Pavement failure is caused by a number of variables including weak subgrade, water intrusion, and stress from heavy vehicles. The surface cracking by far makes up for the majority of pavement failure issues because of its tendency to spread and the wide variety of elements that can cause cracking.
Roads that are built on poor subgrade (foundation) might lead to damaged roads. Some of the typical pavement failures :
Rutting is channeled depressions in an asphalt surface that form over time from exceeded weight limits and improper base construction. Over time heavy vehicles will begin to compact the asphalt along a roadway creating tire ruts
Alligator cracking forms when the subgrade and asphalt base begins to compress from bearing heavy vehicles. Alligator cracking is commonly found at intersection where vehicles are stopped for a continuous amount of time. Initial cracks will form and spread through water intrusion and further asphalt base compression.
Potholes are form through prolonged water intrusion from existing cracks in the surface. If alligator cracks and other asphalt stress cracks are not treated, water will begin to erode the surface all the way down to the subgrade. This will cause large holes to form in the asphalt which will spread and cause damage to vehicles.