Using Non-Newtonian Fluids to Fill Potholes | Hacker News Reader

Using Non-Newtonian Fluids to Fill Potholes

news.sciencemag.org

121 pointsdclaysmith30 comments

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).

I was wondering the same thing. I was a little concerned about the adhesive fabric cover that they put over the bags. What happens if that happens to slip underneath your motorcycle tire halfway through a turn? IN the video the adhesive fabric moves way to much for me to be comfortable riding over it. I was also surprised that they just went out and threw it in a pothole in Cleveland somewhere. Is that allowed? Real world live tests of prototype products on the street.

The article states at the end that the city has offered to help them test it. It is pure speculation but maybe they had already helped by giving permission to test on the potholes mentioned earlier in the article.

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.

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.

The article mentions that it is intended as a stop-gap measure until proper repairs can be performed. So I think that as long as it is less destabilizing than the pothole itself, it serves its purpose.

I'd be less concerned except that they take pains to say that the bags should be coloured the same as the road, so that drivers don't take any action to avoid them. But motorcyclists depend on road surface that looks good, being good.

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.

You mean like this?

http://www.gizmag.com/bumpfree-dynamic-speedbump-gives-you-a...

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?

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.

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?

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.

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.

I was thinking along the same lines. If, for instance, a car is stopped on top of the bag in traffic, or at a red light, then I imagine accelerating while on the bag could cause potential ripping, or depending on how deep the hole is, it could pull the bag right out, leaving it as a hazard for other cars. Not to completely discount this idea though, because I do think it's quite innovative.

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.

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.

Dirt roads? gravel roads? And the bag keeps it together. But I'm also not a civil engineer so I'll take your word for it.

The bag will rip and tear over time because the contents are shifting independently of each other. This will not happen (as quickly) with a non-Newtonian liquid. Not to mention, dirt and gravel roads aren't big bags. The materials are simply laid out on the ground. They also don't last very long under high traffic or heavy loads.

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

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.

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.

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..

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.

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

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.

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/...

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

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.

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/

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