Potholes

Potholes

Small, bowl-shaped depressions in the pavement surface that penetrate all the way through the HMA layer down to the base course.  They generally have sharp edges and vertical sides near the top of the hole.  Potholes are most likely to occur on roads with thin HMA surfaces (1 to 2 inches) and seldom occur on roads with 4 inch or deeper HMA surfaces (Roberts et al., 1996).

Polished Aggregate

Polished Aggregate

Two adjacent SMA pavements at the NCAT Test Track near Auburn, AL.  The pavement on the right uses river rock, which is more susceptible to abrasion, as its aggregate and is showing some signs of aggregate polishing. 

Patching

Patching

An area of pavement that has been replaced with new material to repair the existing pavement.  A patch is considered a defect no matter how well it performs.

Longitudinal Cracking

Longitudinal Cracking

Cracks parallel to the pavement’s centerline or laydown direction.  Usually a type of fatigue cracking.

Joint Reflection Cracking

Joint Reflection Cracking

Cracks in a flexible overlay of a rigid pavement.  The cracks occur directly over the underlying rigid pavement joints.  Joint reflection cracking does not include reflection cracks that occur away from an underlying joint or from any other type of base (e.g., cement or lime stabilized).

Depression

Depression

Localized pavement surface areas with slightly lower elevations than the surrounding pavement.  Depressions are very noticeable after a rain when they fill with water.

Corrugation and Shoving

Corrugation and Shoving

 A form of plastic movement typified by ripples (corrugation) or an abrupt wave (shoving) across the pavement surface. The distortion is perpendicular to the traffic direction. Usually occurs at points where traffic starts and stops (corrugation) or areas where HMA abuts a rigid object (shoving).