Block Cracking
Block cracks are interconnected cracks that divide the pavement into approximately rectangular pieces. The blocks may range in size from approximately 1 by 1 ft (0.3 by 0.3 m) to 10 by 10 ft (3 by 3 m). Block cracking is caused mainly by shrinkage of the asphalt concrete and daily temperature cycling, and it is not load associated. The occurrence of block cracking usually indicates that the asphalt has hardened significantly. Block cracking normally occurs over a large portion of pavement area.
Severity | Distress Example | Description |
---|---|---|
Low | ![]() | Blocks are defined by cracks that are nonspalled (sides of the crack are vertical) or lightly spalled, causing no foreign object damage (FOD) potential. Nonfilled cracks have 1/4 in (6 mm) or less mean width and filled cracks have filler in satisfactory condition. |
Medium | ![]() | Blocks are defined by either: filled or nonfilled cracks that are moderately spalled (some FOD potential), nonfilled cracks that are not spalled or have only minor spalling (some FOD potential), but have a mean width greater than approximately 1/4 in (6-mm); or filled cracks greater than 1/4 in (6 mm) that are not spalled or have only minor spalling (some FOD potential), but have filler in unsatisfactory condition. |
High | ![]() | Blocks are well defined by cracks that are severely spalled, causing a definite FOD potential. |