Concrete Casts New Light in Dull Rooms

opticsorg writes "Stuck for decorating ideas? Then the light-transmitting concrete that is set to hit the market this year is what you could be looking for! The days of dull, grey concrete could be about to end. A Hungarian architect has combined the world's most popular building material with optical fiber from Schott to create a new type of concrete that transmits light. A wall made of 'LitraCon' allegedly has the strength of traditional concrete but thanks to an embedded array of glass fibers can display a view of the outside world, such as the silhouette of a tree, for example."

Comments

Re:And the reverse?

[p4ul13]

You're right. It is almost certain that the outside world should be able to see your "shadow puppet" at night.

As for the color of the wall, there was a picture on the site that showed a brown wall, so I guess the stuff could be dyed when it is manufactured, but I think repainting your room would be out of the question..

Translucent Concrete

[shaka999]

While this is a cool idea its not that original

http://www.economist.com/science/tq/displayStory .c fm?Story_id=779421

Bill Price's version actually sounds like it lets through more light but is also harder to work with.

Re:Translucent Concrete

[jc42]

It's a much, much older idea.

Before the 20th century made artificial lighting cheap, it was common for the holds of ships to be illuminated by light coming in through a lot of thick lenses that were embedded into the deck. The lenses were usually roughly pyramidal in shape, with the point down of course. Holes would be drilled in the deck, and then shaped so that the lenses would fit into them flush with the deck. You can see a lot of these in maritime museums these days, as well as in the decks of some of the historical ships in a few harbors.

Of course, they didn't transmit any sort of image. But you wouldn't want them to, really. They just has to be translucent and tough enough to take all the beating they got from above.

Of course, people also included glass bricks in walls for the same purpose. They're still for sale.

Re:Cool!

[Bazzargh]

From the pictures on the site, I imagine that they are just going to make a full piece of cement to your size specifications insted of you buying a whole bunch of smaller blocks and cementing them.

No, this picture clearly shows bricks. However generally cement isn't going to be a problem for this material. You can see that he's running fibres from one site of the concrete to the other. The light you see on one side appears in the position it fell on the other side, (look at the two shadows of the woman's right arm - the one cast outside the block is lower than the one cast through the block).

This being the case,you can create room for a channel of cement between blocks by bending the fibres, while having the blocks appear to be flush on the outside. ie:

|upper______block|
|/////CEMENT\/<--- fibre bends round channel
|___/________\___|
|lower//////block|
| ////////////////|

Re:Unanswered question

[Anonymous Coward]

for a first-order approximation (assuming isotropy), try the old Rule of Mixtures:

k=(ki*xi)+(kj*xj)+...(kn*xn)

where:
i, j, ...n are the components,
k is the property (in this case, thermal conductivity)
and
x is the fraction of the different components.

assuming:
k(e-glass) ~1.0 W/mK
k(concrete)~1.28 W/mK
k(air) ~0.025 W/mK

if the concrete block is 45% glass, 55% concrete, it has a thermal conductivity of (isotropic assumption) ~1.154 W/mK
assuming that the glass brick is hollow, and ~50% solid glass, it has a thermal conductivity of ~0.5125 W/mK.