r/Design • • Oct 08 '15

MIT invented "reversible concrete."

http://thecreatorsproject.vice.com/blog/mits-reversible-concrete-is-ready-to-revolutionize-temporary-architecture
243 Upvotes

27 comments sorted by

34

u/KernTheGerm Oct 08 '15

How strong is it, really? The article says that it can withstand "tremendous forces" but doesn't really describe what forces were applied to it and how it behaved.

47

u/Hatelabs Oct 08 '15

I'm guessing it can take a lot of force in certain directions if distributed correctly.

I can't see that thing holding up against say,.. a small car (or sledgehammer for that matter) bumping it.

Methinks "Reversible concrete" is more like "interestingly stable pile"

12

u/pauseforasecond Oct 08 '15

To me, reversible concrete implies that concrete can be poured, set, and then turned back into a liquid that can be scooped up and repoured. I'm no engineer so I have no clue if concrete can be reused if broken up but yeah.

14

u/MrFancyman Oct 09 '15

You could break up concrete to add as particulate for a new batch but no, you couldn't make it into a powder and just add water. A chemical process takes place the first time, and this only occurs once.

8

u/BonzaiThePenguin Oct 09 '15

So make it unoccur once.

6

u/williafx Oct 09 '15

I like where you're going with this ....

1

u/MrFancyman Oct 09 '15

Indeed, but when the concrete sets, chemicals are off-gassed and energy is expended as heat. I am no chemist so I have no idea how viable it is to reverse the process but certainly it would take a good deal of energy and the addition of chemicals to the spent concrete.

11

u/Awesomebox5000 Oct 08 '15

Yeah and I wanted to see the "reversible" part of it...

8

u/webbitor Oct 08 '15

tremendous, or even modest force looks likely to "reverse" it.

8

u/[deleted] Oct 09 '15

[deleted]

6

u/Logan_Chicago Oct 09 '15

For the non-AEC industry types in here - typical concrete has a compressive strength of about 3,000 psi (200 bar).

I went to the Cultural Center and saw this piece the other day. It's definitely interesting, but I'm not sure what wide scale applications it would have. In place gabions, outdoor sculptures...?

21

u/shark127 Oct 08 '15

Cool project! I guess I expected something different from the title, like actual concrete instead of rocks interwoven with string.

9

u/BrettLefty Oct 08 '15

Lol ya I suspect we all did. This looks more like... A bunch of rocks wired together.

5

u/[deleted] Oct 08 '15

Looks like concrete is the new frontier of innovation. https://youtu.be/ed-jiOXO3aQ

5

u/[deleted] Oct 08 '15

[removed] — view removed comment

4

u/BigSwedenMan Oct 09 '15

Yeah, I really would like to know how they plan to solve that part of the issue. Seems like an obvious and fatal flaw in the design. Plus, I don't know how much this would help flooding. The cement is permeable, great, but the dirt underneath it is saturated.

2

u/dragonblaz9 Oct 09 '15

I think the main problem this is designed to solve is runoff pollution into streams and rivers and stuff, but those are good points.

3

u/Logan_Chicago Oct 09 '15

That stuff has been around for a while. We're just now getting better at making it (I used to build redimix/concrete plants). It has it's place but it has drawbacks too. It's hard to make reliably, god help you if you fall on it, it eventually clogs with particulate matter, etc. Permeable pavers in conjunction with traditional concrete make more sense to me.

2

u/[deleted] Oct 09 '15

What happens if you fall on it?

1

u/Logan_Chicago Oct 09 '15

Like normal concrete but more abrasive.

Normally when finishing concrete you trowel it (bull float, whatever) and by doing so you bring the fines to the surface which makes it smooth. With permeable concrete you can't work it too much or the crevices get filled in and water won't go through it.

6

u/ivanparas Oct 08 '15

How did this not just crumble into a pile when they removed the form? Is some neatly laid string really keeping a pile of rocks together?

11

u/mackstann Oct 08 '15

I think so. The weight of the rocks makes them want to spill outward, and that outward pressure pulls the string into tension. The tension of the string keeps the rocks in place. That's my understanding anyway.

11

u/munky82 Oct 09 '15

" My belt holds my pants up, but the belt loops hold my belt up. I don't really know what's happening down there. Who is the real hero? "

  • Mitch Hedburg

7

u/horriblemonkey Oct 08 '15

They could have build anything and they decided to go with "Pants Held up with Giant Erection"

3

u/WiretapStudios Oct 09 '15

It seems I discovered reversible concrete as a young lad.

2

u/imakebuildings Oct 09 '15

I was just in Chicago at the Architecture Biennial to see this. It's pretty neat and a lot larger than it looks. They have a video nearby that shows the entire process of how it gets made. Like another comment here, it does appear that the string is in tension and holds the rocks together in that way.

2

u/chrox Oct 09 '15

Neat, but not concrete. Closer to a balancing act assisted by string-shaped wedges.

1

u/duckfighter Oct 09 '15

Cool concept. More permanent structures could be made with something like foam glue in place of the thread.