Hey Ray: Frost wedging
PITTSBURGH (KDKA) - You have probably noticed the commutes around the area are a lot rougher this time of year, as pot holes develop across the region. You likely heard it is due to the "freeze/thaw process", which is true, but that process drives what is called Frost Wedging.
Frost wedging is a process that sort of gives water the superpower of breaking up rocks, concrete, and even asphalt.
According to the National Snow and Ice Data Center, frost wedging is the mechanical disintegration, splitting or break-up of rock by the pressure of water freezing in cracks, crevices, pores, joints, or bedding planes.
The simple version of this is that water seeps into cracks and freezes. Since water expands when it is frozen, that expansion creates enough pressure to break hard substances. This isn't a quick process, though. It is usually a process that needs to be repeated several times to break hard surfaces open.
When water freezes, it expands the crack. This is where the thaw part of the freeze/thaw process comes in.
When the water melts, it seeps further into the rock. When that re-freezes, it expands the joint even more.
Locally, potholes are the most widespread issue we see, but Frost Wedging can lead to landslides, crack expansions on driveways, and it can break up rocks. Some of these issues can take years to show up, and others can occur in shorter periods of time.
There is not much you can do to stop it in nature since it is a natural process.
To prevent Frost Wedging from chipping apart your driveway, make sure to use the recommended ice melt during the winter and if you have any cracks in your driveway, you may want to fill those up with a proper crack filler.
