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Is Our Infrastructure Ready For Rising Temperatures?
Hugh Pickens writes "Megan Garber writes that last weekend, a US Airways flight taxiing for takeoff from Washington's Reagan National Airport got stuck on the tarmac for three hours because the tarmac had softened from the heat, and the plane had created — and then sunk into — a groove from which it couldn't, at first, be removed. So what makes an asphalt tarmac, the foundation of our mighty air network, turn to sponge? The answer is that our most common airport surface might not be fully suited to its new, excessively heated environment. One of asphalt's main selling points is precisely the fact that, because of its pitchy components, it's not quite solid: It's 'viscoelastic,' which makes it an ideal surface for the airport environment. As a solid, asphalt is sturdy; as a substance that can be made from — and transitioned back to — liquid, it's relatively easy to work with. And, crucially, it makes for runway repair work that is relatively efficient. But those selling points can also be asphalt's Achilles heel. Viscoelasticity means that the asphalt is always capable of liquefying. The problem, for National Airport's tarmac and the passengers who were stuck on it, was that this weekend's 100+-degree temperatures were a little less room temperature-like than they'd normally be, making the asphalt a little less solid that it would normally be. 'As ironic and as funny as the imgur seen round the world is, it may also be a hint at what's in store for us in a future of weirding weather. An aircraft sinking augurs the new challenges we'll face as temperatures keep rising.'"
Tarmac is formulated for specific climates, so that it heats and flows properly for the maximum temperature expected in that area. For instance, 25 years ago in the region where I live, a Hot day was around 80 degrees. So the asphalt mix used was intended for that sort of climate. Now that our summers mave many days in the mid-upper 90's, and a few that tweak 100, that asphalt is out of it's temperature range.
The reason that they use different mixes depending on climate is that the mixes that set will in a cooler climate, also have some resistance to frost heaving. The mixes that harden at a higher temp are more brittle at freezing temps.
This is probably more than anyone wants to know about asphalt paving or tarmacadam.
Otherwise, yeah, we are sure letting a lot of stuff fall apart.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Damnit, even the worst fearmongers tell us that temperatures will rise by 1 degree per 20 years. Even ignoring the fact that this kind of temperature rise is insignificant in terms of what we're talking about, that's decades or centuries to replace infrastructure.
Instead of worrying about asphalt on streets, I'm worring about brains already having melted in one-too-many climate change activists demonstration.
Get a clue.
"Temperatures will rise by an average of 1 degree" does not imply that temperatures will be ~1 degree higher each and every day. Quite the contrary, climatologists predict that the weather (including temperature) will be MUCH more volatile. That means you will have many days where the temp is >15 degrees above normal, in additional to crazier winter weather etc.
Basically, because the size of weather fluctuations are expected to increase, you will get more days of crazy temperatures that will take a toll on infrastructure.
In the US, you can always tell the tollways from the freeways -- they're far less well maintained, as the private businesses which own them are interested in extracting as much profit as possible. Since there is no cost incurred from the delays, accidents and/or deaths caused by the poor road quality, the businesses simply don't bother with maintenance. It's the invisible hand of the market at work, not giving a flying fuck about the externalities.
Tubal-Cain smokes the white owl.
Actually you have it the wrong way around. Most runways are asphalt with concrete landing areas while taxiways are concrete so aircraft can sit on them or long periods of time. Asphalt is used because it does not have expansion joints and is less susceptible to heaving. Here is an example of a USAF airfield with just that configuration. Note that the taxi ways are a light colour while most of the runway is dark. In the text it explains exactly what kind of asphalt was used. Here is another example in Alaska. Notice that the aircraft are sitting on concrete while most of the rest of the taxiways and runways are asphalt.