[Ferro List] Fiberglass Ferrocement

[chuck east]

Hi Chris

Your comments remind me of just how chemical the 'real world' is and even if
I hope a given material is the ideal product (fiberglass in this instance) I
should know that there will be a reason that it can fail ... thus the ASR
will become a part of my thinking ... I am pleased that my attraction to
Metakaolin provides possible advantages in working with glass.  As for
laminating the glass with steel mesh my EMF concern has focused me on trying
to eliminate steel but perhaps there are steel mesh encapsulations that
create an electrical insulation of sorts ... I'll search for something along
those lines unless you know of some specific products that address directly
or indirectly this issue.

As for the 'proof being in the pudding' I'll look to a time when I can test
the sandwiched glass within steel ... some sort of mini-barrel that I can
subject to stresses adequately simulating Earth's pressures ... I can see
big learning curves approaching.

Following your very cool idea of constructing the LFC over shaped/molded
earth (then removing the earth) I still don't understand how I would
construct the foundation or if one is even required.  

I'm also noodling around the possibility of constructing the thin-shell
upside down in pieces thus avoiding the quixotic notion of flipping
something the size of the completed shell ... this will allow me finish the
inside of the shell to a high standard avoiding the challenges Michael
Angelo faced in the Sistine Chapel and then marry the pieces right-side up
... there would still be the finishing work as the final bits are laminated
together but this might be small potatoes compared to the entire shell ...
marrying the pieces would still require proper lamination thus I envisioned
leaving each piece with substantial mesh (and rebar if used) which would be
married to the adjoining pieces.  Amongst the great gaps in my knowledge is
whether or not I can actually marry the pieces without losing all the
qualities of strength and flexibility one wishes in LFC ... and I have not
idea if making the seams seamless will be difficult.

However I finally approach it, I'll work my way through some of the learning
curves by building (on site) one or two smaller modules - workshop/studio.

Cheers
Chuck  

-----Original Message-----
From: list-bounces at ferrocement.net [mailto:list-bounces at ferrocement.net] On
Behalf Of Christopher Glasspool
Sent: Thursday, January 24, 2008 4:06 PM
To: Ferrocement Discussion List
Subject: [Ferro List] Fiberglass Ferrocement

Hi Chuck,
You can purchase special glass mesh for stucco or ferrocement work, and it
is treated for the alkali environment to combat a problem called alkali
silica reaction (ASR), however it isn't a forever fix, and at some point the
glass may succumb to it's inability to stay inert in the mix.
The problem can be mitigated somewhat by keeping the ph of the mix down.
This is done with using a pozzolan aggregate, and by keeping moisture out.
This is accomplished by both having a quality mix, and keeping the water
ratio down. I believe Metakaolin is considered by some to be the better
pozzolan for glass lamination.
My thought on using glass mesh would be to make a lamination where the glass
was in the middle of the plane (the neutral zone), and have steel mesh on
the outside where the stresses are. Increasing the thickness without
increasing the steel should yield a great strength at reduced cost. This is
not a tried or proofed method though. - chris


 
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