Topic awaiting preservation: Light transmitting concrete? (Page 1 of 1)

They say people in glass houses shouldn't throw stones..

hm... I just glanced over it, it look cool. Is it one way, though?

Yeah, it looks really cool, but I had the same question as TP.

Dunno if I want see through walls in both directions, even if it is just a silhouette.

I just hovered the article, but it seems to transmit the light only in one direction. ( cf the image of the hand on concrete viewed from the two angles on their site ).

I wonder how much more expensive it is compared to normal concrete. Nonetheless I already see the huge beneficit for the architects. Imagine some public libraries, museums, ... or what could be done if we mix normal and light transmitting concrete to do some patterns of light on the buildings or ceilings. If they do several type of "bricks" with different density of glasses we could even play with the difference of intensity. ATM I think to the François Mitterand nationnal library, it would rock to see his face on the outer walls due to the light transmitted from the library itself. That's just an example, but it could be applied to stadiums ( think to the Olympic stadiums ), concert halls, malls ...

I also wonder how it behaves with colored light.



[This message has been edited by poi (edited 03-19-2004).]

Very interesting! It's amazing, the things they can do with building materials these days. I'm with Poi on this - can't wait to see some museums and libraries made of this stuff... not to mention office buildings! Think of the difference it would make in people who are confined to closed internal spaces... Sunlight is important for staving off depression - being able to transmit even a portion of natural light into an enclosed building would make huge differences in people's moods.

The one-way effect is kind of cool - you could see the shadows of trees and things outside, but no one could see you! Good deal - there's not a lot that goes on in my house that I want the outside world taking notice of...
heh heh...

I think there was an extensive article about this stuff in Scientific American in the late 1980s or early 1990s. They were describing the fractal nature of the fibers used to make the "concrete". at that time it was thought this might be used as a replacement for glass in house in the far north. The material is translucent, rather than transparent.

Because of the fractal nature of the material, it is very light, a good insulator, and also transmits light.




-- not necessarily stoned... just beautiful.

Imagine these in theaters, with some colored spots behind them. Wow what i could do with that, putting the light in the wall instead of on the wall. As light and sound engineer i am thrilled buy this...

~wanders off looking for a couple PAR65 stage spots to play with~

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Doe something usefull: support Justice for Pat Richard

In fact, I even thought to offices obviously but also to hospitals and even jails.

Very cool. I like the idea of putting lights in the walls.

However, on the issue of it being one-way, I don't see anything indicating this. I believe it's simply a translucent material.

I think the source of the confusion is this quote: "Shadows on the lighter side will appear with sharp outlines on the darker one." I believe this is just in reference to the environments on either side of the wall. The side with light (outside, during the day) will show on the darker side (inside, where it's darker). It only makes sense -- like with a sheer curtain, you can see through from the darker side to the lighter side, but not very well the other way round.

At night, with lights on inside, the building would glow. You wouldn't be able to see any real detail, just figures and some color.

quote:

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At night, with lights on inside, the building would glow

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I could use two walls (very common, for isolation purposes, in the netherlands) an outer brick wall and an inner "LitraCon" wall with some lights put between both walls. Then the inner wall wil glow and the light will be put in the wall. You could even color the wall if you could change the color from the lights.

Wes think about the things you could do in a tv-studio put up a wall, let your VIP/mysteryguest/presentator enter from behind the wall. Put some lights behind it for cool effects and you have very interesting entrance to the show.

Also if someone is going to make another Big-Brother series, make the outside walls from the home with this material....

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Doe something usefull: support Justice for Pat Richard

It's nothing surprising for me glass is made of silice an amorphe compounds more or less near the concrete composition.

You have concrete with density less than the water too, university student like me know that Because of the concrete canoe race!

Why do you feel concern by that?

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Don't click here

Someone correct me if I'm wrong, but I don't believe the concrete has a lower density than water -- the canoes float due to displacement. Same as a steel ship -- the steel doesn't have a lower density than water.

But back to the wall -- you could also project simple images onto the back of the wall for some neat effects.

Or light each block individually, like pixels. Used on the outside, you could change the look of your home(office building...) by projecting a new "image".
Just don`t let the marketing dept. play with it.

quote:

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Someone correct me if I'm wrong

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You can build:

1. Light concrete with a density less that the water one.

It's all about displacement however floating concrete is possible.

look at this picture you will understand it's no all about displacement

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Don't click here

First up: Big contradiction here

quote:

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It's all about displacement however floating concrete is possible.

look at this picture you will understand it's not all about displacement

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See?

But, Zigot, in your page of pictures, I can tell you what is happening. The canoe is not made out of a less dense concrete. Shotcrete is a very liquid concrete, nice and thin so it can be sprayed onto a surface. The concrete isn't less dense than normal, simply more liquid before it goes off. The canoe itself is simply very light (and tough) fibreglass layers sandwiched with (heavy, and weak becuase of a lack of reinforcement) concrete. So, it is all about the displacement. If you made the canoe entirely out of concrete it would be so heavy that its weight would be higher tha nthe amount of water it could displace, and so it would slowly sink.

Justice 4 Pat Richard

When i learned about wooden boatbuilding i learned about the displacement stuff...

Density?
Try floating a solid concrete cube which has sides from about 1meter. If you could do this then it's density is lower than water. This will only happen when your cube of concrete is in a very deep ocean trog say about 1000m, due to the water pressure above the concrete cube could have a lower density than the water beneath it and hover.
Now try this with a solid wooden cube from the same size, depending on the wood used it will float or hover close to the water surface.

Displacement?
The showed cannoe has definetly an boat-shape so it wil push the water aside, displacing it. The displacing would not work when the cannoe was filled with water. The boat would get the same weight as the surrounding water plus the weight of the boat itself thus it would sink. However since it's actually filled with nothing but air it will float.
It contains something lighter than the surrounding surface. Put some weight in it (you on a nice summer day) and the canoe will be lower in the water. Thus Displacing more water.
The importand things are surface of the floating object compared to its weight and shape. You could float everything with a big enough surface and a shape which 'pushes' the water aside.


btw sorry for spelling mistakes and so on, my brain did some overtime to try translating this theory to normal english.

class dismissed.

ZB the link you put in seems interesting to look at (when you like boatbuilding that is).

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[This message has been edited by Rinswind 2th (edited 03-22-2004).]

>Stands behind Skaarjj and Rinswind, sticking his tongue out.<

Actually guys, speaking as a Physicist, its ALL about displacement.

The block of wood floats because the volume of water it displaces has more mass than the wood. The block of concrete you described Rindwind sinks until the density of the water becomes great enough that the concete is displacing a greater mass of water than its own. The canoe or a steel ship or a wooden ship float because they displace a volume of water that has a greater mass than they have.

Try putting a hole in the side of a ship (concrete, steel, or wood). It will sink because the ship is no longer displacing a mass of water greater than its own mass.

It is ALL about displacement.



-- not necessarily stoned... just beautiful.

err....

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Do something usefull: support Justice for Pat Richard

check these out.. http://www.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/images/mirror.mpg http://www.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/images/oc-s.mpg http://www.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/images/oc-okugai3.mpg http://www.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/images/bone2.mpg

Guess what ... I can do the same thing in the studio at work. (It's called chromakey.)

I will be impressed when it comes in bags at the local hardware store, and i get to mix it myself.


[antique sigs are us]

heh i'm just imagining making a biiig statue out of this stuff out in the country somwehere, and then at night when someone came past making it all glow from the inside. Hehe how bout a glowing 100ft statue of me, that'd be pretty awesome.

sets off to build....

~Sig coming soon~

Happy I could provide a reference to some stimulating conversation.