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GSBN: Digest for 6/28/02



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-> Re: GSBN:More from Kelly about China
     by Paul Lacinski paul@...
-> Re: GSBN:more on fly ash, pozzolans
     by Paul Lacinski paul@...
-> Re: GSBN:more on fly ash, pozzolans
     by Bruce King ecobruce@...


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Date: 28 Jun 2002 17:39:41 -0500
From: Paul Lacinski paul@...
Subject: Re: GSBN:More from Kelly about China

Hello All,

One of the reasons the straw bale houses are succeeding in China is 
because they are so very similar to the brick houses.  Both are 
plastered inside and out.  The windows vary from location to location 
and house to house, but not according to whether the walls are of 
bales or bricks.  The heating systems are the same, a coal-burning 
steel firebox (leaky) hooked to a kang (raised platform with stove 
exhaust snaking through it) or firewall (brick wall with exhaust 
snaking through it) or both.  I do not recall any intake or exhaust 
dampers, but I'm not sure.  Ceiling insulation is usually bagged 
sawdust in both cases, and roofs and ceilings are the same.  Floors 
are slabs.  We're introducing the idea of coal slag as floor 
insulation, but it hasn't caught on yet.

The stoves do draw from the interior (as does the separate cooking 
stove), and so the fact that the bale houses use alot less coal 
points in the direction of Derek's conclusion as the major reason for 
moister interior air.  The other factor at work is that the brick 
walls are acting as de-facto dehumidifiers in the winter- their 
interior surfaces are apparently quite cold- so much so that frost is 
common in the corners of the buildings.  When people don't have this 
problem in the bale houses (thanks as much to the exterior insulation 
in the bond beams as to the bales) they are surprised and very happy.

Cheers,

Paul
- -- 
Paul Lacinski
Amy Klippenstein
GreenSpace Collaborative
Sidehill Farm
PO Box 107
463 Main St.
Ashfield, MA 01330 USA
01-413-628-3800


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Date: 28 Jun 2002 17:40:07 -0500
From: Paul Lacinski paul@...
Subject: Re: GSBN:more on fly ash, pozzolans

Bruce,

Thanks, this is very helpful.  So here's another bullet for your 
list- it seems as if fly ash + lime = cement.  This would mean that 
those of us in wettish climates who are concerned about maintaining 
maximum vapor permeability in lime plasters would be best off 
avoiding fly ash as a pozzolanic additive.  Yes?  And what about 
ground pottery or bricks (which I have used alot of) or hydraulic 
lime?  Do these have a similar effect on the lime?  My understanding 
is that they produce different compounds, entirely.

And you might be interested to hear that Amy (my wife) regularly 
refers to pozzolanic additives as pozzolanic adjectives, because she 
is finds them very exciting.  It has something to do with being 
allowed to build up such modified plasters as thickly as she might 
desire....

Thanks again,

Paul
- -- 
Paul Lacinski
Amy Klippenstein
GreenSpace Collaborative
Sidehill Farm
PO Box 107
463 Main St.
Ashfield, MA 01330 USA
01-413-628-3800


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Date: 28 Jun 2002 19:12:30 -0500
From: Bruce King ecobruce@...
Subject: Re: GSBN:more on fly ash, pozzolans

on 6/28/02 3:37 PM, Paul Lacinski at paul@...:

>  . . . So here's another bullet for your
> list- it seems as if fly ash + lime = cement.  This would mean that
> those of us in wettish climates who are concerned about maintaining
> maximum vapor permeability in lime plasters would be best off
> avoiding fly ash as a pozzolanic additive.  Yes?

Maybe si, maybe no.  A little bit of fly ash in a lime plaster will make it
more cementlike both in terms of (im)permeability, and added strength,
hardness, and durability.  I think you can well appreciate that this isn't
that simple, both because of the variations in lime & fly ash chemistry, and
in the site specific, even wall specific, demands of the project.  All in
all, I'd be inclined to add the ash - give up some permeability but gain a
lot of durability.


> And what about 
> ground pottery or bricks (which I have used alot of) or hydraulic
> lime?  Do these have a similar effect on the lime?  My understanding
> is that they produce different compounds, entirely.

Ah, yes, the old ground pottery or bricks trick.  thousands of years old,
still being practiced.  Fired clay is (generally) calcined clay which, when
finely ground, makes a fine pozzolanic adverb.  Of course, there are once
again many variations, but calcined clay is roughly equivalent to fly ash.

Bruce "Pozzolanic Attitude" King



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