

Using Non-Newtonian Fluids to Fill Potholes - dclaysmith
http://news.sciencemag.org/sciencenow/2012/04/silly-putty-for-potholes.html

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barrkel
I wonder about grip properties, particularly for motorcycles while cornering.
A bag that shifts position, even a little, may be dangerously destabilizing.
As it is, manhole covers need to be avoided when wet (and best avoided in
sharp cornering in the dry too).

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quinndupont
Or cyclists! I wonder what would happen if a relatively slow moving, thin
wheel rolled over this? I'm worried that a cyclist would sink in to the
material, and be well on their way to a header.

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dgallagher
Maybe it would work better on an interstate, particularly flat sections, where
there are no cyclists, and vehicles are constantly moving forward at high
rates of speeds? Warnings could be posted to warn motorcycles not to swerve
(e.g. like uneven surface warnings).

And to deter slow-pokes, entire sections of highway can be filled 100 feet
deep with the stuff. If anyone slows down too much, the highway sarlacc
acquires a tasty meal.

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tocomment
I've always wondered if you could use non-newtonian fluids for speed bumps? So
if you drive under a certain speed, the fluid just moves away and you don't
feel a bump. But if you go too fast it hardens and you hit the bump.

I.e., if you go slow you don't feel the speed bump.

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nisse72
You mean like this?

[http://www.gizmag.com/bumpfree-dynamic-speedbump-gives-
you-a...](http://www.gizmag.com/bumpfree-dynamic-speedbump-gives-you-a-smooth-
ride/14156/)

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apinstein
How dangerous is this when the patch somehow pops out (or is removed by kids)
and sits in the street? When you run over a 12" bag of shear-thickening fluid,
does it turn into a rock and destroy your car?

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wtallis
I doubt it could be any more dangerous than the pothole, since the patch would
spread out to be as thin as the bag allows, making it into a thin lump on the
road that would be no more likely to fly up and damage a car than loose pieces
of pavement around the edge of the pothole.

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EvilTerran
What happens if you park with a wheel resting on one of these, though? Would
you come back to find your tire had sunk in?

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StavrosK
Not just park, I'm guessing it'd take a few seconds of rest for your wheel to
sink in it. I guess it'd probably rip the bag and sink in the hole completely.

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DEinspanjer
Nyah, I guess that the reason they went for tough kevlar bags is to be able to
withstand the weight of the care. I think it would sink a bit but cause any
damage or pose a hazard to the car.

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overcyn
Why wouldn't a bag of sand or gravel work similarly? It's less viscous but
pouring gravel into a hole and covering it can't take that much longer.

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tmh88j
Viscosity isn't what matters. Sand and gravel do not harden when force is
applied and will spread apart as I'm sure you can imagine.

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StavrosK
They're already hard. They won't spread apart because they're in a hole.

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DEinspanjer
The individual pieces may be hard, but the collection is not. Think about
walking in the sand. Your feet sink down and the sand will flow up and over
the sides of a container. Gravel is the same way albeit to a lesser degree
because the pieces are larger.

With a sheer-thickening fluid, when sheer force is exerted on it, the entire
collection of fluid affected by that force hardens in reaction so it would be
like running over the top of a bag of hardened concrete.

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StavrosK
You're assuming there's a large surface of it. There's a rigid container for
the little bit of sand (the pothole). Filling it with gravel works very well
(we do it a lot in Greece as a temporary measure). The problem is that the
gravel gets thrown out of the hole bit by bit by cars, but the solution in the
article isn't meant to be permanent either.

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papalalu
a liquid will return to a flat hole-filling shape if it's altered, gravel does
not. Also not great to spread gravel around your road, especially if it's used
by bicycles. Gravel also hinders repair work

I also like the idea that the bag could be coloured to assist cyclists in
avoiding them..

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jmount
I would imagine that traditional pitch/tar (being a big bag of long molecules)
is itself already a non-Newtonian fluid (is temporarily harder under impact).
See <http://en.wikipedia.org/wiki/Pitch_drop_experiment> for why you can
consider pitch a very viscous fluid.

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beefman
Good idea. But how about filling potholes with a Newtonian solid, like
asphalt? It isn't terribly hard to do. I'm reminded of Peter Thiel's recent
comment:
[http://www.youtube.com/watch?v=XRrLyckg8Nc&#t=58m38s](http://www.youtube.com/watch?v=XRrLyckg8Nc&#t=58m38s)

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dclaysmith
I could see where a slightly more robust solution could really work. Lay down
a film (thin-ish plastic/spray sealant that would create a semi-sealed pool on
the bottom of the pothole), then fill in liquid from a tank, then apply an
epoxy on edges and then a kevlar mesh on top. Then you'd have a decent
surface. Especially if the liquid was more like a "gel".

I'm not an engineer or a scientist--there are likely loads of reasons the
above is impractical.

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Retric
Well, actually filling the pothole is simpler and cheaper. A hot patch costs
around 1,900$ and lasts a reasonably long time depending on what caused the
problem in the first place it can literary be 10 years before the problem
shows up again.

[http://www.chicagotribune.com/classified/automotive/traffic/...](http://www.chicagotribune.com/classified/automotive/traffic/ct-
met-0326-getting-around-gfx.eps-20120325,0,7076245.graphic)

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cantbecool
I wonder if this fluid is similar to a commerical product that has been
publicly available for a few years, D3o. <http://en.wikipedia.org/wiki/D3o>

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aiscott
It's an interesting idea; I look forward to seeing how it turns out in the
longer term.

I'm sure this would never be sanctioned but I think it would be great if
people could temporarily patch these damn things on their own rather than
waiting for the government to get around to it.

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amalag
This company uses infrared technology to patch potholes, instead of
traditional asphalt. They are selling franchises. The owner of a company I
used to work for bought the franchise for MD-DC-VA and is doing well with it.
<http://www.bpotholefree.com/>

