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GSBN:Re: (Cement) Plaster Test Results
on 9/30/02 3:30 AM, Paul Lacinski at paul@...
> 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.
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
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
please visit: http://www.theHungerSite.com daily
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