How are potholes formed?


By the time we see them they are fully developed but how did they get to that point and what causes them in the first place.

In: Engineering

It’s caused by two things. The first and biggest factor is water freezing in any grooves or openings from imperfections in the pavement which causes expansion and separation. The second is all the cars rolling over these chipped off pieces.

A crack in the road surface lets water through. That may wash a little material away and get underneath where it tends to lubricate the stones forming the base so they move when the weight of a vehicle goes over.

Worse is if it freezes during the winter months. Ice takes up more room than the water it came from and the expansion forces cracks open. When it thaws, the unsupported edges crumble, letting more water in and the cycle continues on the next freeze.

Once you get a large enough pothole, wheels jolting into it excavate more and more material.

Water gets into cracks in roads and expands when it freezes, loosening asphalt. When it happens enough, pieces break loose. Since ice is often associated with snow, plows scraping large metal plow blades along the road makes the loose pavement worse, further loosening loose sections, even popping chunks out