<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Dear all</div><div><br></div>Maybe there is confusion here between cement and lime<div><br></div><div>Lime can absorb C02 during carbonation and this can make a small contribution to carbon sequestration over its life in a building</div><div><br></div><div>Cement however does not in most cases as cement works best if it does not carbonate unlike lime. </div><div><br></div><div>The argument that C02 is stored in concrete is a bogus argument put about by the cement and concrete industry to try and greenwash cement.</div><div>The carbonation argument seems to be based on the idea that concrete can be crushed at the end of life and that this has some carbonation benefit</div><div>See</div><div><a href="http://www.sustainableconcrete.org.uk/main.asp?page=85">http://www.sustainableconcrete.org.uk/main.asp?page=85</a></div><div><br></div><div>The C02 is emitted during the manufacture of cement and is not recovered in my opinion . It contributes to fossil fuel energy wastage and global warming</div><div>Even the use of recycled material like ash involves energy though the cement industry have made great strides in reducing this</div><div><br></div><div>Cement manufacture remains one of the highest emitters of C02 in all human activity as alternatives are not being used in many parts of the world</div><div><br></div><div>Pragmattically we probably all use a bit of cement from time to time but it should be avoided if there are better alternatives like lime or earth</div><div>Here is an interesting paper which discusses these issues and compares cement to alternatives</div><div><br></div><div><a href="http://www.springerlink.com/content/56266t21424h4854/">http://www.springerlink.com/content/56266t21424h4854/</a></div><div><br></div><div><b>Calculation of sequestration in wood straw etc.</b></div><div><b><br></b></div><div><b>A paper on this is being prepared by David Robson of University of Cumbria and initial findings have been presented to the UK Renewable Building Group</b></div><div><b>Several GSBN UK members are part of this group</b></div><div><b><br></b></div><div><b>This research will be made available when complete and will hopefully provide some hard data on the sequestration contribution of renewable bio based materials</b></div><div><b><br></b></div><div><b>Tom</b></div><div><b><br></b></div><div><b><br></b><div><div>On 7 May 2010, at 04:13, Mészáros Attila wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Dear All,<br><br>I completely agree with Derek. Though the amount of the reabsorbed CO2<br>could be nearly 50 % of the portland cement's dry mass, the CO2 emission<br>during the production is higher than this amount.<br>The net CO2 production of portland cement production and curing is<br>positive. The whole process does not sink, but produces CO2. It is pure<br>chemistry and physics.<br><br>So I am really surprised on Martin's info on IPCC's perception.<br>I know personaly the hungarian member of IPCC, Diana Ürge-Vorsatz, she<br>is also a physisist.<br>So if we can have a bit more info, we can act. First informal ways, and<br>then even formaly...<br><br>Attila<br><br>Attila Mészáros<br>CEO, CereDom Ltd<br>email: <a href="mailto:meszaros.attila@ceredom.hu">meszaros.attila@ceredom.hu</a><br>tel: +36 20 9772258<br><br>2010.05.06. 23:22 keltezéssel, Derek Roff írta:<br><blockquote type="cite">Thanks, Martin. Could you clarify a bit about this sentence? Do the<br></blockquote><blockquote type="cite">sources that you quoted give an explanation?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">"cement-based products in contrary are accepted to reduce the PCF<br></blockquote><blockquote type="cite">(product-carbon-footprint) as the CO2 used for production is stored<br></blockquote><blockquote type="cite">for a long time."<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">What I find confusing, is that production of cement produces a lot of<br></blockquote><blockquote type="cite">CO2 from fossil fuels in mining, processing, calcining, and utilizing.<br></blockquote><blockquote type="cite">It produces/releases a fair amount of sequestered CO2 from the<br></blockquote><blockquote type="cite">limestone during the calcining chemical reaction. I'm not thinking of<br></blockquote><blockquote type="cite">any point at which "the CO2 used for production" is stored at all. A<br></blockquote><blockquote type="cite">small amount of CO2 is reabsorbed from the air by finished concrete,<br></blockquote><blockquote type="cite">but what I have read is that this is a tiny fraction, and needs to be<br></blockquote><blockquote type="cite">tiny, to maintain the integrity of the concrete.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">So what CO2 storage are they talking about?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Derek<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">--On Thursday, May 6, 2010 9:24 PM +0200 martin oehlmann<br></blockquote><blockquote type="cite"><<a href="mailto:moehlmann@wanadoo.fr">moehlmann@wanadoo.fr</a>> wrote:<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><blockquote type="cite">Dear all,<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">however not much response here on this issue... some possible<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">interesting observations in the meantime:<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">According the perception of IPCC and UN-FCC straw and wood are not<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">seen as CO2-sink, yet CO2 neutral, cause of the durability is<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">“difficult” to calculate. In contrary cement-based products in<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">contrary are accepted to reduce the PCF (product-carbon-footprint) as<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">the CO2 used for production is stored for a long time. (source:<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Memorandum Product Carbon Footprint, German Ministry for Environment,<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Nature Protection etc.)<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Comment: compliments for the cement lobby, low cost cementbased<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">massproduction for housing with a lifespan 30-40 years.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">If planted forests get cut after 30 years and seen as a CO2 sink, a<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">high quality building which lasts 100 years and longer built with<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">natural materials better should be perceived as storage, if the<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">intention from IPCC and UN-FCC is to support sustainable<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">constructions.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Nice day and all the very best,<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Martin Oehlmann<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Brittany<br></blockquote></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Derek Roff<br></blockquote><blockquote type="cite">Language Learning Center<br></blockquote><blockquote type="cite">Ortega Hall 129, MSC03-2100<br></blockquote><blockquote type="cite">University of New Mexico<br></blockquote><blockquote type="cite">Albuquerque, NM 87131-0001<br></blockquote><blockquote type="cite">505/277-7368, fax 505/277-3885<br></blockquote><blockquote type="cite">Internet: <a href="mailto:derek@unm.edu">derek@unm.edu</a><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">_______________________________________________<br></blockquote><blockquote type="cite">GSBN mailing list<br></blockquote><blockquote type="cite"><a href="mailto:GSBN@greenbuilder.com">GSBN@greenbuilder.com</a><br></blockquote><blockquote type="cite"><a href="http://greenbuilder.com/mailman/listinfo/GSBN">http://greenbuilder.com/mailman/listinfo/GSBN</a><br></blockquote><br><br>_______________________________________________<br>GSBN mailing list<br><a href="mailto:GSBN@greenbuilder.com">GSBN@greenbuilder.com</a><br>http://greenbuilder.com/mailman/listinfo/GSBN<br></div></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="font-size: 12px; "><div style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div>Tom Woolley</div><div><br class="khtml-block-placeholder"></div><div>Rachel Bevan Architects</div><div>80 Church Road</div><div>Crossgar</div><div>Downpatrick</div><div>BT30 9HR</div><div><a href="mailto:tom.woolley@btconnect.com">tom.woolley@btconnect.com</a></div><div>028 44 830988</div><br class="Apple-interchange-newline"></span></span></div></span> </div><br></div></body></html>