Breakdown: Dodging potholes lately? Here’s why they form
MEMPHIS, Tenn. (WMC) - Roads are made with several layers. The top layer is waterproof and curved to allow water to drain off the road and into the shoulder.
The surface of roads can develop cracks due to traffic, heating and cooling of the road surface. At night, the water can freeze and expand. Here comes the sun, the next day and it will cause the underlying ice to melt. The sun does help to dry up the water that seeps into the ground and the dark-colored roadbed helps absorb the sun’s rays and dry out the water.
However, the melted ice can move to a different part of the layers of the road. The melted ice causes the pavement to contract and leave spaces on the surface under the pavement. The spaces are areas where water can get trapped.
Traffic can make those gaps worse and the cracks can widen which allows more water to flow in and get trapped. The water that gets in can freeze and the freeze-thaw cycle will weaken the surface of the road. The collection of water underneath can soften the road base.
The weight of cars, trucks, and tractor-trailers can allow roads to collapse. Where this collapse forms, a pothole is then formed, and continued traffic on potholes can make the pothole bigger.
Potholes can develop year-round but are most common in the early spring. Spring is prime pothole season because at night temperatures fall below freezing and daytime temperatures above freezing because of the longer daylight hours.
According to experts, repairing potholes can be a challenge because the potholes are not just filled but also sealed to keep water from seeping into any cracks.
Here in the Mid-South the ever-changing weather and the big swings in temperature mean more and more potholes across the region.
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