How are runways different form highways that they never seem to have potholes? Is it how they’re constructed? Or how they’re maintained?
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It’s salt!
They are not going to use salt on a runway because it is too corrosive to vital electronics, and the aluminum shell of the planes.
It’s no standing water!
Most potholes are created when freezing water expands while freezing.
It’s TLC!
If you only need to take care of a small amount of road It’s easy to keep it clean, sturdy, and clear of debris
Potholes form and grow when water seeps into small cracks in pavement, and the momentary spikes in water pressure from tires rolling over the crack force it to expand. On a busy highway, a crack can be driven over once every few seconds, whereas planes only roll down a runway once every few minutes, so the wear-and-tear on a runway is much less than on a road.
Runways are also inspected on a daily basis and repaired promptly, since even a small piece of debris flung up against a jet aircraft can lead to catastrophic failure in the right conditions.
Runways subsurface preparations are much deeper and stronger than even the interstate. There are millions of miles of roadways in the US, and maybe a few thousand miles of runways.
Even Germany’s vaunted Autobahn has an average subsurface preparation of about 28 inches (sand, pebbles, rocks, cement). The US interstate has an average of only 14 inches. Again, it comes down to cost savings.
https://upload.wikimedia.org/wikipedia/commons/c/c2/PavementStratum.JPG
I don’t have any specialized knowledge, but I saw some runway construction at an airport once and the concrete appeared to be several feet thick instead of the several inches thick concrete used in highways. It’s been quite a few years, but I remember the concrete being roughly as thick as a man is tall.
Hopefully a civil engineer will chime in and confirm or deny this.
It’s salt!
They are not going to use salt on a runway because it is too corrosive to vital electronics, and the aluminum shell of the planes.
It’s no standing water!
Most potholes are created when freezing water expands while freezing.
It’s TLC!
If you only need to take care of a small amount of road It’s easy to keep it clean, sturdy, and clear of debris
Potholes form and grow when water seeps into small cracks in pavement, and the momentary spikes in water pressure from tires rolling over the crack force it to expand. On a busy highway, a crack can be driven over once every few seconds, whereas planes only roll down a runway once every few minutes, so the wear-and-tear on a runway is much less than on a road.
Runways are also inspected on a daily basis and repaired promptly, since even a small piece of debris flung up against a jet aircraft can lead to catastrophic failure in the right conditions.
I don’t have any specialized knowledge, but I saw some runway construction at an airport once and the concrete appeared to be several feet thick instead of the several inches thick concrete used in highways. It’s been quite a few years, but I remember the concrete being roughly as thick as a man is tall.
Hopefully a civil engineer will chime in and confirm or deny this.
Runways are re-paved quite often. That’s the only thing you can do to stop potholes, cause water gets in, freeze, and the ice breaks it apart. Repeat for some years and entire chunks will detach. When you re-pave you fill those gaps with new tar, preventing further deterioration.
This said, a runway is generally a gigantic concrete slab with tarmac on top. It’s not built like roads. If you drive a big plane on a road full load, it would sink in the road. We are speaking of 10-30ton per individual wheel.
Runways are re-paved quite often. That’s the only thing you can do to stop potholes, cause water gets in, freeze, and the ice breaks it apart. Repeat for some years and entire chunks will detach. When you re-pave you fill those gaps with new tar, preventing further deterioration.
This said, a runway is generally a gigantic concrete slab with tarmac on top. It’s not built like roads. If you drive a big plane on a road full load, it would sink in the road. We are speaking of 10-30ton per individual wheel.
I don’t have any specialized knowledge, but I saw some runway construction at an airport once and the concrete appeared to be several feet thick instead of the several inches thick concrete used in highways. It’s been quite a few years, but I remember the concrete being roughly as thick as a man is tall.
Hopefully a civil engineer will chime in and confirm or deny this.
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