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GSBN: Digest for 10/3/02



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-> Re: test results
     by Bruce King ecobruce@...
-> Re: (Cement) Plaster Test Results
     by "Rob Tom" rw_tom@...
-> Re: EBNet Plaster Test Results
     by bruce king ecobruce@...


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Date: 3 Oct 2002 12:14:34 -0500
From: Bruce King ecobruce@...
Subject: Re: test results

on 10/2/02 8:28 AM, Athena & Bill Steen at absteen@...:

>  . . . could 
> it be that there were errors in the way the testing was carried out?

Nope;  we have one of the best labs around.  These guys know how to squish
stuff.

B



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Date: 3 Oct 2002 19:30:43 -0500
From: "Rob Tom" rw_tom@...
Subject: Re: (Cement) Plaster Test Results

ecobruce@... wrote:

>on 9/30/02 3:30 AM, Paul Lacinski at paul@...
>wrote:
>
> > Well yes, I find this just as perplexing as everyone else, since it
> > contradicts my experience just as directly as everyone else's.

>. . we're going to keep looking into it.

Your Highness;

I just went back to the EBN website and it appears that more info regarding 
the PC/lime test has been posted since I first had a look a week or so ago.

The new (to me anyway) info mentions that no moist curing measures were 
implemented and that it was during a hot spell when the samples were cured. 
The fact that there was no increase in strength over time and that there was 
actually a decrease in strength between 29 & 57 days seems consistent with 
what happens when too-rapid moisture loss is allowed to occur during the 
curing process (ie no further hydration of the cement, probably after the 
first couple of days resulting in a
$#!++y plaster).

Even though the results were disappointing (from the Portland cement 
producers point of view) the tests results were useful nonetheless in 
illustrating the importance of proper curing procedures. Oui ?

But that's not why I'm writing (just to pat y'all on the back, that is).

I did have a chance to look at the other material on the "testing " page and 
one item that was noticeable by its absence was a test which looks at the 
strength of the plaster-to-straw-to-plaster bond in a bale sandwich, for (1) 
bales on flat and (2) bales on edge.

Since the integrity of the bond plays a major role determining whether or 
not buckling of the skins will occur in a loadbearing situation, and hence 
the limits of the wall assembly's loadbearing capacity, it would seem that 
such a test would be at the forefront of an enginoid's mind.
Then again, who really knows what's in an enginoids mind ?

ie Does it really matter that the strength of the straw-plaster bond is 
practically non-existent with plastered bales-on-edge, for the magnitudes of 
the loads that are typical in residential SB construction ?

Another item which caught my attention was the M2 "Decay Properties" test. I 
think that it would be useful to determine what species of microbial 
critters reveal themselves and at which moistrure 
contents/temperatures/exposure times they do.

ie We know for a fact that straw is an ideal host to the deadly stachybotrys 
family of moulds, but as far as I'm aware, we don't know how far along in 
the decay process these moulds appear.

Perhaps the testing would reveal something along the lines of:

  14 days exposure @ 45% MC @ avg 70 degF... harmless mould
  21 days exposure @ 36% MC @ avg 65 degF... harmless fetid black goo
  2 months exposure @ 30% MC @average 70 degF ... stachybotrys atra

Perhaps Matt Summers has a girlfriend in the Faculty of Microbiology who 
could do the mould identification for y'all, just for the sheer fun of it ?

The utility of such test data might be that people with wetted walls could 
possibly avoid potentially health-endangering situations by knowing when not 
to poke their heads into rotted SB walls.


  --- * ---
Robert W. Tom
Kanata, Ontario, Canada
rw_tom@...

please visit:  http://www.theHungerSite.com daily




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Date: 3 Oct 2002 20:46:36 -0500
From: bruce king ecobruce@...
Subject: Re: EBNet Plaster Test Results




Rob   "Just call me the James Brown of straw bale"  Tom wrote:

>  . . .  though the results were disappointing (from the Portland cement
> producers point of view) the tests results were useful nonetheless in
> illustrating the importance of proper curing procedures. Oui ?

Mais oui!


>  . . one item that was noticeable by its absence was a test which looks at
the
> strength of the plaster-to-straw-to-plaster bond in a bale sandwich, for (1)
> bales on flat and (2) bales on edge . . .

Many hours were spent designing such tests, and then, agonizingly,
eliminating them with the budget pinch.  We decided that we would learn
inferentially about those properties in the other tests we will do.  It
ain't perfect, but that's what we could afford.


>  . . . Another item which caught my attention was the M2
> "Decay Properties" test. I think that it would be useful to determine what
>  species of microbial critters reveal themselves and at which moistrure
> contents/temperatures/exposure times they do.

Yes, and with your donation of a few grand (Murrican dollars, Rob) we could
do that.  The test as is measures decay by 1) visual observation, and 2)
measuring the production of CO2 gas (apparently a clear indicator of
microbes partying wildly in the straw).

I'll ask Matt Summers if we can identify the spores - he may know offhand -
but even then they won't necessarily be the same bugs that Canadian
moosehuggers or Lars Keller or Barbara Jones or Wolfman down under or even
Matts "ain't no bugs on me" Myhrman would get in Tucson.

Final note:  I nominate Tim Owen-Kennedy and John Swearingen to this list
(though maybe John is already lurking on the list, I don't remember).  They
are two of the premier bale builders in California, have contributed
enormously to our knowledge and fun, and, well, just ought to be on this
list.

Do I hear an "Aye"?

Bruce King, PE
Structural Engineering Design
and Director,
Ecological Building Network (EBNet)
209 Caledonia Street
Sausalito, California    94965   USA
www.ecobuildnetwork.org

(415) 331-7630
fax (415) 332-4072
ecobruce@...



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