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GSBN: Digest for 7/5/07



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-> Re: GSBN:Re: Werner Schmidt
     by billc billc_lists@...
-> Re: GSBN:Cemento (combined responses)
     by jfstraube@...
-> Re: GSBN:Cemento (combined responses)
     by Derek Roff derek@...
-> Re: GSBN:Cemento (combined responses)
     by Mark Piepkorn mark@...


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Date: 5 Jul 2007 01:09:19 -0500
From: billc billc_lists@...
Subject: Re: GSBN:Re: Werner Schmidt

Werner has been on the list for a fair while.

He's just quiet.


- --
Bill Christensen
billc@...

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Date: 5 Jul 2007 07:33:48 -0500
From: jfstraube@...
Subject: Re: GSBN:Cemento (combined responses)

I also think one has to consider that cement is just one material that is
used. It is used an awful lot, and this is part of its environmental
footprint. However, the reason it is used a lot is that it is made of clay and
limestone (available most places in quantity) and results in a very durable
and low dollar cost product. 
I am all for reducing cement use, and changing cement manafucturing to
dramatically reduce CO2 and other emissions. however, if the replacement for
the apartment buildings in China is, for example, steel, then the CO2
emissions will rise dramatically as steel will use more energy and CO2 for the
same beam or column. 
Lots of cement is used in heavy civil works like roads, and sewers, curbs and
sidewalks. There are some replacements, but few work as well.
At the end of the day, I think cement is one of many materials that we need to
use more wisely and hence less of, but for many purposes, it is hard to find
an equally durable, non-combustible material that has less impact.
One of the clear substitutions is wood framed housing instead of concrete.
This works in some places, like where they have trees, but there are limits to
height, fire resistance, and durability that are quite practical. For most
other applications, like basements,bridges, sewer pipes etc, I think we can
gain more by be smarter in its use (optimally designed structures) and
dramatically improve is production (e.g. there is little reason why a
coal-fired cement plant could not use carbon sequestration.

Graeme North wrote:
> Thanks Mark - 
> 
> It looks as though the 6-10% figure so often quoted in green architecture
> circles for cement manufacturing1s CO2 contribution may be partially right-
> and wrong.
> 
> But see a graph at 
> 
> <a  target="_blank" href="http://cdiac.esd.ornl.gov/trends/emis/glo.htm";>http://cdiac.esd.ornl.gov/trends/emis/glo.htm</a>
> 
> This was in one of the references Mark so kindly put out.  It puts cement
> manufacturing contribution at somewhere around  2-3 %  annual global CO2
> emissions 
> 
> So although cement is one of the major players in the world1s pollution, and
> certainly in the construction industry1s contribution, it looks to me that
> although its present contribution may now be nearer 2-3 % of overall annual
> global CO2 emissions, its cumulative total effect of all human generated CO2
> appears to be nearer 8% -  does this look right to anybody else?
> 
> 
> Graeme,
> Graeme North Architects,
> 49 Matthew Road,
> RD1, Warkworth,
> New Zealand 0981
> Ph/fax +64 (0)9  4259305
> 
> www.ecodesign.co.nz
> 
> 
> 
> 
> 
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email to GSBN@...HELP in the SUBJECT line.
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> 
> 
> 
> 
> 
> 

- -- 
Dr John Straube, P.Eng.
Associate Professor
Dept of Civil Engineering &amp; School of Architecture
University of Waterloo
Waterloo, ON Canada




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Date: 5 Jul 2007 10:13:11 -0500
From: Derek Roff derek@...
Subject: Re: GSBN:Cemento (combined responses)

What are some examples of using less Portland cement to do the same
job?  Adding fly ash has been mentioned.  Rob Tom advocated the
development of an inside out insulated concrete form, where the
concrete skins would be on the outside, and the foam in the middle.
Rene and maybe Lars talked about using a small amount of cement, to
cement seashells together, with lots of air gaps.  Living near
volcanoes, pumice-crete uses the same idea, with a little cement and a
lot of pumice.  A cement grade beam on a rubble trench saves a lot of
concrete, with potentially superior performance.  Each of these
approaches can save many tons of cement, while using local, low
embodied energy materials such as seashells, rock or pumice.

Other examples and techniques?

Derek

- --On Wednesday, July 4, 2007 9:39 PM -0400 John Straube
jfstraub@... wrote:

> I also think one has to consider that cement is just one material
> that is used. It is used an awful lot, and this is part of its
> environmental footprint. However, the reason it is used a lot is that
> it is made of clay and limestone (available most places in quantity)
> and results in a very durable and low dollar cost product. I am all
> for reducing cement use, and changing cement manafucturing to
> dramatically reduce CO2 and other emissions. however, if the
> replacement for the apartment buildings in China is, for example,
> steel, then the CO2 emissions will rise dramatically as steel will
> use more energy and CO2 for the same beam or column. Lots of cement
> is used in heavy civil works like roads, and sewers, curbs and
> sidewalks. There are some replacements, but few work as well.
> At the end of the day, I think cement is one of many materials that
> we need to use more wisely and hence less of, but for many purposes,
> it is hard to find an equally durable, non-combustible material that
> has less impact.
> One of the clear substitutions is wood framed housing instead of
> concrete. This works in some places, like where they have trees, but
> there are limits to height, fire resistance, and durability that are
> quite practical. For most other applications, like basements,bridges,
> sewer pipes etc, I think we can gain more by be smarter in its use
> (optimally designed structures) and dramatically improve is
> production (e.g. there is little reason why a coal-fired cement plant
> could not use carbon sequestration.
>
> Graeme North wrote:
>> Thanks Mark ?
>>
>> It looks as though the 6-10% figure so often quoted in green
>> architecture circles for cement manufacturing?s CO2 contribution may
>> be partially right- and wrong.
>>
>> But see a graph at
>>
>> <a  target="_blank" href="http://cdiac.esd.ornl.gov/trends/emis/glo.htm";>http://cdiac.esd.ornl.gov/trends/emis/glo.htm</a>
>>
>> This was in one of the references Mark so kindly put out.  It puts
>> cement manufacturing contribution at somewhere around  2-3 %  annual
>> global CO2 emissions
>>
>> So although cement is one of the major players in the world?s
>> pollution, and certainly in the construction industry?s
>> contribution, it looks to me that although its present contribution
>> may now be nearer 2-3 % of overall annual global CO2 emissions, its
>> cumulative total effect of all human generated CO2 appears to be
>> nearer 8% ?  does this look right to anybody else?
>>
>>
>> Graeme,
>> Graeme North Architects,
>> 49 Matthew Road,
>> RD1, Warkworth,
>> New Zealand 0981
>> Ph/fax +64 (0)9  4259305
>>
>> www.ecodesign.co.nz
>>
>>
>>
>>
>>
>> --- StripMime Report -- processed MIME parts ---
>> multipart/alternative
>>   text/plain (text body -- kept)
>>   text/html
>> ---
>> ----
>> For instructions on joining, leaving, or otherwise using the GSBN
>> list, send email to GSBN@...HELP in the
>> SUBJECT line. ----
>>
>>
>>
>>
>>
>>
>>
>
> --
> Dr John Straube, P.Eng.
> Associate Professor
> Dept of Civil Engineering &amp; School of Architecture
> University of Waterloo
> Waterloo, ON Canada
>
>
> ----
> For instructions on joining, leaving, or otherwise using the GSBN
> list, send email to GSBN@...HELP in the
> SUBJECT line.  ----
>



Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek@...



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Date: 5 Jul 2007 12:05:21 -0500
From: Mark Piepkorn mark@...
Subject: Re: GSBN:Cemento (combined responses)

At 10:53 AM 7/5/2007, Derek Roff wrote:
>What are some examples of using less Portland cement to do the same job?

         These may not be along the lines you're thinking (and are
generally much smaller in individual scope than what John Straube
addressed, and may fall outside of code), but for instance, dry-laid
or lime-mortared stone stemwall foundations on rubble trenches in
non-seismic areas; earthen plasters with non-portland stabilizers;
natural stone pavers or gravel paths instead of sidewalks where ADA
compliance isn't an issue; wooden or stone steps rather than
concrete. That is, choosing alternatives that don't use portland
cement at all when those choices make sense.

         Again with the Eisenberg: we were in an underground train
station in Washington D.C. some scant years ago and I asked him what
he thought about the huge amounts of concrete around us. He said, "I
think it's great."


>Rob Tom advocated the development of an inside out insulated
>concrete form, where the concrete skins would be on the outside, and
>the foam in the middle.

         Those exist; see
<a  target="_blank" href="http://www.tridipanel.com/";>http://www.tridipanel.com/</a>
and
<a  target="_blank" href="http://www.greensandwichtech.com/";>http://www.greensandwichtech.com/</a>
for examples. I seem to recall that there are insulating-core precast
panels as well. And VariantHouse offers ICFs with imbalanced levels
of insulation from one side to the other - a step in the right direction.


>Rene and maybe Lars talked about using a small amount of cement, to
>cement seashells together, with lots of air gaps. Living near
>volcanoes, pumice-crete uses the same idea, with a little cement and
>a lot of pumice.

         For what uses?

         The website www.pumicecrete.com says that they use "under 3
sacks of portland cement for every cubic yard of aggregate" for a 400
psi product. That's about half the cement of a typical 3000 psi
concrete mix, but might not make a code-compliant grade beam.

         If it's for an insulative wall system, the climate may
suggest that it's an idea worth considering (thinking of Martin
Oehlmann's weather-exposed wall by the sea). But if the shell or
pumice system is so friable and / or so air-gappy that it requires
protection from the elements (like wind-blown rain), or from people
and animals, that an additional coating or covering layer is needed,
the whole thing might want yet another reconsideration.


>A cement grade beam on a rubble trench saves a lot of concrete, with
>potentially superior performance.

         To be fair, I guess we also have to say that a full-depth
concrete foundation offers potentially superior performance to a
rubble trench with a grade beam, too. It just depends.


>Other examples and techniques?

         I was on the phone with the guy from GCS Radiant earlier,
and he said they're using ground-up windshield dust as a
portland-replacing pozzolon in their product. (He claimed that it
partially replaces their portland and isn't just filler. But they
also have fly ash content, so who knows.)

         Precast components can achieve optimal strength through
controlled curing, reducing material consumption by opening the doors
to optimized design for the materials so that field pours aren't
overdesigned. There's also less waste in precast vs fieldcast (no
overage dumping), and there can actually be less transportation
energy since the moisture in a wet mix isn't being transported as well.


Mark


>--On Wednesday, July 4, 2007 9:39 PM -0400 John Straube
>jfstraub@... wrote:
>>I also think one has to consider that cement is just one material
>>that is used. It is used an awful lot, and this is part of its
>>environmental footprint. However, the reason it is used a lot is that
>>it is made of clay and limestone (available most places in quantity)
>>and results in a very durable and low dollar cost product. I am all
>>for reducing cement use, and changing cement manafucturing to
>>dramatically reduce CO2 and other emissions. however, if the
>>replacement for the apartment buildings in China is, for example,
>>steel, then the CO2 emissions will rise dramatically as steel will
>>use more energy and CO2 for the same beam or column. Lots of cement
>>is used in heavy civil works like roads, and sewers, curbs and
>>sidewalks. There are some replacements, but few work as well.
>>At the end of the day, I think cement is one of many materials that
>>we need to use more wisely and hence less of, but for many purposes,
>>it is hard to find an equally durable, non-combustible material that
>>has less impact.
>>One of the clear substitutions is wood framed housing instead of
>>concrete. This works in some places, like where they have trees, but
>>there are limits to height, fire resistance, and durability that are
>>quite practical. For most other applications, like basements,bridges,
>>sewer pipes etc, I think we can gain more by be smarter in its use
>>(optimally designed structures) and dramatically improve is
>>production (e.g. there is little reason why a coal-fired cement plant
>>could not use carbon sequestration.



Mark Piepkorn
www.potkettleblack.com

Wouldn't this be a wonderful world if insecurity
and desperation made us more attractive?
   - Broadcast News



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