrected, will advance the structural failure requiring full depth removal and replacement.
Minor depressions, areas of distorted drainage, and areas of severe surface erosion can be corrected by applying a thin layer of hot mix asphalt to restore the integrity of the damaged asphalt. In medical terms, we are providing a skin graph on your asphalt pavement.