Longitudinal Cracking


Cracks parallel to the pavement’s centerline or laydown direction. Can be a type of fatigue cracking or top-down cracking.

Figure 1: Longitudinal cracking appearing as the onset of fatigue cracking.

Figure 2: Longitudinal cracking from poor longitudinal joint construction.

Figure 3: Longitudinal cracking from poor longitudinal joint construction.


Allows moisture infiltration, roughness, and it may indicate the possible onset of alligator cracking and structural failure.

Possible Causes

Poor joint construction or location. Joints are generally the least dense areas of a pavement. Therefore, they should be constructed outside of the wheelpath so that they are only infrequently loaded. Joints in the wheelpath like those shown in third through fifth figures above, will general fail prematurely.
A reflective crack from an underlying layer (not including joint reflection cracking)
HMA fatigue (indicates the onset of future alligator cracking)
top-down cracking


Strategies depend upon the severity and extent of the cracking:

  • Low severity cracks (< 1/2 inch wide and infrequent cracks). Crack seal to prevent (1) entry of moisture into the subgrade through the cracks and (2) further raveling of the crack edges. HMA can provide years of satisfactory service after developing small cracks if they are kept sealed (Roberts et. al., 1996[1]).
  • High severity cracks (> 1/2 inch wide and numerous cracks). Remove and replace the cracked pavement layer with an overlay.

Footnotes    (↵ returns to text)
  1. Hot Mix Asphalt Materials, Mixture Design, and Construction.  National Asphalt Paving Association Education Foundation.  Lanham, MD.




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