[GSBN] embodied energy comparisons

[Mészáros Attila]

Dear All,

I completely agree with Derek. Though the amount of the reabsorbed CO2
could be nearly 50 % of the portland cement's dry mass, the CO2 emission
during the production is higher than this amount.
The net CO2 production of portland cement production and curing is
positive. The whole process does not sink, but produces CO2. It is pure
chemistry and physics.

So I am really surprised on Martin's info on IPCC's perception.
I know personaly the hungarian member of IPCC, Diana Ürge-Vorsatz, she
is also a physisist.
So if we can have a bit more info, we can act. First informal ways, and
then even formaly...

Attila

Attila Mészáros
CEO, CereDom Ltd
email: meszaros.attila at ceredom.hu
tel: +36 20 9772258

2010.05.06. 23:22 keltezéssel, Derek Roff írta:
> Thanks, Martin. Could you clarify a bit about this sentence? Do the
> sources that you quoted give an explanation?
>
> "cement-based products in contrary are accepted to reduce the PCF
> (product-carbon-footprint) as the CO2 used for production is stored
> for a long time."
>
> What I find confusing, is that production of cement produces a lot of
> CO2 from fossil fuels in mining, processing, calcining, and utilizing.
> It produces/releases a fair amount of sequestered CO2 from the
> limestone during the calcining chemical reaction. I'm not thinking of
> any point at which "the CO2 used for production" is stored at all. A
> small amount of CO2 is reabsorbed from the air by finished concrete,
> but what I have read is that this is a tiny fraction, and needs to be
> tiny, to maintain the integrity of the concrete.
>
> So what CO2 storage are they talking about?
>
> Derek
>
> --On Thursday, May 6, 2010 9:24 PM +0200 martin oehlmann
> <moehlmann at wanadoo.fr> wrote:
>
>> Dear all,
>>
>> however not much response here on this issue... some possible
>> interesting observations in the meantime:
>>
>> According the perception of IPCC and UN-FCC straw and wood are not
>> seen as CO2-sink, yet CO2 neutral, cause of the durability is
>> “difficult” to calculate. In contrary cement-based products in
>> contrary are accepted to reduce the PCF (product-carbon-footprint) as
>> the CO2 used for production is stored for a long time. (source:
>> Memorandum Product Carbon Footprint, German Ministry for Environment,
>> Nature Protection etc.)
>>
>> Comment: compliments for the cement lobby, low cost cementbased
>> massproduction for housing with a lifespan 30-40 years.
>>
>> If planted forests get cut after 30 years and seen as a CO2 sink, a
>> high quality building which lasts 100 years and longer built with
>> natural materials better should be perceived as storage, if the
>> intention from IPCC and UN-FCC is to support sustainable
>> constructions.
>>
>> Nice day and all the very best,
>>
>> Martin Oehlmann
>>
>> Brittany
>
>
>
> 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 at unm.edu
>
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