The caller wondered what happens to all that asphalt that comes out of all those pot holes and you bums gave her a bum steer! Here’s the real answer…
Hey Guys, Love the show and listen as often as I can. Re: Your explanation of pot holes. Well, what you said was partially accurate, though the hole actually is caused by impact. As you said, when the top surface opens up the process begins. Also correct, however, in order for the pot hole to get bigger you need water, as in a puddle. Explanation: When a car’s tire hits the puddle there is a tremendous amount of pressure generated, and the water, as vehicle for the impact, is forced against the surrounding asphault pushing those “bits”, as you said, out of the hole. The bigger the pot hole gets, more of the tire impacts the water, hence, more pressure and “bits” get shot out of the hole. Hope this is useful. Best, Don
SFS has the actual answer. driving through a pot hole can make it grow bigger, but seeping H2O freezing under the asphalt and expanding the ground then thawing is what makes a pothole… it’s like a mini sink hole.
Hey Guys, Love the show and listen as often as I can
You do know that the guys retired a couple of years ago and all you hear now are reruns.
The person who phoned in to ask that question is a person especially curious about things. We need more like her in America. Good on her for asking a question most of us never even thought about. My guess is that most of the broken up asphalt remains under the mud at the bottom of the pothole, and gets dug up and hauled away, or just gets paved over when they repair the pothole.
BTW, potholes don’t require freezing weather to form. We get lots of potholes here in coastal California too.
The Michigan pot holes post is so true, I live in Michigan right now and the pot holes are really numerous.
Potholes happen for a number of reasons and yes, you don’t need freezing weather. What’s common to most is water either freezing or moving water under the pavement to cause the
Loss of support. Some of the the best road beds use lots of rip rap under the roads to allow water to move through the road bed to the other side or drain below the frost line before they can do damage. But then, pot holes can be formed for other reasons too.
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