497 Main Road
Glenorchy
Tasmania 7010 Australia
Phone: 61 3 62497868 (am)
Phone: 61 3 62713000 (pm)
Fax: 61 3 62730010
www.tececo.com

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Keeping you informed about the TecEco cement project.   Issue 23,   24th November 2002

TecEco News

Test Results at Last

We now have veneer blocks on the market made by Island Block and Paver that meet the Australian standard of 8 mpa for a lightweight block.

As the individual blocks tested 12.5, 11.5, 11.8, 14.9, 16.1 and 13.1 mpa we are confident that we can easily achieve the 15 mpa standard.

Thanks to Bill Fawdry and his crew for their perseverance. Probably the most interesting part of this whole exercise was that the factory manager said they were easier to make than conventional blocks!

TecEco Release Intellectual Property (IP) to the Public Domain

After much agonizing and some hesitation TecEco decided to release the details of our TecEco cements to the public domain. This means that we will have to rely on our patents. As we believe them to be strong but not perfect there should not be too much downside risk. To minimize risk of infringement TecEco also plan to keep license fees low.

Research Going on All over the World

As a consequence of the release of the details of TecEco cement technology to the public domain we now have a number of students all over the world studying from PhD's to undergraduate projects.

The university of Technology, Sydney through professors Alek Samarin and Abhi Ray have in particular shown strong interest.

Private individuals and corporations are as well undertaking experimental work.

If you are a student or know a student looking for a project - please get in touch with us. It is essential that TecEco initiate student research now so that at some time in the medium term there is a body of opinion regarding the TecEco technology. Without such a body of opinion it is unlikely that change to concretes generally will occur as formula based standards still rather archaically apply.

Cement Plant

The manufacture of our cement plant has been undertaken by Delta Hydraulics on behalf of TecEco.

The plant will utilize another patent lodged by the company whereby grinding and calcining are combined in the one operation thereby enabling the capture of CO2 and resulting in greater efficiencies.

Establishment of Office

A builder has been engaged by John Harrison our MD to prepare a property at Granton for our first office/factory/research facility. Granton has been chosen because John has agreed to make available a number of allotments in the area for experimental houses and because it was already used as a concrete factory.

Publicity and New Appointment.

Dr. Vivian Mawson, a well qualified writer and shareholder will be assisting John Harrison with the web page rewrite and to catch up on a number of articles requested by journals etc. The last was from a Croation Newspaper!

TecEco will also be filming for Discovery channel early in December. The likely scenario is an interview with professor Abhi Ray, interview with John Harrison, filming at Island Block and Paver, Breadlebane and on a construction site (probably at Greg Perry, a shareholder's house) in Hobart.

This may be followed by an interview with a Canadian associate as Discovery Channel operate from there.

This is a tremendous opportunity for publicity, hopefully nothing goes wrong.

Other Appointments

A number of interviews have been conducted however nobody suitable has yet become available. We are still looking as a matter of urgency to fill the position of first employee. This is a very difficult position to fill as our needs are many and we require as multiskilled person as possible.

Funding

It has been a busy year lodging patents, finding the finance for them, rewriting the chemistry and researching the new patent application. With the appointment of our first employee John Harrison our MD will turn his attention to fundraising again after Christmas as it is essential that ongoing funds are raised to maintain the momentum.

New Web Site

A new web site, CO2Busters.org is well worth a visit - especially since our webmaster, JJ wrote it during his spare time. Please make a visit, post an article or start a discussion thread.

The Geopolymer 2002 Conference

John Harrison attended the Geopolymer 2002 conference in Melbourne recently and it was an excellent chance to catch up with many in the cement industry.

Geopolymers are an ancient material rediscovered in the 50's and examined more intensely since the seventies. Properties such as fire resistance make them ideal for niche applications.

Geopolymers are however still way off making it to general construction usage. Probably much further off than TecEco cements because of the highly precise conditions under what they must be made. The amount of water for example affects the alkalinity which in turn affects the geopolymeric reaction.

The Extent of Carbonation in Concretes

The amount of CO2 concretes absorb is dependent on a number of factors.

Thickness is the key factor - only the outer 35-50 mm (11/2 to 2") of poured Portland Cement and somewhat less for TecEco modified Portland cement concretes will absorb CO2. Concrete masonry units and mortars are on the other hand more permeable and will generally absorb CO2 throughout.

Portland Cement

The curing reactions which occur in Portland cement involve the formation of Portlandite and calcium silicate hydrates. Over time, fully cured cement absorbs CO2 from the air, converting the Portlandite and some of the calcium silicate hydrates to calcium carbonate. Unless pozzolans have been added about 20 - 25% of cured cement is Portlandite, but not all of it carbonates, so a figure for carbonation of around 20% is typical near the surface and for thinner structures. The formation of calcium carbonate results in the blockage of pores, which impedes further absorption of CO2 into the cement and release of reaction product (water) from the cement.

Carbonation of Portland type concretes is both a good and a bad thing. In reinforced concrete it is not encouraged because as the carbonates form, they also lower the pH of the substrate (Portlandite is consumed). A reduction in pH can cause of the onset of the corrosion of steel reinforcing bars present in the structure.

The concrete used for masonry units is more permeable and carbonates more readily. As the strength of calcite and aragonite, the carbonation products is greater than that of Portlandite, overall strength is improved. As iron rebars are not generally used associated corrosion problems are not an issue.

A fully grouted wall will absorb less than one in which the blocks are unfilled. An average CMU or block, containing 1.4 kg (3 lb) of cement, could absorb .1 Kg (0.8 lb) to 1 lb (0.4-0.5 kg) of CO2 over time

TecEco Cements

TecEco cements include in their formulation a pozzolan, reactive magnesia and a hydraulic cement such as Portland cement. In all formulations the Portlandite released during the curing of the Portland cement component is consumed by the pozzolan to produce more calcium silicate hydrate, a strength giving mineral. In reinforced concretes made using TecEco modified Portland cement formulations, as for ordinary concretes discussed above, carbonation only proceeds to a relatively shallow depth as the formation of magnesium carbonate also results in the blockage of pores, which impedes further absorption of CO2 into the cement and release of reaction product (water) from the cement. The main differences are that the pH of brucite is much lower, reducing alkali silica reaction (ASR) problems but still sufficiently high to maintain the passive oxide layer around rebar deep in the substrate. Durability is improved mainly because of the pore blocking affect as well as lower tendency to carbonate (less negative Gibbs Free energy) and lower solubility of brucite compared to Portlandite (lower concentration of electrolyte).

In masonry products such as mortars and blocks made using TecEco Eco-Cement , there is a much greater proportion of materials such as reactive magnesia (and thus brucite) in the cement component that carbonate and even though carbonation of brucite is slower there are no kinetic barriers and as a result carbonation proceeds to completion and much more CO2 is reabsorbed. A typical Eco-Cement formulation for masonry products would contain 50 - 85% readily carbonated material in the cement component compared to 20-25% in the cement component of ordinary CMU's containing Portland cement only. There is therefore approximately 50 - 75 % more carbonation in an Eco-Cement block compared to an ordinary concrete block.

The Carbonation of TecEco Eco-Cements Vs Other Cements

Material

Approximate Formulae

CO2 Release (Tonnes CO2/Tonne)

CO2 Release (Capture CO2 - Tonnes CO2/Tonne)

CO2 Release after Reabsorbtion (No Capture CO2 - Tonnes CO2/Tonne)

CO2 Release after Reabsorbtion (Capture CO2 - Tonnes CO2/Tonne)

CO2 Release after Reabsorbtion (Capture CO2, Fly and Bottom Ash - Tonnes CO2/Tonne)

Portland cement products

15 mass% Portland cement. 85 mass% aggregate.

.32

N/A

.299

N/A

N/A

Eco-cement products

11.25 mass% reactive magnesia, 3.75 mass% Portland cement. 85 mass% aggregate.

.37

.25

.241

.140

.113

The above table was compiled using a spreadsheet used by TecEco.

The calculations do not take into account the use of sustainable energy to produce Eco-Cements.

Toxic Fumes From Cement Manufacture

The production of cement using natural gas, coal, or fuel oils can cause air pollution problems. Carbon monoxide, sulfur dioxide and particulate matter, and some toxics are produced. Some cement companies also burn a wide variety of hazardous wastes to fire their kilns. This "alternative" production process is controversial because of the possibility of increasing emissions of criteria air pollutants as well as toxic emissions. New contaminants, known as Products of Incomplete Combustion (PICs) are produced during the burning of hazardous wastes in the cement kiln and released into the atmosphere through stack emissions. These products include highly toxic compounds known as dioxins and furans - types of endocrine disruptors -- which are formed when hazardous and other wastes that contain chlorine are burned.

The adoption of TecEco cements will greatly reduce the release of toxic and hazardous materials into the atmosphere.

Phase Change Materials for Eco-Cement Products?

The use of Glauber's salts was studied intensively during the mid-80's in passive solar heating systems and looked like a very promising storage medium. They did not however find wide-spread use.  The advantage of using Glauber's salts is that they have a very high heat capacity and good conductivity which means they hold a lot of heat, and absorb and release it easily. Glauber's salts are phase-change materials.  That is they change state from a solid to liquid as they heat and turn back to a solid as they cool.  The point at which they change phase is when they absorb and release the most heat.  The temperature at which this occurs can be tuned or altered depending on the type and ratio of the additives in the salts.

Other phase change materials used for passive solar heat storage include water and paraffin wax which also have a high heat capacity and high conductivity.  All of these materials have their advantages and disadvantages. Among the advantages are that they absorb and release heat relatively quickly and take up less space than say concrete, masonry or rock.  Disadvantages can be leaks, aesthetics and cost. Eco-cements themselves also have a relatively high thermal capacity and a very high thermal capacity/embodied energy ratio.

TecEco have developed the technology to create bricks, blocks and pavers with a high thermal capacity and very low embodied energy. The incorporation of phase change minerals will improve the ratio of thermal capacity to embodied energy. If any of our readers have technology or knowledge in this area please contact John Harrison our MD.

Erratum

Newsletter 20, Understanding Carbon and Oxygen Cycles, Numbers in the Carbon Cycle

Summary totals presented by the Wood's Hole Institute for carbon in the carbon cycle during the decade ending 1990 (in billion metric tonnes or petograms) are:

Atmospheric increase

=

Emissions from Fossil fuels

+

Net emissions from changes in land use

-

Oceanic uptake

-

Missing carbon sink

3.3(±0.2)

=

5.5(±0.5)

+

1.6(±0.7)

-

2.0(±0.8)

-

1.8(±1.2)

Converting to billion metric tonnes CO2 this is:

Atmospheric increase

=

Emissions from Fossil fuels

 + 

Net emissions from changes in land use

 - 

Oceanic uptake

 - 

Missing carbon sink

12.07 (±0.73)

=

20.152 (±0.1.83)

+

5.86 (±2.56)

-

7.32 (±2.93)

-

6.59 (±4.39)

The figure for annual atmospheric increase in tones CO2 was erroneously previously given as 39.91 billion metric tones CO2

Newsletter 22, Johannesburg - Changing the Paradigm

The Woods Hole estimate of 3.3 billion metric tonnes for the annual atmospheric increases in C (1990) was incorrectly converted to 20 billion tonnes CO2. The correct figure is 12.07 billion tonnes CO2.

The original articles have been corrected for this and other errors

JJ's Column

Tececo's new website is in development. We have re-structured the layout to hopefully make it easier to use and the whole site is being re-written more as a hub for the technology as the global interest grows.

If you have any ideas for the web site please write them down and submit them as soon as possible.

CO2busters (http://www.co2busters.org) is complete and I hope you will join in and make this site a good resource for issues such as global warming, climate change and CO2 abatement.

I am looking forward to the holidays so we can get the new site up and running.

EBN Volume 4, No. 5 -- September/October 1995

For those who our wondering, JJ is John Harrison's 13 year old son (yes JJ's a teenager!) and TecEco's webmaster and information systems manager.