[Greenbuilding] Concrete (was bio bricks?)

Sat Mar 14 10:26:47 CDT 2015

I did some quick searches to learn more about the CO2 emissions from the production of concrete.  Where as this bio brick is using a biological process to create the bond of aggregate that they claim achieves concrete like strength, the material they are replacing is clay which does not release CO2.  This look like a great idea.  I hope it succeeds.  It is the burning of the furnace to bake the traditional brick that releases CO2.  However, real concrete does emit CO2 as a chemical reaction of calcination.   

http://blogs.ei.columbia.edu/2012/05/09/emissions-from-the-cement-industry/
quote from above link:

The direct emissions of cement occur through a chemical process called calcination. Calcination occurs when limestone, which is made of calcium carbonate, is heated, breaking down into calcium oxide and CO2. This process accounts for ~50% of all emissions from cement production.

This article goes on to describe a process of capturing CO2 emissions for factory formed concrete and incorporating it into the concrete itself.  Quite clever.  However, a normal temperature process such as these bio bricks would have that beat.  My question is can the bio brick achieve the 4k or 5k  psi strength and achieve the porosity of a low water/cement ratio concrete used to make water resistant finish.  This is what would be needed for prefabricated concrete wall panels such as Superior Wall.  

With respect to concrete in general, it creates an extremely durable product.  My vision of a sustainable ecologically driven economy, is we would build for permanent value.  In the ideal, we stabilize the population, develop a contraction economy the avoids waste and the need to create more new stuff.  If we have a building stock that meets the needs of the population, there is no demand for more.  There will always be a need to adapt what ever we leave behind to their new circumstances.  That is why I like concrete formed into products that can be efficiently recovered and reconfigured without remanufacturing.  This is like Legos.  Segmented blocks for retaining walls, and masonry pavers for paving and sidewalks are examples of materials that can be reconfigured without remanufacturing. Urban renewal would disassemble and reassemble to same material, avoiding the environmental cost of remanufacturing.  I see concrete panels such as Superior Wall allowing for this possibility.  However, new concrete bridges to accommodate unsustainable automobile lifestyle is only temporarily beneficial and permanently harmful in the CC2 emissions.  

“We are made of star stuff”, Carl Segan

Eli 

From: conservationarchitect at rockbridge.net 
Sent: Monday, March 09, 2015 11:32 AM
To: 'Green Building' 
Subject: Re: [Greenbuilding] bio bricks?

I wonder if this technique could include reinforcing to replace concrete, such as concrete panels like superior wall?  I am aware that concrete is high co2.
Eli 

From: John Salmen 
Sent: Sunday, March 08, 2015 9:42 AM
To: 'Green Building' 
Subject: Re: [Greenbuilding] bio bricks?

This reminds me of some of the ancient techniques for making earthen floors; bacteria, anaerobic conditions etc..

From: Greenbuilding [mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of Bob Waldrop
Sent: March-07-15 5:22 PM
To: Green Building
Subject: [Greenbuilding] bio bricks?

Beginning with sand, a liquid mixture of bacteria, nitrogen, food for the bacteria, a calcium source, and water are added.  Over 5 days, the liquid is gradually added until the food and water run out and the sand dries.  At that point, it is a concrete brick, with strength comparable to anything that has come before.

https://www.minds.com/blog/view/418891791245250560/award-winning-low-footprint-bricks-grown-with-sand-and-bacteria-it039s-a-big-deal

Bob Waldrop, Okie City

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