
Spheres can make concrete leaner, greener - dnetesn
https://phys.org/news/2018-09-spheres-concrete-leaner-greener.html
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todd8
I would feel a lot more comfortable with these spheres being used in
construction if they were 1000 larger in diameter. The size cited is 50nm to
100nm, roughly the same size as another non-reactive compound that is believed
to have real risks associated with it, titanium-dioxide. See
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3873219/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3873219/)

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everyone
I hope they dont cause any weird diseases.. I'm just thinking of asbestos-
concrete.. It was amazing at the time, far greater tensile strength _and_ fire
safety.

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jghn
And also completely not dangerous, yet it received the banhammer

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devwastaken
In what manner is the risk eliminated?

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jghn
Because of the cement the asbestos is not friable and thus doesn't pose a
mesothelioma risk. Sure, it'd not be great to do lines of ground up asbestos
fiber cement, but that has a lot more to do with it not being a good idea to
do lines of cement in general and nothing about the asbestos side.

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nate_meurer
This comment is so naive and ignorant, it hurts. I'm sorry to be so harsh,
really, but I hear this bullshit depressingly often, and ignorance like this
has really contributed to an epidemic of asbestos contamination that is still
very much with us.

Cement is a temporary matrix. Concrete and other cementitious structures are
constantly weathering, degrading, and being demolished all around us. Right in
my own back yard a 30-year old concrete patio is spalling, the flakes slowly
turning to fine dust with every foot fall. Dust which is then blown about my
yard and tracked into my house. Do you imagine that dust would remain
"completely not dangerous" if it contained asbestos?

And apparently you've never worked with concrete or grout, because otherwise
you'd have witnessed the unavoidable clouds of cement dust that erupt any time
you open a bag, pour, shovel, or even breathe on dry mix.

> _it 'd not be great to do lines of ground up asbestos fiber cement, but that
> has a lot more to do with it not being a good idea to do lines of cement in
> general and nothing about the asbestos side._

Any asbestos in ground-up fiber-bearing cement would be, _by definition_ ,
friable. That's what the word means.

Long time ago I'd hear people say the same thing about asbestos cement siding
-- as though the cement will encase the asbestos for all eternity. As though
no one ever re-sides their house, or as if re-siding never involves breaking
or disturbing the old siding. The abject stupidity of such assumptions is
immediately apparent the moment you break a piece of siding, either during
installaion or removal, and you see a puff of asbestos and cement dust spring
into the air.

Again, I'm sorry for speaking harshly, but asbestos kills, and people like you
who spread the "asbestos is safe when properly applied" bullshit have made it
that much harder for us to get rid of the stuff.

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cwkoss
Aircrete is similar and very interesting: mix fine dishsoap bubbles into
concrete and you can actually reduce density so much that it will float on
water!

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Fjolsvith
Concrete boats.

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cwkoss
The US military actually used concrete 'blockships' to create an artificial
harbor for use in D-day. Doesn't need to be aircrete to float if correct
shape!

[https://warfarehistorynetwork.com/daily/d-days-concrete-
flee...](https://warfarehistorynetwork.com/daily/d-days-concrete-fleet/)

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soperj
>micron-sized calcium silicate spheres

Wonder what these will do when the concrete eventually degrades. How do these
spheres act in the environment? what happens when they end up in the water
system and are ingested by animals (including humans)?

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UpshotKnothole
Micron sized should be fine, and they’re going to form a. God phase when
hydrated so you don’t have to worry about long-term friability. Nanoscale
would be a concern because of the ability to directly enter cells, but micron
would be fine unless you’re breathing a cloud of the stuff when it’s fresh ad
dry. Under normal wear and tear that won’t happen.

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jwilk
"a. God"?

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UpshotKnothole
My fat fingers and iPad’s autocorrect is a bad combo. Should read: Gel phase.

God phase would be... nifty?

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sbradford26
After a bit of research it looks like it would be replacing Portland cement
which is made with limestone, clay, and gypsum. Which makes me wonder how cost
competitive this will be, since those materials are very cheap.

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bluGill
You forgot about energy in your list of ingredients. Portland cement needs a
lot of energy to make. The materials you list are the cheap ones, energy is
the expensive one.

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cryptonector
Perhaps this could end beach and river bed theft?

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politician
Can you elaborate? Is concrete regularly stolen from beaches?

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mabbo
Sand is stolen in large quantities in many countries to be used in concrete
production.

Example:
[https://en.m.wikipedia.org/wiki/Sand_mining_in_Tamil_Nadu](https://en.m.wikipedia.org/wiki/Sand_mining_in_Tamil_Nadu)

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here2day
How quickly can this be replicated? Huge business potential.

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quirkot
Based on my previous experiences with disillusionment, here's my rule of
thumb:

Late stage research announcement to viable product/start-up announcement: 1-2
years

Start-up to commercially useful: 2-3 years

Commercial viability to industry impact: 3-5 years

Can go quicker and if research is preliminary can go much longer. But this is
what I tell myself when I see something I'm excited about

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nashashmi
Good reminder! Also to mention: When researchers research about some new
Magical thing, they need to also come up with potential applications to
continue receiving funding, prospective interests, get publicity, etc.

It is very possible that this article could be nothing more than: Researchers
unveil new nano-material with high strength properties, cite concrete as a
possible application supplement.

