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Dave Bennett
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I just ran across this and thought some might be interested. It isn't on the market yet but it is coming.
http://novacem.com/technology/novacem-technology/
 
Brian Knight
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Thanks for the link Dave. Concrete is such a great construction material its good to see that people are working on its carbon impact.

Iam a skeptic of anything claiming to be carbon negative and I think its a marketing mistake to make such wild claims.

One of the best ways to reduce the impact of concrete is to use fly ash in the mixture. This displaces the amount of concrete that needs to be produced and is a decent solution to the problem of that coal byproduct.
 
Dave Bennett
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Springtime Homes wrote:Thanks for the link Dave. Concrete is such a great construction material its good to see that people are working on its carbon impact.

Iam a skeptic of anything claiming to be carbon negative and I think its a marketing mistake to make such wild claims.

One of the best ways to reduce the impact of concrete is to use fly ash in the mixture. This displaces the amount of concrete that needs to be produced and is a decent solution to the problem of that coal byproduct.

I understand you skepticism but it sounds pretty striaghtforward to me. They use biomass for fuel and feed the CO2 from the heat source into the retort as I understood what they stated. I have lots of issues with cement production I wonder if using the fly ash would contaminate the concrete because fly ash is full of heavy metals. My biggest issue with cement though is the mercury produced by burning the coal. That winds up in the water and never goes away. I would love to see enough alternative electricity production to make cement without burning any fossil fuels. That would make ordinary concrete an excellent green building material. I am not as skeptical as you are since I know that ethanol made from hemp is carbon negative as is ethyl ester biodiesel made from hemp. It does look promising though. Even hempcrete made with raw limestone is carbon negative.
 
Brian Knight
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I definitely feel its a step in the right direction but there is nothing straight forward about being "carbon negative". One of concrete's most important ingredients is aggregate (gravel). Are they crushing and screeding the aggregate and limestone with biomass fuels? Are they using 100% bio fuels to transport all their materials including the mixer to the jobsite? Are they using renewable fuels to pump the needed water?

I wont speak on the carbon analysis of ethanol or hemp biodiesel but I suspect a holistic view as above would make it a tough case for being truly carbon negative. I will question the Carbon Negative claims made by the hempcrete people as I have witnessed the first two N.American projects go up here in Asheville NC. The raw hemp was transported from the UK... case closed. Even if it was grown in Canada (or hopefully soon in the US) I still dont feel it would truly be carbon negative. There are the tricky scientific theories behind how the walls absorb carbon as the walls breathe. This "breathing wall" theory seems to be only held by a certain portion of people in the UK and a small handfull of followers here in the US. Most Building Scientists will have a hard time accepting "breathing walls".

My main argument is something I am very familiar with: Labor Costs and Hidden Costs. The two projects I saw involved HUGE amounts of labor and took a long time to complete. Big crews of workers came every day to the job site for weeks and I doubt any of them were fueling with B100. Luckily these carbon costs were minimized by being infill projects, but this was a pretty substantial hidden carbon cost that my SIP homes do not incur. Another very difficult to calculate hidden carbon cost is the fuel that it took these workers to complete their labor (food). Also, the hempcrete required a fossil fuel cement mixer to mix the lime and hemp shive and it seemed to run quite a bit. I dont think Hempcrete is including these many costs in their "carbon negative" calculations.

 
Brian Knight
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I share your concerns with using fly ash in concrete. I seem to remember smarter and more paranoid people than me saying that heavy metals from fly ash in concrete do not show up in any relavent testing but have nothing to back this up. I think the main reason its a green practice is that it encapsulates the fly ash and so it does not introduce its heavy metals via coal ash ponds or spills as happened in the 2008 TVA disaster.

Despite its high carbon impact, I think its one of the best construction materials we have. Its apparently THE most used man made material in the world in terms of volume. Hopefully, companies like the one you brought to our attention will continue to reduce the negative impacts of this very valuable material.

Link describing 2008 TVA Coal Ash Spill: http://www.springtimehomes.com/green_building_hidden_costs#Toxic Spill
 
Dave Bennett
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If you looked at the website and actually read what they discussed you would see that the product is CEMENT and not concrete. Your arguments about aggregate are not relevant regarding this product. THEY are not producing concrete but cement. I am not going to get into a debate regarding hemp because you left out the most important part of why hemp is carbon negative. Growing hemp sequesters more carbon than most other growing plants because of it extremely high rate of respiration. My data is not from Great Britain but an understanding of how the lime reacts in the setting process. Even portland cement sequesters CO2 as it sets but the difference is that of density so concrete sequestered a minimal quantity of CO2. As far as the other comment about concrete being the best building material available I have been down that road on this site with others promoting concrete with is tremendously filthy and not green in any way.

I made this post because of the promise of a green cement product. As for the hempcrete building in NC using the Very First Buildings in the US as ammunition for how it is not green is not exactly fair by any stretch of the imagination. Using transportation use of petroleum is moot also since transportation of concrete uses the same fuels. I did not put this post here to get in any arguments about what's carbon negative and what is carbon positive and will not participate in that manner. This is a positive step towards a green cement and I like it.
 
Brian Knight
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Okay Dave, well spoken. I honestly thought both them and you were using the wrong terminology by using "cement" instead of "concrete". My bad.
 
Dale Hodgins
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I had all of the same concerns as Springtime Homes. The amount of information given on that website is minimal. It appears to be a mini prospectus in search of funding. I would have to see at least 100 times as much info for it to be useful to me. I want to see where they get those other raw materials and what the mining process was. Mostly I want to see information corroborating what they say from unbiased sources.

Any time hemp is brought up it's bound to get eyes rolling. I almost stopped reading when I saw the word. I lived beside a hemp field in Ontario. Yes it was productive but no it was not ten crops a year with no inputs. I've sat and listened to kids tell me that it produces vastly more than what I witnessed.

If they have something that's great. But I remain unapologetically skeptical for now.
 
Dave Bennett
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Dale Hodgins wrote: I had all of the same concerns as Springtime Homes. The amount of information given on that website is minimal. It appears to be a mini prospectus in search of funding. I would have to see at least 100 times as much info for it to be useful to me. I want to see where they get those other raw materials and what the mining process was. Mostly I want to see information corroborating what they say from unbiased sources.

Any time hemp is brought up it's bound to get eyes rolling. I almost stopped reading when I saw the word. I lived beside a hemp field in Ontario. Yes it was productive but no it was not ten crops a year with no inputs. I've sat and listened to kids tell me that it produces vastly more than what I witnessed.

If they have something that's great. But I remain unapologetically skeptical for now.

That far north hemp doesn't have a long enough growing season and I have never seen anywhere that it can produce 10 crops per year. I do know for a fact that in some areas with a reasonable growing season that 3 crops per year are easily possible maybe 4 far enough south but not in Canada. Using Canada as an example of what would be possible here in the US is unreasonable. I have some friends in Ontario that grow sweet potatoes and if you ask most people they will tell you that it isn't possible. Roll your eyes all you want I have done my homework and not by using Canada as an example other than I have seen some hemp farms out in Sas. that are run as if they were growing wheat. Henry Ford got 2 huge crops per year in Michigan way back when without using any fertilizer. I did not want to get into a "contest" but it seems as if whenever anyone tries to post anything about concrete here it turns into a huge debate. It just isn't worth it to try to help out on this thread.
 
Mark Anderson
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I don't know if anyone has mentioned this but there is a product called ceramicrete or grancrete that looks promissing.
 
Charlie Rendall
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I saw a documentary many years ago about how for a long time archaeologists had no idea what cement had been used in the Great Wall of China and they finally discovered they'd been using some form of rice cement! I think they found microscopic bits of rice husks and then a chemical analysis to determine this. I'd love to know if anyone knows what it was or how to make it, since it's clearly very durable. As for its carbon neutrality, well, we can determine that later

p.s. My two cents on the whole Novacem debate above: I think constructive skepticism of new products is a very healthy aspect of permies (and web forums in general), especially with so much greenwashing going on these days - maybe Novacem is a genuine green solution, maybe not, but yes at least it's a step in the right direction in as much as there's an acknowledgement that we should be developing ways of making cement production more sustainable. And I think such debate is also a step in the right direction, we should be asking those questions. Let's hope we find out soon just how green it really is so we can either reject it or start using it!
 
Dave Bennett
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Personally I have been collecting grain bags to use for an earth bag structure. The only real green part about it is that those bags that are made from some synthetic material (polyester I suspect) aren't going to the landfill. I have several thousand of them so far. They are few for the asking at almost any micro
brewery. I have been experimenting with a plaster made from crushed limestone and skim milk to use as a coating for my structure. I got the idea because I make my own milk paint so I just made a very thick paste instead. Milk paint with added raw Tung Oil is incredibly weather resistant so I added some Tung oil to my plaster. It is still out in the yard being weather tested. The casein in the milk seems to add structural integrity to the limestone "mud."
 
                        
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g'day dave,

yes fly ash has some nasties in it and worse over here all our cement dust is manufactured using fly ash, and people buy cement tanks, ok they use the cement to make septic tanks but dunno about drinking out of them

also as the cement dust manufacturer is not near the power stations this material gets trucked continually daily from power house to where the cement dust is made.

len

http://www.lensgarden.com.au/
 
Marcus Zed
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Springtime Homes wrote:My main argument is something I am very familiar with: Labor Costs and Hidden Costs. The two projects I saw involved HUGE amounts of labor and took a long time to complete. Big crews of workers came every day to the job site for weeks and I doubt any of them were fueling with B100. Luckily these carbon costs were minimized by being infill projects, but this was a pretty substantial hidden carbon cost that my SIP homes do not incur. Another very difficult to calculate hidden carbon cost is the fuel that it took these workers to complete their labor (food).


I think it is important to disaggregate these factors when looking at a building system overall, and integrate them only according to the circumstances of a particular project.

I can see the requirement of a large off site labor force and it's attendant transportation use being a point of comparison of the carbon impact of differrent systems in a particular project, but not in all projects. Transporation cost is relative to the remoteness of the site. A more labor intensive building system might be more appropriate to projects sited close to an available labor force. In contrast, a building system which uses "on-site" materials in a remote undeveloped area might have a greater co2 impact if a massive bulk of soil/clay/haybales had to be trucked in to an urban building site.

If someone is selling concrete (cement?) and calling it "green", the appropriate comparison is to the standard concrete products it claims to replace. A good understanding of the impact of the concrete component itself can then be inserted into the carbon calculation of a given project.

Suppose I wanted to use this "green concrete" to pour footings for a small structure. In that case, I would probabally be able to mix the necessary quantity of concrete by hand. It would be inaccurate in that case to use co2 figures for the product which assume the use of a motorized cement mixer in figuring the overall carbon impact of the project.

The final factor named here is troubling: Food.

The workers in question were not bred for this one project, nor do they sit in stasis somewhere waiting for someone to hire them.

Would you state the converse: "Because I chose to not build with such-and-such method, 20 cement masons and their families did not eat today... Hooray for Permaculture!!!" ?
 
Brian Knight
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I agree Marcus. I will retract it as its a minor consideration in the big picture of Labor Costs. I (think) I was trying to make the point that Labor Costs have many hidden environmental costs. I think its possible that the hidden environmental costs of a labor forces food needs could be bigger than the impacts of that labor forces transportation. Construction is generally high calorie work and its workers are not generally know for their environmentally responsible food choices. If for example, one of my houses only takes 3 workers with 2 weeks to dry in, the impact of that food production is going to be much less than a competing project that takes 15 workers 4 weeks to dry in. In terms of food resources (which also have many hidden costs), the project with less labor has less environmental impact. I think youre generally right though; "Remoteness of site" vs "infill development" is a much bigger hidden cost variable...
 
Marcus Zed
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Your critical method of searching widely for hidden inputs seems correct on a project basis.

I suspect that the "green concrete" skeptics on this thread are trying to get ahead of potential perverse interpretations like: "We need to quit telling people to build with cob, which is merely carbon NEUTRAL, and encourage them to build everything out of this new carbon NEGATIVE cement!!!"

Of course, the sort of simplistic thinking that would lead to that kind of attitude is unlikely to coexist in the same mind that would be receptive to your more complicated model.
 
Dave Bennett
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Marcus Zed wrote:Your critical method of searching widely for hidden inputs seems correct on a project basis.

I suspect that the "green concrete" skeptics on this thread are trying to get ahead of potential perverse interpretations like: "We need to quit telling people to build with cob, which is merely carbon NEUTRAL, and encourage them to build everything out of this new carbon NEGATIVE cement!!!"

Of course, the sort of simplistic thinking that would lead to that kind of attitude is unlikely to coexist in the same mind that would be receptive to your more complicated model.

Nobody that I know of implied using this potential product instead of cob. Cob is not available everywhere. I made the original post because I ran across it and it looks promising which then turned into some sort of a "measuring contest." Cob is also extremely labor intensive and in fact if it is contracted costs more per sq. ft. than conventional building techniques. I reiterate, the post was made because I ran across a building product that looks promising.
 
Marcus Zed
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Dave Bennett wrote:Nobody that I know of implied using this potential product instead of cob.


Wasn't saying you (or anyone else) did. I was just trying to puzzle out the responses.
 
Dave Bennett
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So far it has been my experience posting on this thread stating anything negative about just how filthy Portland cement is when considering permanent pollution especially from mercury is like setting the holy grail on fire. Mention anything remotely resembling the possibility of carbon negativity and suddenly everybody becomes an expert skeptic. I find it interesting for instance that so much time was spent pointing out the food aspects and transportation fuel costs when I mentioned hempcrete but completely ignored how much carbon is actually sequestered during the growth cycle of the hemp in the first place. Looking at one part of a picture and making blanket statements only demonstrates a negative attitude. It is just not worth discussing anything on this thread that flies in the face of Portland cement. The thread title is green building and I tried to contribute to the discussion but have become tired of the skepticism. I give up.
 
Brian Knight
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Never give up Dave! Your link was appreciated as is this tricky topic of greening an energy intensive building material. Energy use-Food-Transportation. They are all connected and need to be addressed if our society is going to continue at its present course.

If we are to use our valuable farm land to sequester carbon while providing building materials I would think any large scale production would negatively effect food production. Sorry for being negative.
 
Walter Jeffries
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Concrete is already a very 'green' building material. It is made up almost entirely of local stone and sand. There is a small percent of cement to bind it together. Then it is even greener because you build with it and it can last hundreds to thousands of years.
 
                        
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g'day walter,

there are probably 2 issues here one is the making cement poweder that is blended with sand and gravel to make the cement/concrete mix we use in buildings.

as a permaculturist i see it that there is no free stuff ie.,. sub-aquafa water and sand gravel soil to build homes with, all these products are habitat, lots of sand and gravel comes from creeks and rivers, but all of it is habitat, even destroying forest habitat to grow plantation timbers to build houses is using habitat to the detrement of wild life, especially so over here. so we need to get more sustainable in what we do in this modern world. growing food on broad acre farms where all habitat has been removed, pushing down forests to grow oil palms.

len
 
duane hennon
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here is a site about "green concrete" with 30 yrs experience

this page talks about a simple to make concrete

http://www.geopolymer.org/applications/ltgs-brick-low-cost-construction-material

check out the whole site, esp the concrete used in the pyramids!!!
 
Walter Jeffries
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gardenlen gardener wrote:as a permaculturist i see it that there is no free stuff ie.,. sub-aquafa water and sand gravel soil to build homes with, all these products are habitat, lots of sand and gravel comes from creeks and rivers, but all of it is habitat, even destroying forest habitat to grow plantation timbers to build houses is using habitat to the detrement of wild life, especially so over here. so we need to get more sustainable in what we do in this modern world. growing food on broad acre farms where all habitat has been removed, pushing down forests to grow oil palms.


And as a permaculturist I see myself as part of the ecosystem, using materials just as the beaver, bear, deer and wolf, to adjust the system for my needs. We are not separate from nature, we are a part of it. In the big scale of things, the permaculture, a human life and even an entire civilization is but a blink of the eye. I don't destroy forest, I use it and adjust it. I cut some just as the beaver and forest fires clear - this creates margins that are the places of highest biodiversity in our climate. I don't destroy creeks and rivers to get gravel, those materials. You're just sorely missunderstanding reality.
 
                        
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This discussion reminds me a little of the storm that was set loose when it was suggested that at least a portion of the pyramids were cast rather than made of huge limestone blocks somehow fitted into place. So then the guy proceeded to prove his point by casting a huge stone using the materials and techniques available in Egypt at the time the pyramids were built. The thing is a huge stone block. With the same characteristics of any natural stone of the same type. Built in France without any supplemental heat, just dried by the sun. However, since it was made to make a specific point, the materials were brought to France from the Mediterranean.

At first glance, ( I didnt read it with a lot of care, admittedly) the link above suggests to me that theese guys are using a modified version of the same process. There are a dozen or more combinations which work WITHOUT any heat aside from the sun, in hot/sunny areas. Bricks are made which can be fired by piling them under black plastic in the sun which will behave absolutely comparably with similar building material. Much of this research was done in Africa as an effort to help with housing but he says that the equivilent is available anywhere. The bonding takes place because of the same sort of chemical reaction that happens in a cake to eggs and butter and flour; the interaction between the ingredients creates a product entirely different and the ingedients become individually unrecognizable. There's lots of info on his site but I don't have enough chemistry to follow and modify to use the comparable materials in my area.

When I first read the comment about the cement used in China momentarilly I had a thrill of hope...I have been trying to find out more about that for about two years! Only thing I can add is that it seems to have been a proportion of specifically sticky rice to the water..cooked I assume but not sure, maybe it was just soaked. What the proportions ( I think 3% was mentioned somewhere) and other ingredients were in their proportions I haven't been able to discover. The cement was also used for buildings walls and bridges in China which are still extremely stable and strong.

As far as portland cement being green that 's a scary thought. Once it's MADE, then fine, but the process is hugely polluting not only with carbon but also other somewhat more ominous chemicals released into the air which directly impact human health for miles around the manufacturing areas. Also, modern concrete certainly strong but it is not entirely the ultimate answer, when it breaks or fails it is not easilly recycled, and indeed it DOES fail for a number of reasons. You have seen photos of the bridges failing in earthquakes, of buildings which fail because of water penetration are two examples. It has certainly made some types of construction possible but it's time now, imo. that we learn how to do better than something invented well over a hundred years ago. Just as we have learned that burning coal is not the optimum way to heat our homes, it's perhaps time to move on from portland cement as we now know that the production of cement is highly antagonistic to health.
 
                        
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Ah Duane I must have been typing my reply just as you were doing yours
 
Walter Jeffries
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Pam Hatfield wrote:process is hugely polluting


Yet you're missing the point. The cement is not the concrete. Cement is just a small part of the concrete. Fanatics like to paint with a broad over generalizing brush like this and confuse the issue by mixing the terms.

Pam Hatfield wrote:modern concrete certainly strong but it is not entirely the ultimate answer, when it breaks or fails it is not easilly recycled, and indeed it DOES fail for a number of reasons.


That was rather a non-proof. Anything done wrong can fail. You're using anecdotal evidence in the negative which is an easy way to fail your argument. The fact remains that done right, and it usually is, the concrete does not fail but far out lasts other materials. Go ahead and try to build the things that have been built with concrete using wood and see how long they last. Maybe you would rather use wool? Animal hides? That will make a great, long lasting bridge. Not.

Improvements in cement production (it's cement, not concrete) are very good. Don't confuse the issue with false arguments.
 
                        
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Walter Jeffries wrote:
Pam Hatfield wrote:process is hugely polluting


Yet you're missing the point. The cement is not the concrete. Cement is just a small part of the concrete. Fanatics like to paint with a broad over generalizing brush like this and confuse the issue by mixing the terms.

quote]

http://www.thedailygreen.com/environmental-news/latest/mercury-cement-47012002 I was not confusing the two at all. I would definitely prefer not to have mercury (among other things) being spewed into the air no matter how little cement, relatively speaking, is used to build a house. The point is that although each project may only take a little the number of projects add up to a whole lot. It's like each guy only killed one passenger pigeon but somehow the passenger pigeons went from being in the uncounted thousands to being exterminated. Finis. It's the cumulative effect.

As far as the failures are concerned are you suggesting that the bridges and abutments on the highways in California were all built incorrectly? Or all the buildings in Haiti which collapsed? Those are only two examples. Cement is what holds the concrete together, there is nothing else, so if the concrete fails, that is, doesn't hold together, it is the cement part of the concrete which is to blame. Nobody would ever expect sand and gravel to cohese at all otherwise. But, concrete is brittle and though very strong cannot manage flex or certain sorts of stresses, which is why it's virtually always used with rebar of some sort. Sometimes even that isn't enough.

Another problem is that concrete made with portland cement is also very vulnerable to water , especially in areas where water is likely to freeze, which is why there are thousands of companies which fix leaky basements and crumbling foundations and dozens of products sold to waterproof it. Or to try to clean mould from it.

As far as bridges are concerned, there are many many wooden bridges which have been in use for a very long time. There is one in Switzerland, still in use today, which was built in the 1300s. (admittedly much of it was restored..after a fire in 1993). 600 + years and going strong will do me just fine. As far as I can tell ALL bridges, concrete/steel or otherwise, need maintenance and repair from time to time. Certainly I've been held up in traffic on not a few concrete and steel bridges, often not more than a few years old, because of repair crews doing maintenance. Are you saying they were ALL improperly built? As far as that goes, a guy in Japan built a totally serviceable bridge out of paper, although it was a demo project and only used for foot traffic, not vehicles.

It seems to me that pointing out there are two sides to the story and that cement (in the form of portland cement at least) is not the unalloyed answer to all building problems, is hardly being fanatical. It would be unfortunate to think we cannot get beyond the technology of the 19th century now we are in the 21st. Or maybe we should go back further and learn what the people of the deserts did 3000 years ago when they constructed water tanks still in use today.

 
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