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Re: GSBN:Cemento



Thanks all (especially Mark) for the info on cement.

Since I jumped into construction directly with strawbale, instead of "converting" from conventional construction, I have had no personal experience working with cement.  From what I have read/seen it is only "necessary" to use cement if you can´t afford to use lime, and wherever it is possible use clay instead of lime (which almost always is an industrial process and uses fuel).  I refer to the typical "The Romans didn´t use cement, and look where it got them..." Of course I only work on small buildings...

By the way, I have no idea what "Fly Ash" is, so can't say if its used outside of the US or not...

Check out the book "Radical Simplicity".  Its time we un-complicate our lives.

Rikki


-----Original Message-----
>From: Martin Hammer mfhammer@...
>Sent: Jul 2, 2007 10:52 PM
>To: GSBN GSBN@...
>Subject: Re: GSBN:Cemento
>
>Mark - 
>
>Thanks for that great and thorough article about concrete from the archives
>of the Environmental Building News.
>
>Rikki, I second Mark's recommendation that you obtain Bruce King's terrific
>book "Making Better Concrete".  (see the website of his Green Building Press
>- www.greenbuildingpress.com).  The last chapter "Why Use Fly Ash?", is what
>is most relevant to your question about the downsides of cement.  The rest
>of the slim book is a thorough look at substituting fly ash for cement in
>concrete.  In order to use less cement (replacing it with the industrial
>waste product of fly ash or a natural pozzolan) AND to get better (in many
>ways) concrete.
>
>I wonder how available and how often fly ash is used outside the US, and was
>interested to hear Chris Stafford's comments about it becoming less
>available/suitable in his (northwest) part of the US.  And about a move to
>import it from the Philippines (!?)
>
>Concrete does have many incredible characteristics, and is tempting (and
>sometimes necessary?) to use as a building material.  But if your goal is to
>minimize the use of cement, then substituting fly ash is one way.  Of course
>minimizing or not using cement and concrete at all is another.  (By the way,
>I'm an advocate of rubble trench foundations.)
>
>We all decide how far to take the quest to create the greenest buildings we
>can.  So I'll just state what I see as the limit - that the greenest
>building is no building at all.  Not a lot of fun or very creative, but if
>you're talking exclusively about doing the best thing environmentally, it's
>had to argue with nothing.
>
>Except maybe to restore or clean up some place that has already been
>damaged.  And thus: Restore, Reduce, Reuse, Recycle  (in that order).
>
>Last week a "plan checker" who was reviewing two straw bale houses I
>designed presented the friendly challenge that, in environmental terms,
>straw bale buildings are a case of the "the emperor's new clothes" (from the
>Hans Christen Andersen tale, where the emperor claimed to be wearing
>beautiful clothes, but actually had nothing on).  That they aren't
>particularly green if they are large or use a lot of concrete, or depending
>on other materials they use.
>
>Of course he's right.  So just a reminder to always ask ourselves what is
>truly "green", and consider the indirect aspects and issues that aren't
>often mentioned, like land use, material durability, etcetera . . . .
>
>So if you can't build nothing, and must build something, then simply build
>as green as you can.  (Not that you aren't already.)
>
>Martin Hammer
>California
> 
>
>
>
>> At 08:33 AM 6/24/2007, Rikki  Nitzkin wrote:
>>> I know all the arguments, but I don´t have any
>>> firm statistics from reliable sources to back up my arguments.
>> 
>> The text of a 1993 article from Environmental
>> Building News, without its charts and diagrams, follows below.
>> 
>> On the whole, the cement industry hasn't changed
>> a lot since the article. One thing to note is
>> that in the U.S., we import a lot of cement -
>> it's not always a local or even regional product.
>> We even bring it over from China.
>> 
>> We had a couple higher-ups from the Portland
>> Cement Association's sustainability task group -
>> yes, they actually have one - in our offices last
>> year. They didn't have horns and tails, and were
>> surprisingly forthright in acknowledging their
>> industry's shortcomings. Doesn't mean that we
>> don't use way too much concrete in the built
>> environment, though. For their spin, see www.concrete.org
>> 
>> I'd like to recommend Bruce King's book, Making
>> Better Concrete: Guidelines to Using Fly Ash for
>> Higher Quality, Eco-friendly Structures.
>> 
>> - - - - -
>> 
>> Cement and Concrete:
>> Environmental Considerations
>> Feature - Environmental Building News March/April 1993
>
>
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