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Materials – The Key to Sustainability

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1 Materials – The Key to Sustainability
TecEco are in the BIGGEST Business on the Planet - Solving Sustainability Problems Economically The Problem - A Planet in Crisis

2 A Demographic Explosion
John Harrison Presentation AASMIC Conference A Demographic Explosion ? Undeveloped Countries Developed Countries DEMOGRAPHICS Global population, consumption per capita and our footprint on the planet is exploding. The graph shows population. I wouldn’t like to see a graph of per capita consumption added. The two together would be frightening. The world population passed 6 billion in At the current rate the world will have 7 billion people soon after the year The overwhelming share of world population growth is taking place in developing countries and has more than doubled in 35 years, growing from 1.89 billion in 1955 to 4.13 billion in 1990. Significant proportions of population increases in the developing countries have been and will be absorbed by urban areas which are growing five times faster than urban areas in developed countries. Global population, consumption per capita and our footprint on the planet is exploding.

3 Atmospheric Carbon Dioxide
John Harrison Presentation AASMIC Conference ATMOSPHERIC CARBON DIOXIDE Of particular concern and therefore the most studied is the problem of CO2 in the atmosphere and the global warming that results. The level of CO2 from the burning of fossil fuels is rising too rapidly for natural processes to absorb and in the air has risen from 280 parts per million in pre-industrial times to just under 380 parts per million in 2004.

4 Global Temperature Anomaly
John Harrison Presentation AASMIC Conference GLOBAL WARMING The well documented result of the increase in CO2 in the atmosphere has been global warming and climate change. Simply put, there is ample evidence that increases in consumption per person and population growth have compounded to unsustainable levels.

5 The Carbon Cycle and Emissions
Emissions from fossil fuels and cement production are the cause of the global warming problem Source: David Schimel and Lisa Dilling, National Centre for Atmospheric Research 2003

6 The Techno-Process & Earth Systems
Atmospheric composition, climate, land cover, marine ecosystems, pollution, coastal zones, freshwater systems, salinity and global biological diversity have all been substantially affected. Our linkages to the bio-geo-sphere are defined by the techno process describing and controlling the flow of matter and energy. It is these flows that have detrimental linkages to earth systems. Detrimental affects on earth systems Move billion tonnes Use some 50 billion tonnes

7 Ecological Footprint Our footprint is exceeding the capacity of the planet to support it. We are not longer sustainable as a species and must change our ways

8 There are Detrimental Affects Right Through the Techno-process
John Harrison Presentation AASMIC Conference There are Detrimental Affects Right Through the Techno-process Detrimental Linkages that affect earth system flows Take manipulate and make impacts End of lifecycle impacts Materials are in the Techno-sphere Utility zone There is no such place as “away” THERE ARE DETRIMENTAL AFFECTS RIGHT THROUGH THE TECHNO PROCESS Materials are everything between the take and waste Materials are everything between the take and waste and affect earth system flows. Greater Utility Less Utility

9 Materials Affect Underlying Molecular Flows
John Harrison Presentation AASMIC Conference Materials Affect Underlying Molecular Flows Take → Manipulate → Make → Use → Waste [ ←Materials→ ] [ ← Underlying molecular flow → ] Damaging to the Environment e.g. heavy metals, cfc’s, c=halogen compounds and CO2 Materials influence: How much and what we have to take to manufacture the materials we use. How long materials remain of utility, whether they are easily recycled and how and what form they are in when we eventually throw them “away”. What we take from the environment around us, how we manipulate and make materials out of what we take and what we waste result in underlying molecular flows that affect earth systems.

10 Innovative New Materials - the Key to Sustainability
The choice of materials controls emissions, lifetime and embodied energies, user comfort, use of recycled wastes, durability, recyclability and the properties of wastes returned to the bio-geo-sphere. There is no such place as “away”, only a global commons

11 Changing the Techno-process
John Harrison Presentation AASMIC Conference Changing the Techno-process Take => manipulate => make => use => waste Driven by fossil fuel energy with detrimental effects on earth systems. Reduce Re-use Recycle Eco-innovate INDUSTRIAL ECOLOGY – CHANGING THE TECHNO-PROCESS Industrial ecology, the idea that the waste output of one kind of activity can be resource input for another, is most easily achieved in cities. The materials used determine many properties including weight, embodied energies, fuel related and chemical emissions, lifetime energies, user comfort and health, use of recycled wastes, durability, recyclability and the properties of wastes returned to the bio-geo-sphere. There is huge scope for sequestration and conversion of waste to resource given the massive size of the materials flows involved in the built environment. With the right materials technology, because of its sheer size, the built environment could reduce the take from the bio-geo-sphere and utilise many different wastes including carbon dioxide Materials Improving the sustainability of materials used to create the built environment will reduce the impact of the take and waste phases of the techno-process

12 Materials & Lifetime & Embodied Energies
The embodied energy of materials only contributes 1-2% of the total energy consumed by buildings over their lifetime It follows that the properties of materials such as specific heat and conductance are more important to the overall energy consumption and thus emissions New materials and materials composites can introduce physical properties that result in them being more sustainable in use In many instances wastes will provide the physical properties required Currently unheard of paradigms such as materials with high specific heat and low conductance will increase the performance of buildings An opportunity will emerge to introduce such composites with the introduction of robotics

13 Economically Driven Sustainability
John Harrison Presentation AASMIC Conference Economically Driven Sustainability The challenge is to harness human behaviours which underlay economic supply and demand phenomena by changing the technical paradigm in favour of making carbon dioxide and other wastes resources for new materials with lower take and waste impacts and more energy efficient performance. $ - ECONOMICS - $ Sustainable processes are more efficient and therefore more economic. Natural ecosystems can be 100% efficient. What is needed are new technologies that allow material and energy flows to more closely mimic natural ecosystems. Innovation will deliver these new technical paradigms. ECONOMICALLY DRIVEN SUSTAINABILITY Our approach must not only be holistic, but also economic if we are to have any hope of success. Working for sustainability market forces will make all the difference. The challenge is to move the supply and demand of resources towards more sustainable outcomes by: Stimulating and harnessing human behaviours which underlay economic demand phenomena through cultural change push by governments and other leaders and real improvement in technical and other properties. Delivery of more sustainable technologies by changing the technical paradigm to for example make carbon dioxide and other wastes resources. “By enabling us to make productive use of particular raw materials, technology determines what constitutes a physical resource”(Pilzer, P. Z., 1990). Change is itself a stimulant for economic growth and we therefore have nothing to fear from the process of change towards sustainability. Sustainable processes are more efficient and therefore more economic. What is needed are sustainable process that also deliver sustainable materials and the new TecEco technologies hold much promise of this. Sustainability will not happen by relying on people to do the right thing

14 Sustainability = Culture + Technology
John Harrison Presentation AASMIC Conference Sustainability = Culture + Technology Increase in demand/price ratio for sustainability due to educationally induced cultural drift. $ Supply Greater Value/for impact (Sustainability) and economic growth Equilibrium shift ECONOMICS New Technical Paradigms are required that deliver sustainability. Demand Increase in supply/price ratio for more sustainable products due to innovative paradigm shifts in technology. # CULTURAL CHANGE AND PARADIGM SHIFTS IN TECHNOLOGY Changes in the market interaction of demand and supply reducing energy and resource usage and detrimental linkages with the planet can be achieved through cultural change and innovative changes in the technical paradigm. Sustainability is where Culture and Technology meet Demand Supply

15 Changing the Technology Paradigm
We need materials that require less energy to make them, that last much longer and that contribute properties that reduce lifetime energies. The key is to change the technology paradigm “By enabling us to make productive use of particular raw materials, technology determines what constitutes a physical resource1” Pilzer, Paul Zane, Unlimited Wealth, The Theory and Practice of Economic Alchemy, Crown Publishers Inc. New York.1990

16 A Post – Carbon & Waste Age?
John Harrison Presentation AASMIC Conference A Post – Carbon & Waste Age? ECO-CEMENTS The main magnesium carbonate that form in eco-cement is nesquehonite which is 83 mass % water and CO2 – cheap binder? Lansfordite, another mineral that forms has even more water in it! Magnesium carbonates are generally fibrous and acicular and therefore add microstructural strength. The long term pH is much lower than Portland cement concretes. Combined with the fact that magnesium minerals seem to stick well to other materials the result is that a high proportion of wastes can be included. As mentioned earlier TecEco cements are generally also much more durable. Materials that last longer are much more sustainable The construction industry can be uniquely responsible for helping achieve this transition We cannot get there without new technical paradigms.

17 Biomimicry The term biomimicry was popularised by the book of the same name written by Janine Benyus Biomimicry is a method of solving problems that uses natural processes and systems as a source of knowledge and inspiration. It involves nature as model, measure and mentor. The theory behind biomimicry is that natural processes and systems have evolved over several billion years through a process of research and development commonly referred to as evolution. A reoccurring theme in natural systems is the cyclical flow of matter in such a way that there is no waste of matter or energy.

18 Utilizing Carbon and Wastes (Biomimicry)
During earth's geological history large tonnages of carbon were put away as limestone and other carbonates and as coal and petroleum by the activity of plants and animals. Sequestering carbon in magnesium binders and aggregates in the built environment mimics nature in that carbon is used in the homes or skeletal structures of most plants and animals. In eco-cement blocks and mortars the binder is carbonate and the aggregates are preferably wastes We all use carbon and wastes to make our homes! “Biomimicry”

19 Re - Engineering Materials
To solve environmental problems we need to understand more about materials in relation to the environment. the way their precursors are derived and their degradation products re assimilated and how we can reduce the impact of these processes what energies drive the evolution, devolution and flow of materials and how we can reduce these energies how materials impact on lifetime energies With the knowledge gained re-design materials to not only be more sustainable but more sustainable in use Environmental problems are the result of inherently flawed materials, materials flows and energy systems

20 Materials in the Built Environment
The built environment is made of materials and is our footprint on earth. It comprises buildings and infrastructure. Building materials comprise 70% of materials flows (buildings, infrastructure etc.) 40-50% of waste that goes to landfill (15 % of new materials going to site are wasted.) At 1.5% of world GDP Annual Australian production of building materials likely to be in the order 300 million tonnes or over 15 tonnes per person. Over 20 billion tonnes of building materials are used annually on a world wide basis. Mostly using virgin natural resources Combined in such a manner they cannot easily be separated. Include many toxic elements.

21 Huge Potential for Sustainable Materials
Reducing the impact of the take and waste phases of the techno-process. including carbon in materials they are potentially carbon sinks. including wastes for physical properties as well as chemical composition they become resources. re – engineering materials to reduce the lifetime energy of buildings Many wastes can contribute to physical properties reducing lifetime energies C Waste

22 Abatement and Sequestration
To solve the greenhouse gas problem our approach should be holistically balanced and involve Everybody, every day Be easy Make money New technical paradigms are required Sequestration Abatement and + + TecEco-cements = Low emissions production, mineral sequestration + waste utilization Emissions reduction through efficiency and conversion to non fossil fuels Geological Seques-tration TecEco’s Contribution

23 The TecEco Dream – A More Sustainable Built Environment
John Harrison Presentation AASMIC Conference The TecEco Dream – A More Sustainable Built Environment CO2 OTHERWASTES CO2 FOR GEOLOGICAL SEQUESTRATION CO2 PERMANENT SEQUESTRATION & WASTE UTILISATION (Man made carbonate rock incorporating wastes as a building material) MINING MgO TECECO KILN MAGNESITE + OTHER INPUTS TECECO CONCRETES RECYCLED BUILDING MATERIALS We need materials that require less energy to make them, that last much longer and that contribute properties that reduce lifetime energies “There is a way to make our city streets as green as the Amazon rainforest”. Fred Pearce, New Scientist Magazine SUSTAINABLE CITIES

24 Impact of the Largest Material Flow - Cement and Concrete
Concrete made with cement is the most widely used material on Earth accounting for some 30% of all materials flows on the planet and 70% of all materials flows in the built environment. Global Portland cement production is currently in the order of 2 billion tonnes per annum. Globally over 14 billion tonnes of concrete are poured per year. Over 2 tonnes per person per annum Much more concrete is used than any other building material. TecEco Pty. Ltd. have benchmark technologies for improvement in sustainability and properties

25 Embodied Energy of Building Materials
Concrete is relatively environmentally friendly and has a relatively low embodied energy Downloaded from (last accessed 07 March 2000)

26 Average Embodied Energy in Buildings
Most of the embodied energy in the built environment is in concrete. Because so much concrete is used there is a huge opportunity for sustainability by reducing the embodied energy, reducing the carbon debt (net emissions) and improving properties that reduce lifetime energies. Downloaded from (last accessed 07 March 2000)

27 Emissions from Cement Production
Chemical Release The process of calcination involves driving off chemically bound CO2 with heat. CaCO3 →CaO + ↑CO2 Process Energy Most energy is derived from fossil fuels. Fuel oil, coal and natural gas are directly or indirectly burned to produce the energy required releasing CO2. The production of cement for concretes accounts for around 10% of global anthropogenic CO2. Pearce, F., "The Concrete Jungle Overheats", New Scientist, 19 July, No 2097, 1997 (page 14). CO2 CO2 Arguments that we should reduce cement production relative to other building materials are nonsense because concrete is the most sustainable building material there is. The challenge is to make it more sustainable.

28 Cement Production ~= Carbon Dioxide Emissions
Between tec, eco and enviro-cements TecEco can provide a viable much more sustainable alternative.

29 Portland Cement & Global Warming
Concrete is the third largest contributor to CO2 emissions after the energy and transportation sectors. The cement industry is growing at around 5% a year globally. Mainly China, Thialand and India. On current trends world production of Portland cement will reach 3.5 billion tonnes by a three fold increase on 1990 levels. To achieve Kyoto targets the industry will have to emit less than 1/3 of current emissions per tonne of concrete. Carbon taxes and other legislative changes will provide legislative incentive to change. There is already strong evidence of market incentive to change

30 Concrete Industry Objectives
PCA (USA) Improved energy efficiency of fuels and raw materials Formulation improvements that: Reduce the energy of production and minimize the use of natural resources. Use of crushed limestone and industrial by-products such as fly ash and blast furnace slag. WBCSD Fuels and raw materials efficiencies Emissions reduction during manufacture

31 TecEco Technologies Take Concrete into the Future
More rapid strength gain even with added pozzolans More supplementary materials can be used reducing costs and take and waste impacts. Higher strength/binder ratio Less cement can be used reducing costs and take and waste impacts More durable concretes Reducing costs and take and waste impacts. Use of wastes Utilizing carbon dioxide Magnesia component can be made using non fossil fuel energy and CO2 captured during production. Tec -Cements Tec & Eco-Cements Eco-Cements

32 Greening the Largest Material Flow -Concrete
Scale down Production. Untenable nonsense, especially to developing nations Use waste for fuels Not my area of expertise but questioned by many. Reduce net emissions from manufacture Increase manufacturing efficiency Increase fuel efficiency Waste stream sequestration using MgO and CaO E.g. Carbonating the Portlandite in waste concrete Given the current price of carbon in Europe this could be viable TecEco have a mineral sequestration process that is non fossil fuel driven using MgO and the TecEco kiln Not discussed

33 Greening Concrete Increase the proportion of waste materials that are pozzolanic Using waste pozzolanic materials such as fly ash and slags has the advantage of not only extending cement reducing the embodied energy and net emissions but also of utilizing waste. We could run out of fly ash as coal is phasing out. (e.g. Canada) TecEco technology will allow the use of marginal pozzolans Slow rate of strength development can be increased using TecEco tec-cement technology. Potential long term (50 year plus) durability issues overcome using tec-cement technology. Replace Portland cement with viable alternatives There are a number of products with similar properties to Portland cement Carbonating Binders Non-carbonating binders The research and development of these binders needs to be accelerated

34 Greening Concrete Use aggregates that extend cement
Use air as an aggregate making cement go further Aluminium use questionable Foamed Concretes work well with TecEco eco-cement Use for slabs to improve insulation Use aggregates with lower embodied energy and that result in less emissions or are themselves carbon sinks Other materials that be used to make concrete have lower embodied energies. Local aggregates Recycled aggregates from building rubble Glass cullet Materials that non fossil carbon are carbon sinks in concrete Plastics, wood etc. Improve the performance of concrete by including aggregates that improve or introduce new properties reducing lifetime energies Wood fibre reduces weight and conductance.

35 Waste Stream Sequestration is Part of the TecEco Total Process
Serpentine Mg3Si2O5(OH)4 Olivine Mg2SiO4 This reaction is how most MgCO3 came to be formed anyway so why are we not using it to also sequester carbon? Crushing Crushing CO2 from Power Generation or Industry Grinding Waste Sulfuric Acid or Alkali? Grinding Screening Silicate Reactor Process e.g. Mg2SiO4 +2CO2 =>2MgCO3 + SiO2 Screening Magnetic Sep. Gravity Concentration Fe, Ni, Co. Heat Treatment Silicic Acids or Silica Magnesite (MgCO3) Simplified TecEco Reactions Tec-Kiln MgCO3 → MgO + CO kJ/mole Reactor Process MgO + CO2 → MgCO kJ/mole (usually more complex hydrates) Solar or Wind Electricity Powered Tec-Kiln CO2 for Geological Sequestration Magnesium Thermodynamic Cycle Magnesia (MgO) Magnesite MgCO3) Other Wastes after Processing Oxide Reactor Process CO2 from Power Generation, Industry or CO2 Directly From the Air Tonnes CO2 Sequestered per Tonne Silicate with Various Cycles through the TecEco Process (assuming no leakage MgO to built environment i.e complete cycles) Chrysotile (Serpentinite) Billion Tonnes Forsterite (Mg Olivine) Billion Tonnes Tonnes CO2 sequestered by 1 billion tonnes of mineral mined directly .4769 .6255 Tonnes CO2 captured during calcining Tonnes CO2 captured by eco-cement Total tonnes CO2 sequestered or abated per tonne mineral mined (Single calcination cycle). 1.431 1.876 Total tonnes CO2 sequestered or abated (Five calcination cycles.) 3.339 4.378 Total tonnes CO2 sequestered or abated (Ten calcination cycles). 5.723 7.506 Total tonnes CO2 sequestered or abated (Twenty calcination cycles). 11.446 15.012 MgO for TecEco Cements and Sequestration by Eco-Cements in the Built Environment

36 TecEco Technologies Provide a Profitable Solution
Silicate → Carbonate Mineral Sequestration Using either peridotite, forsterite or serpentine as inputs to a silicate reactor process CO2 is sequestered and magnesite produced. Proven by others (NETL,MIT,TNO, Finnish govt. etc.) Tec-Kiln Technology Combined calcining and grinding in a closed system allowing the capture of CO2. Powered by waste heat, solar or solar derived energy. To be proved but simple and should work! Direct Scrubbing of CO2 using MgO Being proven by others (NETL,MIT,TNO, Finnish govt. etc.) Tec and Eco-Cement Concretes in the Built Environment. TecEco eco-cements set by absorbing CO2 and are as good as proven. TecEco More Economic under Kyoto? TecEco

37 TecEco Kiln Technology
John Harrison Presentation AASMIC Conference TecEco Kiln Technology Can run at low temperatures. Can be powered by variable non fossil fuel energy. Runs 25% to 30% more efficiency. Theoretically capable of producing much more reactive MgO Even with ores of high Fe content. Captures CO2 for bottling and sale to the oil industry (geological sequestration). Grinds and calcines at the same time. Part of a major process to solve global CO2 problems. Will result in new markets for ultra reactive low lattice energy MgO (e.g. cement, paper and environment industries) TecEco need your backing to develop the kiln CAPTURE OF CO2 The capture of CO2 at source during the manufacturing process is easier for the calcination of magnesium carbonates than any other carbonate mainly because the process occurs at relatively low temperatures. TecEco Pty. Ltd. own intellectual property in relation to a new tec-kiln in which grinding and calcining can occur at the same time in the same vessel for higher efficiencies and easy capture of CO2. Provided sufficient uses can be found for pure CO2 produced during manufacture whereby it is also permanently sequestered, a system for sequestration on a massive scale using carbonates as building materials is very promising. Possibilities for alternative permanent disposal are in materials such as plastics or deep underground where CO2 reacts with country rock forming more carbonate.

38 Increasing the Proportion of Waste Materials that are Pozzolanic
Advantages Lower costs More durable greener concrete Disadvantages Rate of strength development retarded Potential long term durability issue due to leaching of Ca from CSH. Glasser and others have observed leaching of Ca from CSH and this will eventually cause long term unpredictable behavior of CSH. Resolved by presence of brucite in tec-cements Higher water demand due to fineness. Finishing is not as easy Supported by WBCSD and virtually all industry associations Driven by legislation and sentiment

39 Impact of TecEco Tec-Cement Technology on the use of Pozzolans
In TecEco tec-cements Portlandite is generally consumed by the pozzolanic reaction and replaced with brucite Increase in rate of strength development particularly in the first 3-4 days. Internal consumption of water by MgO as it hydrates reducing impact of fineness demand More pozzolanic reactions Mg Al hydrates? Improved durability as brucite is much less soluble or reactive Potential long term durability issue due to leaching of Ca from CSH resolved. Improved finishing as Mg++ contributes a strong shear thinning property

40 Portlandite Compared to Brucite
Property Portlandite (Lime) Brucite Density 2.23 2.9 Hardness 2.5 – 3 Solubility (cold) 1.85 g L-1 in H2O at 0 oC 0.009 g L-1 in H2O at 18 oC. Solubility (hot) .77 g L-1 in H2O at 100 oC .004 g L-1 H2O at 100 oC Solubility (moles, cold) M L-1 M L-1 Solubility (moles, hot) M L-1 M L-1 Solubility Product (Ksp) 5.5 X 10-6 1.8 X 10-11 Reactivity High Low Form Massive, sometime fibrous Usually fibrous Free Energy of Formation of Carbonate Gof kJ.mol-1 19.55 kJ.mol-1 kJ.mol-1(via hydrate) Cement chemists in the industry should be getting their heads around the differences

41 Tec-Cement Concrete Strength Gain Curve
We have observed this kind of curve with over 300 cubic meters of concrete The possibility of high early strength gain with added pozzolans is of great economic and environmental importance.

42 Replacement of PC by Carbonating Binders
Lime The most used material next to Portland cement in binders. Generally used on a 1:3 paste basis since Roman times Non-hydraulic limes set by carbonation and are therefore close to carbon neutral once set. CaO + H2O => Ca(OH)2 Ca(OH)2 + CO2 => CaCO3 gas ↔ molar volumes Very slight expansion, but shrinkage from loss of water.

43 Replacement of PC Carbonating Binders
Eco-Cement (TecEco) Have high proportions of reactive magnesium oxide Carbonate like lime Generally used in a 1:5-1:12 paste basis because much more carbonate “binder” is produced than with lime MgO + H2O <=> Mg(OH)2 Mg(OH)2 + CO2 + H2O <=> MgCO3.3H2O <=> molar mass (at least!) gas <=> molar volumes (at least!) 307 % expansion (less water volume reduction) producing much more binder per mole of MgO than lime (around 8 times) Carbonates tend to be fibrous adding significant micro structural strength compared to lime Mostly CO2 and water

44 Replacement with Non Carbonating Binders
There are a number of other novel cements with intrinsically lower energy requirements and CO2 emissions than conventional Portland cements that have been developed High belite cements Being research by Aberdeen and other universities Calcium sulfoaluminate cements Used by the Chinese for some time Magnesium phosphate cements Proponents argue that a lot stronger than Portland cement therefore much less is required. Main disadvantage is that phosphate is a limited resource Geopolymers

45 Geopolymers “Geopolymers” consists of SiO4 and AlO4 tetrahedra linked alternately by sharing all the oxygens. Positive ions (Na+, K+, Li+, Ca++, Ba++, NH4+, H3O+) must be present in the framework cavities to balance the negative charge of Al3+ in IV fold coordination. Theoretically very sustainable Unlikely to be used for pre-mix concrete or waste in the near future because of. process problems Requiring a degree of skill for implementation nano porosity Causing problems with aggregates in aggressive environments no pH control strategy for heavy metals in waste streams

46 John Harrison Presentation AASMIC Conference
TecEco Cements SUSTAINABILITY DURABILITY STRENGTH TECECO CEMENTS Hydration of the various components of Portland cement for strength. Reaction of alkali with pozzolans (e.g. lime with fly ash.) for sustainability, durability and strength. Hydration of magnesia => brucite for strength, workability, dimensional stability and durability. In Eco-cements carbonation of brucite => nesquehonite, lansfordite and an amorphous phase for sustainability. PORTLAND + or - POZZOLAN MAGNESIA TecEco concretes are a system of blending reactive magnesia, Portland cement and usually a pozzolan with other materials and are a key factor for sustainability.

47 The Magnesium Thermodynamic Cycle
Calcination CO2 Capture Non fossil fuel energy We think this cycle is relatively independent of other constituents

48 TecEco Cement Technology Theory
John Harrison Presentation AASMIC Conference TecEco Cement Technology Theory Portlandite (Ca(OH)2) is too soluble, mobile and reactive. It carbonates, reacts with Cl- and SO4- and being soluble can act as an electrolyte. TecEco generally (but not always) remove Portlandite using the pozzolanic reaction and TecEco add reactive magnesia which hydrates, consuming water and concentrating alkalis forming brucite which is another alkali, but much less soluble, mobile or reactive than Portlandite. In Eco-cements brucite carbonates

49 John Harrison Presentation AASMIC Conference
TecEco Formulations Tec-cements (Low MgO) contain more Portland cement than reactive magnesia. Reactive magnesia hydrates in the same rate order as Portland cement forming Brucite which uses up water reducing the voids:paste ratio, increasing density and possibly raising the short term pH. Reactions with pozzolans are more affective. After all the Portlandite has been consumed Brucite controls the long term pH which is lower and due to it’s low solubility, mobility and reactivity results in greater durability. Other benefits include improvements in density, strength and rheology, reduced permeability and shrinkage and the use of a wider range of aggregates many of which are potentially wastes without reaction problems. Eco-cements (High MgO) contain more reactive magnesia than in tec-cements. Brucite in porous materials carbonates forming stronger fibrous mineral carbonates and therefore presenting huge opportunities for waste utilisation and sequestration. Enviro-cements (High MgO) contain similar ratios of MgO and OPC to eco-cements but in non porous concretes brucite does not carbonate readily. Higher proportions of magnesia are most suited to toxic and hazardous waste immobilisation and when durability is required. Strength is not developed quickly nor to the same extent.

50 TecEco Cements – Impact on Sustainability
John Harrison Presentation AASMIC Conference TecEco Cements – Impact on Sustainability The CO2 released by calcined carbonates used to make binders can be captured using TecEco kiln technology. Tec-Cements Develop Significant Early Strength even with Added Supplementary Materials. Around % less total binder is required for the same strength. Eco-cements carbonate sequestering CO2 requiring 25-75% less binder in some mixes Both tec and eco=cements provide a benign low pH environment for hosting large quantities of waste overcoming problems of: Using acids to etch plastics so they bond with concretes. sulphates from plasterboard etc. ending up in recycled construction materials. heavy metals and other contaminants. delayed reactivity e.g. ASR with glass cullet Resolving durability issues SUSTAINABILITY SUMMARY The Current Technical Direction Reduce the amount of total binder. Use more supplementary materials Pfa, gbfs, industrial pozzolans etc. Use of recycled aggregates. Including aggregates containing carbon The use of MgO potentially overcomes: Problems using acids to etch plastics so they bond with concretes. Problem of sulphates from plasterboard etc. ending up in recycled construction materials. Problems with heavy metals and other contaminants. Problems with delayed reactivity e.g. ASR with glass cullet Eco-cements further provide carbonation of the binder component. Possibility of easy capture of CO2 during the manufacturing process.

51 Benefits to the Concrete Industry of Adopting TecEco Technology
Utilizing wastes to make concretes. Tec-cements have more rapid strength development with fly ash, bottom ash, industrial slags etc. (Tec-Cements.) Reducing energy and emissions during the production of cements. MgO can be made using non fossil fuel energy Concretes containing MgO are demonstrably more durable. can incorporate wastes that contribute to physical properties reducing lifetime energies It makes sense to sequester carbon by allowing MgO to re-carbonate and thereby gain strength. The biggest business on the planet is going to be the sustainability business

52 TecEco Technologies Take Concrete into the Future
More rapid strength gain even with added pozzolans More supplementary materials can be used reducing costs and take and waste impacts. Higher strength/binder ratio Less cement can be used reducing costs and take and waste impacts More durable concretes Reducing costs and take and waste impacts. Use of wastes Utilizing carbon dioxide Magnesia component can be made using non fossil fuel energy and CO2 captured during production. Tec -Cements Tec & Eco-Cements Eco-Cements

53 Using Aggregates that Extend Cement
Air used in foamed concrete is a cheap low embodied energy aggregate and has the advantage of reducing the conductance of concrete. Concrete, depending on aggregates weighs in the order of 2350 Kg/m3 Concretes of over 10 mp as light as 1000 Kg/m3 can be achieved. At 1500 Kg/m3 25 mpa easily achieved. From our experiments so far with Buildlite Cellular Concrete PL tec-cement formulations increase strength performance by around 5-10% for the same mass. Claimed use of aluminium and autoclaving to make more sustainable blocks questionable

54 Use Aggregates with Lower Embodied Energy and that Result in less Emissions or that are Themselves Carbon Sinks Use of aggregates that lower embodied energies wastes such as recycled building rubble tec and eco-cements do not have problems associated with high gypsum content Use of other aggregates that include non fossil carbon sawdust and other carbon based aggregates can make eco-cement concretes a net carbon sink. Reduce transport embodied energies by using local materials such as earth mud bricks and adobe. our research in the UK and with mud bricks in Australia indicate that eco-cement formulations seem to work much better than PC for this

55 Improve the Performance of Concrete by Including Aggregates that Improve or Introduce New Properties Reducing Lifetime Energies Rather than be taken to landfill many wastes can be used to improve properties of concrete that reduce lifetime energies. For example paper and plastic have in common reasonable tensile strength, low mass and low conductance and can be used to make cementitious composites that assume these properties


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