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Using a novel polymerization process, MIT chemical engineers have created a new material that is stronger than steel and as light as plastic, and can be easily manufactured in large quantities.
The new material is a two-dimensional polymer that self-assembles into sheets, unlike all other polymers, which form one-dimensional, spaghetti-like chains. Until now, scientists had believed it was impossible to induce polymers to form 2D sheets.
Such a material could be used as a lightweight, durable coating for car parts or cell phones, or as a building material for bridges or other structures, says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the senior author of the new study.
[...] The researchers found that the new material's elastic modulus — a measure of how much force it takes to deform a material — is between four and six times greater than that of bulletproof glass. They also found that its yield strength, or how much force it takes to break the material, is twice that of steel, even though the material has only about one-sixth the density of steel.
Irreversible synthesis of an ultrastrong two-dimensional polymeric material (DOI: 10.1038/s41586-021-04296-3) (DX)
From the paper:
Further processing yields highly oriented, free-standing films that have a 2D elastic modulus and yield strength of 12.7 ± 3.8 gigapascals and 488 ± 57 megapascals, respectively.
(Score: 2) by JoeMerchant on Monday February 07 2022, @03:16PM (11 children)
They already started coating the rebar itself decades ago (in better reinforced concrete construction techniques), this might make a stronger / thinner coating, but I doubt it will be cheaper any time soon.
Coating the outside of the concrete would be a tricky business - what's the UV exposure resistance of this stuff like? If the concrete is "mostly" coated but gets cracks that let water in, but not let it "breathe" like uncoated concrete - that will be different....
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 2) by Runaway1956 on Monday February 07 2022, @03:44PM (10 children)
Yeah, I've used vinyl coated rebar, personally. A study revealed that it's not the cat's meow, it sill corrodes, albeit, a little slower than naked rebar. Galvanized rebar lasts much longer, but it is also much more expensive. In both cases, bending, shaping, and dragging the rebar around during assembly causes damage to the coating, shortening the life expectancy. I suppose the ideal situation would be to bend and shape the rebar before coating, but that's very impractical, and you would still have some damage from handling and assembly.
And, answering part of my own implied question above: we would probably see those same problems if the rebar were coated with this new polymer. Maybe if the polymer could be applied after the rebar was assembled, those problems would be eliminated? Alternatively, the rebar were coated at the factory, then an additional fix-it layer could be applied on site, after the rebar was assembled into it's final form.
And, none of that addresses expense. Already, very few projects use galvanized rebar because of the expense.
Abortion is the number one killed of children in the United States.
(Score: 2) by JoeMerchant on Monday February 07 2022, @03:50PM (7 children)
There is some possibility for "field repair" of galvanized coatings with cold-spray zinc, I did this on my galvanized pipes and - it's not 100%, but it is 95% better than just letting the threads and wrench marks rust. Also, just having an abundance of zinc trapped in the concrete near the rebar is going to be a good thing in terms of which gets oxidized first.
For me, it's a question of project expected lifetime. If you expect this concrete to last 200 years, then of course you should do everything possible to prevent spalling, etc. If this is more of a 20 year thing that is likely to be demolished before ordinary rebar fails... yeah, ordinary rebar it is.
Then we get to the deeper motives of the construction industry, which often lean toward the "us and our kids are going to be out of work if this thing lasts forever" side.
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 1) by khallow on Monday February 07 2022, @04:21PM (6 children)
(Score: 1) by khallow on Monday February 07 2022, @05:24PM (3 children)
(Score: 2) by JoeMerchant on Tuesday February 08 2022, @01:20AM (2 children)
Whoever named fiber bundles "Basalt" needs to be flogged with a cat-o-nine Thesauri, knocked over the head with a stone slab, and then have their permission to write where others can read suspended until they can show better judgement. Permission to name things revoked until their next incarnation.
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 1) by khallow on Tuesday February 08 2022, @02:12AM (1 child)
Well, there seems to be something [smarter-building-systems.com] to that:
(Score: 2) by JoeMerchant on Tuesday February 08 2022, @03:49AM
Then you call the material "Basalt fiber." One does not call Carbon Fiber "charcoal", nor does one call Glass Fiber "beach sand."
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 2) by JoeMerchant on Monday February 07 2022, @06:42PM
Stainless would be roughly double: https://smallbusiness.chron.com/price-galvanized-steel-vs-stainless-steel-15433.html [chron.com]
lots of variables, how thick is your galvanizing, what alloy is your stainless, etc. Stainless also isn't as desirable from a ductility standpoint as regular iron / galvanized - probably needs to be a bit thicker for equivalent applications, raising the price further.
If you can manipulate basalt into structural rods, you don't need concrete.
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 1) by chair on Tuesday February 08 2022, @12:11AM
The cost of the two most common grades of stainless steel rebar (at least in North America) are ~10x that of regular un-coated steel, whereas galvanized is ~2x, and epoxy coated ~1.5x. [x]FRP's seem to be ~2.5x, although there are many types that can get more expensive. Sometimes cheaper, lower grades of stainless are used (e.g. MMFX), but I've seen them start to rust on site before installation.
(Score: 1, Informative) by Anonymous Coward on Monday February 07 2022, @07:52PM (1 child)
This page https://www.homeadvisor.com/cost/outdoor-living/steel-reinforcement-bars-pricing/ [homeadvisor.com] shows:
Galvanized rebar +10% - 15% over untreated steel
The galvanization process provides an exterior coating of zinc to combat long term corrosion.
Compares some other coatings too. About half way down the boring page...
(Score: 2) by Runaway1956 on Monday February 07 2022, @10:19PM
+1 informative - but I'm out of moderator points.
Abortion is the number one killed of children in the United States.