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Transparent Concrete
rakerman writes: "The Economist reports in How to see through walls that development is underway on translucent concrete, with hopes of eventually developing transparent concrete. Can transparent aluminium be far behind?"
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Apparently neither The Economist nor Slashdot knows the difference between translucent and transparent. Ugh.
Anyway, this is old news. Metropolis magazine reported on the development of translucent concrete back in April 2001.
Such a material already exists--in fact it predates human civilization. It's called Al2O3, or alumina, and more commonly known as sapphire (or it's chromium-doped cousin, ruby). It has a hardness of 9 out of 10 on the Mohs scale (the only harder material I know of is diamond) and is transparent in the absence of impurities. However, it is not an alloy--it's a crystalline oxide.
Metallic aluminum cannot be transparent except in thin films; this will be explained in a reply to the top-level post in this thread.
"It take 9 months to bear a child, no matter how many women you assign to the job."
although right now it sounds more like Plexi glass or a liquid epoxy of some sort. kudos to the marketing rep who associated it with concrete.
on the other hand, at my old middle school, the school had outgrown it's original gym, and elected to build a second gym away from the main building, made entirely from concrete. I never understood how that thing stood; it was full-sized, housed a cafeteria in one end, and above that was the wrestling mat. to get to the point, it was abysmally dark in there. they had xeon HID lamps or the likes in there, and things were still pretty dim. emergency lights would no doubt have poorly lit it also. making the east and west walls semi-translucent would have significgantly improved lighting conditions.
i wonder if you could put an element in this "concrete" that would block IR light, otherwise I can't see this being implimented in the south or very far north, as it would cause massive heat-loss/absorbsion.
moox. for a new generation.
Buildings glowing from within? This is terrible for astronomers... the added light pollution would further ruin the viewing conditions for many great observatories.
"I would say that 99 per cent of what my father has written about his own life is false." - L. Ron Hubbard Jr.
It has been my understanding that all metals must be the color they are, because of the way electrons swim around in the metal meta-crystal, and the way they interact with hitting photons.
If this understanding of mine is correct, transparent aluminium (or any other metal reinforcement) is not likely to happen, but some sort of plastic may do the trick.
The explanation on how to achieve this reads a bit funny.
It seems to assume that if one mixes two transparent
components (e.g. glass grid, and some transparant matrix), the result is also transparent.
This is not true, as every high school boy that studied optics can tell you. Refraction index, surface properties etc.
It will probably be pretty hard to make a transparant material from two components, let alone keep the other properties of concrete.
The article mentions that the doctor wants the material to be able to recycle. The author comments that this might be a "tall order".
This tells me they must be using some VERY uncommon bonding agent. They do mention the use of glass, which is a sand product anyway, being used.
It's hard to imagine why they couldn't recycle this stuff like they recycle concrete now. It makes me even more curious as to what their formula is.
. Quit playing Monopoly with Bill. Switch to one of many non-Microsoft products today.
The quest for transparent buildings is eternal among deigners, eternally rejected by building occupants (for the most part). After all, who *really* wants transparent waste lines? Not to mention walls are not uninterupted monolithic entities-there are all sorts of utilities in walls. As a *real* architect ("brick and mortar"), I've seen this sort of fad before, but it is hideously expensive to achieve and can only be done in specialized buildings, not general use. Not to mention, these types of buildings often do not weather well.
No - it's not as if the concrete is as clear as glass. During the day, when bird strikes are most common, the material will look fairly opaque, maybe slightly translucent(like those fiberglass greenhouse shed roof panels) but nothing like glass. On the inside, it will appear to be much more translucent since light is penetrating an otherwise dark surface(without the aid of extra lighting).
And we really need to get over bird strikes as a reason to NOT do something beneficial to the environment IE wind power, transparent structures that need less electrical lighting, etc. The simple fact of the matter is that more birds would be killed by pollution than would be killed by introducing new technologies that use less energy(or generate energy for FREE)
Wouldn't the steel tank have been much heavier?
GreyPoopon
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Why is it I can write insightful comments but can't come up with a clever signature?
Don't see it mentioned anywhere in the comments yet, but after reading the article, the first thing that concerned me is that the nice thing about a concrete building is that it will hold together when it catches fire, not melt, puddle, and add to the blaze with choking poisonous smoke.
Hopefully the designer is taking into account other properties besides strength.
-- perl -e'print pack"H*","6e656d6f406d38792e6f7267"'