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Science Technology

Transparent Concrete 361

Posted by michael
from the mandated-by-anti-terrorism-act-of-2004 dept.
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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Transparent Concrete

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  • by Eharley (214725) on Monday January 28, 2002 @03:47AM (#2912570)
    Won't translucent structures lead to an increase rate of smack death amongst bird populations?
  • Hmm... (Score:4, Informative)

    by Drakin (415182) on Monday January 28, 2002 @03:53AM (#2912578)
    Well, it's nice to see innovation within the construction sector isn't dead. Even for something that seems so off the wall as transparent (or currently, translucent) concreat can give birth to innovative new designs and possibilities from architechs.

    I mean, I can just see a wall done with a bubble effect (with slighly differnt opacities in the aggitates and clear binding coumpound).

    Only thing is, once transparent concreate is perfected... how are the mobsers going to get rid of bodies if they can't throw them in the foundation of a new building anymore...
  • by Hal-9001 (43188) on Monday January 28, 2002 @03:55AM (#2912587) Homepage Journal
    They're called windows, and they're usually made of a neat transparent material called glass... ;-)

    Seriously, though, any slurry-based material like concrete is most likely to be opaque because microscopic structures tend to scatter light. You only need to pour a glass of milk to see this in action.
    • Some people (*cough*moderator*cough*) have no sense of humor and don't know anything about the subject they're moderating... :-p
    • And each window needs to be constructed elsewhere, shipped, and placed in a hole that is sunk in a wall after the wall is in place. In conrete construction, this entails a good deal of work to do successfully and the benefits to doing so are limited. In fact, in doing so, the insulative value of concrete is often lessened. By having a "window" of transparent concrete, our structure sacrifices less of its insulation and the work required to place them is lessened. Furthermore, transparent concrete would allow for even more artistic placement of windows in modern architecture, since the window could be load-bearing.

      Even if the engineers only managed to make the concrete translucent, it would still be of some advantage.
    • by Pathetic Coward (33033) on Monday January 28, 2002 @08:32AM (#2913106)
      Windows is a trademark of Microsoft Corporation.

      Please use the term "transparent exterior access devices".
      • It's a conspiracy I tell you!!!

        Microsoft have been developing transparent concrete for a while now..

        fine aggregate = Windows CE
        course aggregate = Windows ME
        binding agent = Windows NT

        Mix them all together and you get

        Microsoft CE-ME-NT
  • Transparent aluminum (Score:4, Interesting)

    by digitalunity (19107) <digitalunity&yahoo,com> on Monday January 28, 2002 @03:55AM (#2912588) Homepage
    I seriously doubt we will ever see transparent aluminum. In order for it to succceed, the atoms would have to be aligned in a crystaline matrix. Such a matrix would likely create a hard, yet weak substance.

    It would have much strength, yet it would fracture easily. Its called "Modulus of elasticity"; something certain steels(H11 namely) holds in spades. I doubt even if it could be produced, people would find it of much use.
    • by GoRK (10018)
      Well, we already know the best use of it is to put windows in our starships. (heh) But even the starship windows are actually an aluminum alloy.

      [For those of you missing the whole joke -- the windows on the spaceships in Star Trek are supposed to be "transparent aluminum"]

      Pure transparent aluminum might be weak indeed, but perhaps it can be used in an alloy to create a transparent sheet that is as strong and durable as oridnary sheet aluminum. I find it hard that you mention steel (in particular certain varieties) yet you fail to address the usefulness of a transparent aluminum component in such an alloy.

      Heck, even laminating something ordinary (ie lucite, glass) with such a material would have immediate benefits. Think diamond-tipped bits, saws, etc.

      ~GoRK
      • by Hal-9001 (43188) on Monday January 28, 2002 @04:13AM (#2912623) Homepage Journal
        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.
        • Are you calling Star Trek IV a thin film?

          I thought it was quite profound. Save the whales and all that...
        • Hardness and fragility are two different things. Glass is hard but fragile, as are diamonds. Perspex isn't hard, but is flexabile, which is why it's used for aircraft windows. Unfortunatly this means that every so often the windows have to be polished so that they remain transparent. An ideal substance for windows would be both hard (so that it doesn't scratch) and flexabile (so that it can take knocks).
        • It might be possible the take a bunch of really thin threads of aluminum and weave them into a mat, which you then embed into a matrix of pale sapphire. Perhaps the metalic threads would enhance the flexibility of the sapphire, while still being thin enough to allow for transparency. The problem that occurs to me is that I believe that sapphire usually solidifies at a higher temperature than aluminum. So keeping the mat intact might be a real challenge.
          .
    • by Hal-9001 (43188) on Monday January 28, 2002 @04:35AM (#2912665) Homepage Journal
      The reason you will never see transparent aluminum is not because of a lack of crystalline structure--in fact, I think metals generally are crystalline or at least have a crystalline microstructure. The reason that aluminum, and basically all metals, are opaque is the same reason that metals tend to be shiny. Because there are a lot of free electrons in metals (which is why they conduct electricity well), the electric field of light expends energy driving these free electrons (therefore metals are opaque), which in turn reradiate light back in the direction of the incident light (therefore metals are shiny). The amount of light that gets through goes as e^-ax where a is a constant and x is the thickness of the metal, so in a very thin metal film (e.g. mirrored sunglasses) you can still get some light through, but for any measurable thickness of metal (e.g. aluminum foil and anything thicker), the amount of transmitted light is negligible.

      I know this is a very hand-wavy explanation, but it's hard to explain without a pretty advanced background in electromagnetics. If you want an explanation of this from a rigorous electromagnetic point of view you can try wading through Chapter 14 of Principles of Optics by Max Born and Emil Wolf, but its mostly math with very little physical intuition or explanation.
      • Are you sure? (Score:2, Interesting)

        by supernova87a (532540)
        I have to agree here -- I don't think that crystalline structure alone will confer transparency on a material, especially metal. It has firstly to do with the properties of the atoms and molecules themselves, and maybe second the crystalline nature.

        Why, then, would glass be transparent? Glass has a most uncrystalline structure!
        • I have to agree here -- I don't think that crystalline structure alone will confer transparency on a material, especially metal. It has firstly to do with the properties of the atoms and molecules themselves, and maybe second the crystalline nature.

          Why, then, would glass be transparent? Glass has a most uncrystalline structure!
          Doh! Why didn't I think of that obvious counterexample? ;-)
      • Yes, metals have a crystalline microstructure. However, not all metals are aligned into a full crystalline matrix. The best example of this is cast versus forged aluminum. Under high magnification, you can observe the alignment of a forged sample and the relative disorderliness of a cast aluminum sample.

        Also, one very good example of opaque or transparent metal is any professionally chromed auto part. Any real chroming process follows like this:

        Polish to a very low RA(Roughness Average). The lower, the better. Electroplate a few thousandths of nickel. This is what makes 'chrome' shiny. The chrome itself is merely a hard shell. The nickel is what is really doing the reflection. After the chrome is electroplated, repolish. Done. Mirror finish.

        If any of these examples are difficult to understand, I apologize. My main area of studies is automotive technology. That is what I am most familiar with.
      • by markmoss (301064) on Monday January 28, 2002 @10:12AM (#2913482)
        I'll try to re-state Hal-9001's post in a little different form:

        Electromagnetic waves consist of oscillating electric and magnetic fields in alignment so as to be self-perpetuating. The changing magnetic field creates an electric field a little further on, and the changing electric field creates a magnetic field still further on, etc.

        First consider a radar beam approaching a metal surface. The E-field will cause the free electrons in the metal to move. This transfers the energy of the beam into electron motion. And with several pages of math that I went through once and never want to again, it can be shown that the electrons move so as to create a mirror-image field, re-transmitting the beam at the angle of incidence -- in other words, a reflection.

        Due to resistance to electron movement, the reflected beam will be somewhat weaker, the missing energy being absorbed as heat. If the metal is extremely thin there might not be enough free electrons to fully absorb the incident beam, so part of it passes through. In an insulating material, electrons are tightly bound to molecules, and so cannot range far enough for strong interactions with the beam, and so most of the beam will pass through (the material is "transparent" to radar). However, electrons can shift around within the molecules, which causes refraction, partial reflections, and absorption.

        Things are different for x-rays, because the individual photons are pretty energetic and the wavelength (size of one photon) is close to the size of an atom. So it's more likely to be the inner electrons still bound to the atoms that wind up trying to capture the x-ray, and only rarely does this succeed -- most of the x-rays get through several inches of all but the densest materials.

        Visible light photons are in-between in size, large enough to interact well with the free electrons (reflection), but small enough to also be affected by bound electrons. (Selective absorption by the bound electrons gives copper and gold their color.)

        Most insulators are not transparent to visible light, except as very thin films. Most insulators (like metals) consist of irregular aggregations of tiny crystals. The interactions with the electrons bound in molecules will reflect some light, absorb some, and refract all the rest. In most insulators, the interaction varies with the polarization of the photon and the angle of the crystal; since each crystal is oriented differently, each interface between crystals refracts and reflects light in different directions, so the light that isn't reflected from the external surface is scattered and (mostly) bounces around inside the material until absorbed rather than passing through.

        Most transparent materials are glasses, with no crystal structure, and so no grain boundaries to scatter the light. Single crystals may also be transparent, although it's pretty hard to grow a single crystal as big as a windowpane. Multi-crystalline insulators can be translucent if sufficiently free of the atoms or molecules that absorb light, that is if the light is scattered but not absorbed eventually it will find it's way back out of the material. Concrete could be translucent if both the aggregate and the cement were free of light-absorbing materials, but I think the price would be extremely high.

        Possibly a multi-crystal insulator could be transparent if the refractive index did not depend on orientation of the crystal or polarization of the light, and if all the crystals fit together neatly and had the same refractive index. Or use glass beads for aggregate and somehow make the cement match the glass?

        Metals by definition have free electrons, which strongly reflect and absorb visible light. If it's transparent, it's not a metal.

        You can form Al2O3 into fairly large crystals, and maybe it could be a glass too. It's stronger and much harder than silica-based glass, so it would make a great windshield, if you didn't mind the cost of using diamonds for cutting and polishing.
      • Question - could you make aluminum transparent on some wavelengths by packing it with an array of voids of size comparable to a wavelength of light?

        If I understand correctly, this will allow light of a matching wavelength to pass through.

        OTOH, if it's more than a few wavelengths thick, it will be very frequency-selecive, so you'd still block virtually all light. And building this extrememely ordered structure is left as an exercise for the reader. I'm just wondering if this or similar patterning would work.
        • What you describe sounds like a photonic bandgap material. I have not heard of metal photonic bandgap or multilayer structures, and therefore, I am not sure whether there is a physical limitation that makes them either impossible or just very difficult to make. You are correct in stating that such a structure would be very frequency selective, and so to the naked eye it still wouldn't look transparent, , but I would also be very curious if something like this could operate at a specific wavelength.
      • The reason you will never see transparent aluminum is not because of a lack of crystalline structure...

        The real reason you will never see transparent aluminum is because it is, well, transparent.
    • by cowbutt (21077) on Monday January 28, 2002 @05:57AM (#2912809) Journal
      I doubt even if it could be produced, people would find it of much use.

      I dunno. I find it invaluable for transporting live whales in my time-travelling starship, complete with enough water to for them to move around in.

      I could use steel or something, but, darn, I like to press my nose up to their enclosure during the journey.

      --

      • by jea6 (117959)
        Sorry guys. Transparent Aluminum wasn't available in the 20th Century. Scotty traded Plexico the formula for transparent aluminum for the standard six inch plexiglass:

        "SCOTTY
        Doctor Nichols, I might have
        something to offer you.

        NICHOLS
        ... Yes?

        SCOTTY
        I notice you're still working with
        polymers.

        NICHOLS
        (mystified)
        Sill? What else would I be working
        with?

        SCOTTY
        Ah, what else indeed? Let me put it
        another way: how thick would a piece
        of your plexiglass need to be at 60
        feet by 10 feet to withstand the
        pressure of 18,000 cubic feet of
        water?

        NICHOLS
        That's easy: 6 inches. We carry
        stuff that big in stock.

        SCOTTY
        Yes, I noticed. Now suppose -- just
        suppose -- I could show you a way to
        manufacture a wall that would do the
        same job but was only an inch thick.
        would that be worth something to
        you, eh?

        NICHOLS
        ... Are you joking?

        BONES
        He never jokes... Perhaps the
        professor could use your computer.

        [...]

        NICHOLS
        (wide-eyed)
        Transparent aluminum?

        SCOTTY
        That's the ticket, laddie.

        NICHOLS
        ... But it would take years just to
        figure out the dynamics of this
        matrix...!

        BONES
        You'll be rich beyond the dreams of
        avarice.

        SCOTTY
        So, is it worth something? Or
        should I just punch "clear"...

        NICHOLS
        No!
        (then)
        No... What did you have in mind...?"

        Live long and prosper.
    • I seriously doubt we will ever see transparent aluminum. In order for it to succceed, the atoms would have to be aligned in a crystaline matrix. Such a matrix would likely create a hard, yet weak substance.

      This post is rather amusing when you know that:

      1. most metals as we know them have a crystalline form, except maybe mercury as it's liquid at usual temperatures, and

      2. glass is NOT crystalline, and yet is the first thing we think of when we think of a transparent material.

      3. plastics, which are the second thing we think of, are not crystalline either, they're polymers, id est long chains of molecules.
  • by mmontour (2208) <mail@mmontour.net> on Monday January 28, 2002 @03:56AM (#2912590)
    Can transparent aluminium be far behind?

    It's already here [guildoptics.com], although in the form of an oxide rather than the pure metal.
  • by btempleton (149110)
    A little off topic, but germane to the item noted in the summary for this topic.

    He refers to transparent aluminum from the Star Trek IV movie. In that film, they risk rewriting history by giving the technology for transparent aluminum to a 20th century factory.

    They never answer the basic question of why did the aluminum have to be transparent? Why not regular aluminum or any other such material? Do the whales need a view of the Klingon starship? Do they have no cameras or sensors to let them see the whales?

    It made no sense at all but it was a major plot point for the whole film. Sigh. Ok, mod me off topic now.
    • by syrinx (106469)
      no no no. they needed *something* to keep the whales in. all they could get was plexiglass. they had no money to pay for the plexiglass. so they gave the guy the forumla for transparent aluminum in exchange for the plexiglass. the factory didn't suddenly start churning out sheets of transparent aluminum (the guy says something like "it would take years to figure out blah blah blah" to which scotty says "yeah but you'll be wicked rich").
      • You'll be rich beyond the dreams of Avarice!
      • Daresay this is alomst as silly. Changing history in a major way to raise some money? If people came in and offered an invention worth hundreds of millions to get a few thousand dollars worth of plexiglass in a rush, I can't see anybody going for it no matter how good it looked in the computer models.

        There are so many other ways they could have raised cash than this (or selling eyeglasses.)

        Not the first time this strange plothole shows up in an SF movie, since we saw it again in Star Wars 1, where a Jedi with all his mind powers couldn't find anybody in a whole city who might trade him imperial credits for local currency.

        (Note, fun watching how the moderation has gone up and down on my original post!)

  • "Can transparent aluminium be far behind?"

    Yes, transparent aluminum can be far behind. Metals like aluminum have free electrons which prevent transmission of light.
  • by bradlauster (118086) on Monday January 28, 2002 @04:05AM (#2912611) Homepage
    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 [metropolismag.com] back in April 2001.

  • by heretic108 (454817) on Monday January 28, 2002 @04:07AM (#2912616)
    would be to legislate that all new residential and commercial dwellings be built from transparent concrete.
    Anyone refusing to demolish their existing house would be added to a database of 'potential conspirators'.
    This would be quite consistent with recent 'anti-terrorist' surveillance legislation.
    Also, the boom in building would boost the flagging economy.
    Imagine whole neighbourhoods of people living in complete exposure, proving they're real honest patriotic Americans.
    • by jabber01 (225154)
      "We" [amazon.com] by Yvegeny Zamyatin, written in 1927, is a precursor of Orwell's 1984. It's a classic dystopic novel, which features, among other things, transparent dwellings for exactly the purpose you suggest.
  • by iangoldby (552781) on Monday January 28, 2002 @04:10AM (#2912620) Homepage
    I wouldn't want to live in a transparent house. Think of the lack of privacy. People'd be able to see when I was in the bedroom, when I was in the bathroom... They'd be able to see all my movements.
  • interesting idea (Score:2, Insightful)

    by Hadlock (143607)
    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.
  • by Osty (16825) on Monday January 28, 2002 @04:14AM (#2912628)

    There is a very big difference between "transparent" and "translucent". The former means that light passes through the material almost completely unchanged (a certain amount of distortion is okay, but the point is that you can make out what's behind it). Translucent means that light is transmitted, but it's diffuse and you can't make out what's behind the material. This concrete is translucent. It's not transparent (read the article).

  • by Hougaard (163563) on Monday January 28, 2002 @04:17AM (#2912635) Homepage Journal
    The real problem with transparent building materials is that people inside want to control the transparency, just look at your own home, you got curtains and shades on all(most) windows.

    A classic problem with new hightech buildings (Glass 'n metal) is climate control, its nice to be able to look outside, but if the sun is starring you right back its not that fun. So you tint the windows :)

    The next problem is that in those buildings the light that gets through is not white light (sunlight) anymore, and working in that kind of buildings can cause depressions very similary to winter depressions.

    Remember: Architects are just building nerds :)
    • by Hal-9001 (43188) on Monday January 28, 2002 @05:25AM (#2912761) Homepage Journal
      It's a shame that electrochromic windows [nrel.gov] haven't taken off. I first read about them in Popular Science, probably about 10-15 years ago, and if I recall correctly, they were used in a concept car by Ford (I could be mixing two Popular Science articles together), but they allow you to electrically darken and lighten windows, and they actually reflect light and heat (unlike liquid crystals, which just scatter light and heat but still let them through). I'm not sure, but they might also be wavelength-independent, i.e. reflecting all colors of light equally. The obvious barriers to their widespread adoption are probably cost and the ability to make panes large enough to use as windows.
      • by swb (14022)
        I think by either Marvin or Pella. I've seen promotional materials, and IIRC it was a kind of transparent LCD panel that could be opaqued or made mostly transparent. The downside is that I believe it took power to keep the window transparent, and it was really expensive.

        Either way, modern windows, according to my wife who used to work with Andersen Windows, have a higher R factor than a lot of walls -- triple glazing, low emissivity coatings, and krpton/argon filled voids go a long way.
  • by Eminence (225397) <akbrandt&gmail,com> on Monday January 28, 2002 @04:19AM (#2912640) Homepage

    Can material described in the article really be called "concrete [britannica.com]"?

    As it is written there its only resemblance to concrete is that it consists of coarse aggregate, fine aggregate and binding agent. But this is not a recipe for concrete only - also for other materials. Also, Dr. Price's secret material can't be poured or produced on site - one the main reasons of traditional concrete popularity. It would probably find its use in form of blocks of translucent material, that could be used to enhance possibilities for architects but what Dr. Price is trying to do is another building material, which is very interesting indeed but can hardly be called "concrete".

    • by Hal-9001 (43188) on Monday January 28, 2002 @05:11AM (#2912737) Homepage Journal
      From the story:
      Technically, concrete is simply a mixture of three ingredients: big lumps of material called the coarse aggregate (such as gravel), smaller lumps called the fine aggregate (such as sand) and a binding agent, or cement, to glue it all together into a solid. So translucent concrete, in theory, should be fairly easy to make using bits of plastic or glass of various sizes, with some kind of transparent glue to act as a binding agent.
      This sounds more like a composite than concrete to me. The Dictionary of Composite Materials Technology [about.com] defines a composite [about.com] as
      A multiphase material formed from a combination of materials which differ in composition or form, remain bonded together, and retain their identities and properties. Composites maintain an interface between components and act in concert to provide improved specific or synergistic characteristics not obtainable by any of the original components acting alone. Composites include: (1) fibrous (composed of fibers, and usually in a matrix), (2) laminar (layers of materials), (3) particulate (composed of particles or flakes, usually in a matrix), and (4) hybrid (combinations of any of the above).
      By this definition, "transparent concrete" is a particulate composite of plastic or glass, probably in a matrix of epoxy or resin. Concrete is also a composite by this definition, but despite what my civil engineering friends might try to tell me, that doesn't mean that all composites are concrete. ;-)
    • by Anonymous Coward on Monday January 28, 2002 @07:51AM (#2913001)
      Edible concrete has been with us for years:

      coarse aggregate - dried fruit
      fine aggregate - flour
      binding agent - eggs.

      It proved so popular, it's got its own name - cake!

      Let's face it, Marie Antoinette would've looked a bit of a dork saying "let them eat edible concrete."

      • An AC wrote:

        Edible concrete has been with us for years:

        coarse aggregate - dried fruit
        fine aggregate - flour
        binding agent - eggs.

        It proved so popular, it's got its own name - cake!

        Let's face it, Marie Antoinette would've looked a bit of a dork saying "let them eat edible concrete."

        I haven't any real mod points, but this AC post deserves notice in the context.

        -- MarkusQ

    • I would be willing to stretch the definition to include this new material... IF it is also structural.

      Hm, tastes like concrete.

      Hm, feels like concrete.

      Hm, The way this bridge is wobbling makes me think maybe it's not real concrete.
    • But this is not a recipe for concrete only - also for other materials.

      Yes, it is also a recipe for meatballs.
  • Light Pollution (Score:4, Insightful)

    by zephc (225327) on Monday January 28, 2002 @04:25AM (#2912649)
    Buildings glowing from within? This is terrible for astronomers... the added light pollution would further ruin the viewing conditions for many great observatories.
    • by foobar104 (206452) on Monday January 28, 2002 @10:08AM (#2913467) Journal
      Buildings glowing from within? This is terrible for astronomers... the added light pollution would further ruin the viewing conditions for many great observatories.

      Maybe that wouldn't be so bad. I say, the sooner we got astronomers off the surface and up to the far side of the moon, where they belong, the better.
  • Can transparent aluminium be far behind

    After all, most of us are reading this through a good chunk of transparent mixture of lead and sand! Yes, good quality glass used for CRT displays...

  • by Perdo (151843) on Monday January 28, 2002 @05:03AM (#2912723) Homepage Journal
    If you lived in a transparent concrete house would you still have to refrain from stone throwing?
  • by Ukab the Great (87152) on Monday January 28, 2002 @05:07AM (#2912730)
    First we had clear Pespi.
    Then we had clear deodorant.
    Saturday Night introduced us to clear gravvy.

    Like clear concrete was that far behind?
  • by Andy_R (114137) on Monday January 28, 2002 @05:15AM (#2912741) Homepage Journal
    Architect "...are the stairs, and this is where the wi..."
    Programmer "NO! NO! I will not have windows installed!"
  • ..the mafia will have to find other places to bury people like Jimmy Hoffa!
  • Glass (Score:3, Interesting)

    by Sprunkys (237361) on Monday January 28, 2002 @05:59AM (#2912813)
    and buildings whose windows need not be flat, rectangular panes, but can be arbitrary regions of transparency within flowing, curving walls.

    Sorry, but that is already possible.
    A researcher at the university of Delft has developed a way to create twisted glass allowing for twisted buildings.
    A dutch article can be found here [tudelft.nl]. Take a look at the images if you don't understand the text
  • by marcovje (205102) on Monday January 28, 2002 @07:34AM (#2912960)
    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.
  • Recycle (Score:2, Insightful)

    by ONOIML8 (23262)
    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.
  • by bdavenport (78697) <spam@sellthekids.com> on Monday January 28, 2002 @08:08AM (#2913028) Homepage
    this april 2001 edition of Metropolis [metropolismag.com] has a pretty informative article on the man and his background.

    interesting that i live in houston (concrete captial next to LA) and never have read an article on this guy.
  • Lens and the Sun (Score:4, Interesting)

    by Paul Johnson (33553) on Monday January 28, 2002 @08:15AM (#2913055) Homepage
    I can see a whole new collection of risks here, especially if there are any curved surfaces involved. At various times of the day a transparent product would focus the sun's rays into various hotspots. Some of these might be intense enough to cause burns or even fire. The lenses would not be terribly efficient, but they would be very large.

    Paul.

    • Good point. There are a great many hazards associated with transparent building materials and for some years now I've been campaigning to have them curtailed or even removed from building entirely. One such material is glass and the hazards are well known: risk of fracture, the ease of accident causation (eg. walking into glass doors) and, as you point out, risk of fire due to caustics produced by the curvature of glass. There are other more subtle risks such as the yearly loss of revenue due to espionage caused by the fact that just about every company has great big transparent regions in every room allowing spies to look in using binoculars (which themselves are testament the hazards of allowing the public free access to transparent materials).


      To add to these risks the hazards associated with translucent or transparent concrete is surely foolhardy. We already have far too much transparency in our society and it's time to bring this madness to a halt.

  • No, really!

    If high quality displays can be made inexpensively, of flexible material, and incorporate light sensors (presumably not overwhelmed with photons emanating from the display), would it not be possible to use them as wall paper on the inside and out and thereby achieve the illusion of transparency?

  • Just imagine what Steve Jobs would do with his iMac cases...
  • by NeuroManson (214835) on Monday January 28, 2002 @10:17AM (#2913511) Homepage
    I've calculated a possible material to use for the binding agent, that's a no brainer: Silicone (as it can be formulated for varying degrees of clarity and density)or fiberglas epoxy resins (the added bonus of this is fairly rapid curing...

    However, the ecological impact is a far better thing to consider... For example, recycled bottle glass can be ground down to make both aggregate and filler (you can seperate the colored glass and use that to add a touch of color to the finished product), and ground further down, it can act as filler as well...

    Considering that the majority of states in the US only have voluntary glass recycling, it might provide incentive for deposit glass bottles, not to mention finally provide a real incentive to recycle old CRT's...

    Or if you're feeling daring, you can use the same optical quality sand they use for reflective road striping to give the concrete an almost luminescent quality... For added strength, use polycarbonate rods or strips in a woven lattice...

    The article stated that transparent/translucent concrete can only be prepared offsite, but in theory it can be done the same way as existing concrete, just bring a lot of drums of resin or silicone to the site...
  • That's going to be the next headline. They'll design something like the Jacob Javits Center, and then we'll see transparent floors, and next thing you know, all the execs get sued for sexual harrasment because their secretaries all had offices on the floor above them, not next to them. And for some reason they had to wear skirts...go figure.
  • by Derek Pomery (2028) on Monday January 28, 2002 @11:59AM (#2914140)
    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.
  • by Restil (31903)
    Glass houses that are golf-ball resistant.

    And tornado resistant.

    Heck, even crowbar resistant. That's right Milo, keep whacking on that window, we'll get in eventually!

    -Restil

Klein bottle for rent -- inquire within.

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