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Pavement
Mon Jan 31, 2005
Listen in RealAudio 
Building and patching roads isn’t as simple as slapping down asphalt over some dirt.
The soils for yards underneath affect the integrity of the surface. Hi, I’m Bryan Yeaton
for The Weather Notebook.
Steve Flanders is the chief of the Civil and Infrastructure Engineering at the Cold
Regions Research and Engineering Laboratory:
Well, our branch has a number of specialties that include traditional civil engineering of
roadways and buildings, but it encompasses other types of infrastructure, including
buried utilities, for instance.
What’s under the pavement is important because when moisture in the soils freezes, it
can really wreck a road.
The good part about having this building is we can do up to six freeze-thaw seasons
every year that draws moisture up from the water table, creates frost -- frost lenses that
are what causes the frost heaves -- and, of course, ultimately causes the thaw
weakening and the soggy roads ... if you’re talking about an unsurfaced road in
springtime.
And then, there’s the HVS.
That large, long blue thing is our heavy vehicle simulator and the idea is not just to
build a road but to test how loads are transmitting down through wheels into the soil.
And the way we can do this in a very predictable, and many times repeated, fashion is
to use the heavy vehicle simulator and we can apply loads that resemble truck loads --
and those are the most challenging loads for a road to bear -- or we can change the
tire and put an aircraft tire on it.
How many circuits does it make, say, in a day?
We can do up to 15,000 repetitions per day.
Something to think about as you curse along that bumpy road. They are working on it!
The Weather Notebook is supported by Subaru of America.
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