This is called ‘Edge Cracking’ and you will see formation of crescent-shaped cracks near the edge of a road like we see in this picture. It is caused by lack of support of the road edge, sometimes due to poorly drained or weak shoulders. If left untreated, additional cracks will form. This happened on Jalan Lembah Permai in Penang and it happened right after heavy rain.
Poor drainage could also be the cause of edge cracking, as it weakens the base, which hastens the deterioration of the pavement. Water ponding (a buildup of water which can also be called puddling) happens more frequently near the edge than in the center of the road path, as roads are usually sloped to prevent in-lane ponding. This leads to excess moisture in the shoulders and subbase at the road edge.
Possible causes of roads cracking at the edge,
- Lack of lateral support
- Settlement of underlying material
- Shrinkage of drying out soil
- Weak base or subgrade layer
- Poor drainage
- Heavy traffic or vegetation along edge
