03/04/2023
According to the US Army Corps of Engineers's Cold Regions Research and Engineering Laboratory, pothole formation requires two factors to be present at the same time: water and traffic. Water weakens the soil beneath the pavement while traffic applies the loads that stress the pavement past the breaking point. Potholes form progressively from fatigue of the road surface which can lead to a precursor failure pattern known as crocodile (or alligator) cracking.
Eventually, chunks of pavement between the fatigue cracks gradually work loose, and may then be plucked or forced out of the surface by continued wheel loads to create a pothole.
In areas subject to freezing and thawing, frost heaving can damage a pavement and create openings for water to enter. In the spring, thaw of pavements accelerates this process when the thawing of upper portions of the soil structure in a pavement cannot drain past still-frozen lower layers, thus saturating the supporting soil and weakening it.
Potholes can grow to several feet in width, though they usually only develop to depths of a few inches. If they become large enough, damage to tires, wheels, and vehicle suspensions is liable to occur. Serious road accidents can occur as a direct result, especially on those roads where vehicle speeds are greater.
Potholes may result from four main causes:
1. Insufficient pavement thickness to support traffic during freeze/thaw periods without localized failures
2. Insufficient drainage
3. Failures at utility trenches and castings (manhole and drain casings)
4. Pavement defects and cracks left unmaintained and unsealed so as to admit moisture and compromise the structural integrity of the pavement
