[PSUBS-MAILIST] concrete

Mon Apr 14 09:27:42 EDT 2014

Fascinating. I think that counts as water pollution in Europe...

Marc

On 4/14/2014 6:52 PM, Joe Perkel wrote:
> Marc,
>
> Strictly from my foggy memory, but I believe it was scuttled.
>
> Joe
>
> Sent from Yahoo Mail for iPad <http://overview.mail.yahoo.com?.src=iOS>
>
>
> ------------------------------------------------------------------------
> *From: * Marc de Piolenc <piolenc at archivale.com>;
> *To: * <personal_submersibles at psubs.org>;
> *Subject: * Re: [PSUBS-MAILIST] concrete
> *Sent: * Mon, Apr 14, 2014 3:30:48 AM
>
> Really - it sank? Mind you, it did have walls 6 inches thick and very
> little freeboard. Any lives lost?
>
> Marc
>
> On 4/13/2014 10:35 PM, Joe Perkel wrote:
>  > It seems to me that with reduced cost materials there is a tendency to
>  > go big and unwieldy.
>  > Wasn't that the case with that one fellows concrete sub yacht? It's on
>  > the bottom of a lake somewhere if I recall.
>  >
>  >
>  > Joe
>  >
>  > Sent from Yahoo Mail for iPad <http://overview.mail.yahoo.com?.src=iOS>
>
>  >
>  >
>  > ------------------------------------------------------------------------
>  > *From: * Sean T. Stevenson <cast55 at telus.net <javascript:return>>;
>  > *To: * Personal Submersibles General Discussion
>  > <personal_submersibles at psubs.org <javascript:return>>;
>  > *Subject: * Re: [PSUBS-MAILIST] concrete
>  > *Sent: * Sun, Apr 13, 2014 6:16:35 AM
>  >
>  > I ran that same 6' diameter 4" shell, but using an ultra high-performace
>  > concrete with no aggregate, but with steel fiber reinforcement.  Working
>  > pressure came out to more than 1700 m.  That said, while the compressive
>  > strength of this stuff is 160 MPa, the tensile is only 8 MPa, so you
>  > absolutely have to avoid putting this stuff in tension.  Sphere may not
>  > be an issue, but a cylindrical hull would probably require some sort of
>  > pretensioned reinforcement.  Results:
>  >
>  >
>  >
>  >
>  > On 2014-04-12 21:52, Marc de Piolenc wrote:
>  >> I had forgotten about the lubricant/plasticizer properties of fly ash.
>  >>
>  >> Marc
>  >>
>  >> On 4/13/2014 10:55 AM, hank pronk wrote:
>  >>> Marc,
>  >>> We don't get segregation at all, when pumping it we fill the wall and
>  >>> then let it flow, I call it "ride the wave"
>  >>> Also pumping the concrete helps hold the concrete together, it stays
>  >>> in a cylinder shape until it hits the wave. We must use fly ash
>  >>> because the aggregate and sand is washed so well there are no fines
>  >>> left.  The jagged sand won't flow through the hose.  Fly ash is like
>  >>> little ball bearings and makes it flow through the hose.  These are
>  >>> the things that make me think a mold  is the way to go.  Four inches
>  >>> wall thickness would be a breeze for this mix.
>  >>> That makes sense that the rock is a cheap filler.  I would still use
>  >>> the pea gravel mix, I have made a test panel and I drove my bob-cat
>  >>> over a 2in thick 4by4 panel with no breakage.  I know, very
>  >>> scientific .lol
>  >>>
>  >>> Hank
>  >>> --------------------------------------------
>  >>> On Sat, 4/12/14, Marc de Piolenc <piolenc at archivale.com
> <javascript:return>> wrote:
>  >>>
>  >>>  Subject: Re: [PSUBS-MAILIST] concrete
>  >>>  To: personal_submersibles at psubs.org <javascript:return>
>  >>>  Received: Saturday, April 12, 2014, 10:40 PM
>  >>>
>  >>>  Actually, all else being equal, using
>  >>>  only fine aggregate (sand) will give a stronger mix. Coarse
>  >>>  aggregate is needed mainly to make the mix affordable - as
>  >>>  bulk filler, in other words - and also for decorative effect
>  >>>  in some applications where the fresh concrete is brushed to
>  >>>  show off the aggregate.
>  >>>
>  >>>  You have to be careful, in very high-strength applications,
>  >>>  to make sure that the coarse aggregate is chemically inert
>  >>>  with respect to the cement matrix. Some siliceous aggregate
>  >>>  will weaken the concrete in the long term by reacting slowly
>  >>>  with the matrix long after cure.
>  >>>
>  >>>  Confusingly, very fine silica incorporated in the form of
>  >>>  fly ash, rice husk ash or silica fume can give a
>  >>>  super-HIGH-strength mix. The reason for the effect is that
>  >>>  the very fine silica reacts with the alkali formed DURING
>  >>>  cure and actually strengthens the cement matrix.
>  >>>  Unfortunately, much of the fly-ash and volcanic ash cement
>  >>>  on the market is too coarsely ground to harness this
>  >>>  effect.
>  >>>
>  >>>  Best,
>  >>>  Marc de Piolenc
>  >>>  Ferrocement freak
>
>  >
>  >
>  >
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>
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