Presentation on theme: "Materials – The Key to Sustainability"— Presentation transcript:
1Materials – The Key to Sustainability TecEco are in the BIGGEST Business on the Planet - Solving Sustainability Problems EconomicallyThe Problem - A Planet in Crisis
2A Demographic Explosion John Harrison Presentation AASMIC ConferenceA Demographic Explosion?Undeveloped CountriesDeveloped CountriesDEMOGRAPHICSGlobal 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.
3Atmospheric Carbon Dioxide John Harrison Presentation AASMIC ConferenceATMOSPHERIC CARBON DIOXIDEOf 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.
4Global Temperature Anomaly John Harrison Presentation AASMIC ConferenceGLOBAL WARMINGThe 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.
5The Carbon Cycle and Emissions Emissions from fossil fuels and cement production are the cause of the global warming problemSource: David Schimel and Lisa Dilling, National Centre for Atmospheric Research 2003
6The 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 systemsMove billion tonnes Use some 50 billion tonnes
7Ecological FootprintOur footprint is exceeding the capacity of the planet to support it. We are not longer sustainable as a species and must change our ways
8There are Detrimental Affects Right Through the Techno-process John Harrison Presentation AASMIC ConferenceThere are Detrimental Affects Right Through the Techno-processDetrimental Linkages that affect earth system flowsTake manipulate and make impactsEnd of lifecycle impactsMaterials are in the Techno-sphere Utility zoneThere is no such place as “away”THERE ARE DETRIMENTAL AFFECTS RIGHT THROUGH THE TECHNO PROCESSMaterials are everything between the take and wasteMaterials are everything between the take and waste and affect earth system flows.Greater UtilityLess Utility
9Materials Affect Underlying Molecular Flows John Harrison Presentation AASMIC ConferenceMaterials Affect Underlying Molecular FlowsTake → Manipulate → Make → Use → Waste[ ←Materials→ ][ ← Underlying molecular flow → ]Damaging to the Environment e.g. heavy metals, cfc’s, c=halogen compounds and CO2Materials 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.
10Innovative 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
11Changing the Techno-process John Harrison Presentation AASMIC ConferenceChanging the Techno-processTake => manipulate => make => use => wasteDriven by fossil fuel energy with detrimental effects on earth systems.Reduce Re-use RecycleEco-innovateINDUSTRIAL ECOLOGY – CHANGING THE TECHNO-PROCESSIndustrial 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 dioxideMaterialsImproving the sustainability of materials used to create the built environment will reduce the impact of the take and waste phases of the techno-process
12Materials & Lifetime & Embodied Energies The embodied energy of materials only contributes 1-2% of the total energy consumed by buildings over their lifetimeIt follows that the properties of materials such as specific heat and conductance are more important to the overall energy consumption and thus emissionsNew materials and materials composites can introduce physical properties that result in them being more sustainable in useIn many instances wastes will provide the physical properties requiredCurrently unheard of paradigms such as materials with high specific heat and low conductance will increase the performance of buildingsAn opportunity will emerge to introduce such composites with the introduction of robotics
13Economically Driven Sustainability John Harrison Presentation AASMIC ConferenceEconomically Driven SustainabilityThe 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 - $Sustainable processes are more efficient and therefore more economic. Natural ecosystems can be 100% efficient. What is needed are new technologies that allow material and energy flows to more closely mimic natural ecosystems.Innovation will deliver these new technical paradigms.ECONOMICALLY DRIVEN SUSTAINABILITYOur approach must not only be holistic, but also economic if we are to have any hope of success.Working for sustainability market forces will make all the difference.The challenge is to move the supply and demand of resources towards more sustainable outcomes by:Stimulating and harnessing human behaviours which underlay economic demand phenomena through cultural change push by governments and other leaders and real improvement in technical and other properties.Delivery of more sustainable technologies by changing the technical paradigm to for example make carbon dioxide and other wastes resources. “By enabling us to make productive use of particular raw materials, technology determines what constitutes a physical resource”(Pilzer, P. Z., 1990).Change is itself a stimulant for economic growth and we therefore have nothing to fear from the process of change towards sustainability.Sustainable processes are more efficient and therefore more economic. What is needed are sustainable process that also deliver sustainable materials and the new TecEco technologies hold much promise of this.Sustainability will not happen by relying on people to do the right thing
14Sustainability = Culture + Technology John Harrison Presentation AASMIC ConferenceSustainability = Culture + TechnologyIncrease in demand/price ratio for sustainability due to educationally induced cultural drift.$SupplyGreater Value/for impact (Sustainability) and economic growthEquilibrium shiftECONOMICSNew Technical Paradigms are required that deliver sustainability.DemandIncrease in supply/price ratio for more sustainable products due to innovative paradigm shifts in technology.#CULTURAL CHANGE AND PARADIGM SHIFTS IN TECHNOLOGYChanges 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
15Changing 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
16A Post – Carbon & Waste Age? John Harrison Presentation AASMIC ConferenceA Post – Carbon & Waste Age?ECO-CEMENTSThe 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 sustainableThe construction industry can be uniquely responsible for helping achieve this transitionWe cannot get there without new technical paradigms.
17BiomimicryThe term biomimicry was popularised by the book of the same name written by Janine BenyusBiomimicry 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.
18Utilizing 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 wastesWe all use carbon and wastes to make our homes! “Biomimicry”
19Re - 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 assimilatedand how we can reduce the impact of these processeswhat energies drive the evolution, devolution and flow of materialsand how we can reduce these energieshow materials impact on lifetime energiesWith the knowledge gained re-design materials to not only be more sustainable but more sustainable in useEnvironmental problems are the result of inherently flawed materials, materials flows and energy systems
20Materials in the Built Environment The built environment is made of materials and is our footprint on earth.It comprises buildings and infrastructure.Building materials comprise70% 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 resourcesCombined in such a manner they cannot easily be separated.Include many toxic elements.
21Huge 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 buildingsMany wastes can contribute to physical properties reducing lifetime energiesCWaste
22Abatement and Sequestration To solve the greenhouse gas problem our approach should be holistically balanced and involveEverybody, every dayBe easyMake moneyNew technical paradigms are requiredSequestrationAbatementand++TecEco-cements = Low emissions production, mineral sequestration + waste utilizationEmissions reduction through efficiency and conversion to non fossil fuelsGeological Seques-trationTecEco’s Contribution
23The TecEco Dream – A More Sustainable Built Environment John Harrison Presentation AASMIC ConferenceThe TecEco Dream – A More Sustainable Built EnvironmentCO2OTHERWASTESCO2 FOR GEOLOGICAL SEQUESTRATIONCO2PERMANENT SEQUESTRATION & WASTE UTILISATION (Man made carbonate rock incorporating wastes as a building material)MININGMgOTECECO KILNMAGNESITE + OTHER INPUTSTECECO CONCRETESRECYCLED BUILDING MATERIALSWe 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 MagazineSUSTAINABLE CITIES
24Impact 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 annumMuch more concrete is used than any other building material.TecEco Pty. Ltd. have benchmark technologies for improvement in sustainability and properties
25Embodied Energy of Building Materials Concrete is relatively environmentally friendly and has a relatively low embodied energyDownloaded from (last accessed 07 March 2000)
26Average 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)
27Emissions from Cement Production Chemical ReleaseThe process of calcination involves driving off chemically bound CO2 with heat.CaCO3 →CaO + ↑CO2Process EnergyMost 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 CO2Arguments 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.
28Cement Production ~= Carbon Dioxide Emissions Between tec, eco and enviro-cements TecEco can provide a viable much more sustainable alternative.
29Portland 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
30Concrete Industry Objectives PCA (USA)Improved energy efficiency of fuels and raw materialsFormulation 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.WBCSDFuels and raw materials efficienciesEmissions reduction during manufacture
31TecEco Technologies Take Concrete into the Future More rapid strength gain even with added pozzolansMore supplementary materials can be used reducing costs and take and waste impacts.Higher strength/binder ratioLess cement can be used reducing costs and take and waste impactsMore durable concretesReducing costs and take and waste impacts.Use of wastesUtilizing carbon dioxideMagnesia component can be made using non fossil fuel energy and CO2 captured during production.Tec -CementsTec & Eco-CementsEco-Cements
32Greening the Largest Material Flow -Concrete Scale down Production.Untenable nonsense, especially to developing nationsUse waste for fuelsNot my area of expertise but questioned by many.Reduce net emissions from manufactureIncrease manufacturing efficiencyIncrease fuel efficiencyWaste stream sequestration using MgO and CaOE.g. Carbonating the Portlandite in waste concreteGiven the current price of carbon in Europe this could be viableTecEco have a mineral sequestration process that is non fossil fuel driven using MgO and the TecEco kilnNot discussed
33Greening ConcreteIncrease the proportion of waste materials that are pozzolanicUsing 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 pozzolansSlow 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 alternativesThere are a number of products with similar properties to Portland cementCarbonating BindersNon-carbonating bindersThe research and development of these binders needs to be accelerated
34Greening Concrete Use aggregates that extend cement Use air as an aggregate making cement go furtherAluminium use questionableFoamed Concretes work well with TecEco eco-cementUse for slabs to improve insulationUse aggregates with lower embodied energy and that result in less emissions or are themselves carbon sinksOther materials that be used to make concrete have lower embodied energies.Local aggregatesRecycled aggregates from building rubbleGlass culletMaterials that non fossil carbon are carbon sinks in concretePlastics, wood etc.Improve the performance of concrete by including aggregates that improve or introduce new properties reducing lifetime energiesWood fibre reduces weight and conductance.
35Waste Stream Sequestration is Part of the TecEco Total Process Serpentine Mg3Si2O5(OH)4Olivine Mg2SiO4This reaction is how most MgCO3 came to be formed anyway so why are we not using it to also sequester carbon?CrushingCrushingCO2 from Power Generation or IndustryGrindingWaste Sulfuric Acid or Alkali?GrindingScreeningSilicate Reactor Process e.g.Mg2SiO4 +2CO2 =>2MgCO3 + SiO2ScreeningMagnetic Sep.Gravity ConcentrationFe, Ni, Co.Heat TreatmentSilicic Acids or SilicaMagnesite (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-KilnCO2 for Geological SequestrationMagnesium Thermodynamic CycleMagnesia (MgO)Magnesite MgCO3)Other Wastes after ProcessingOxide Reactor ProcessCO2 from Power Generation, Industry or CO2 Directly From the AirTonnes 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 TonnesForsterite (Mg Olivine) Billion TonnesTonnes CO2 sequestered by 1 billion tonnes of mineral mined directly.4769.6255Tonnes CO2 captured during calciningTonnes CO2 captured by eco-cementTotal tonnes CO2 sequestered or abated per tonne mineral mined (Single calcination cycle).1.4311.876Total tonnes CO2 sequestered or abated (Five calcination cycles.)3.3394.378Total tonnes CO2 sequestered or abated (Ten calcination cycles).5.7237.506Total tonnes CO2 sequestered or abated (Twenty calcination cycles).11.44615.012MgO for TecEco Cements and Sequestration by Eco-Cements in the Built Environment
36TecEco Technologies Provide a Profitable Solution Silicate → Carbonate Mineral SequestrationUsing 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 TechnologyCombined 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 MgOBeing 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.TecEcoMore Economic under Kyoto?TecEco
37TecEco Kiln Technology John Harrison Presentation AASMIC ConferenceTecEco Kiln TechnologyCan 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 MgOEven 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 kilnCAPTURE OF CO2The 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.
38Increasing the Proportion of Waste Materials that are Pozzolanic AdvantagesLower costsMore durable greener concreteDisadvantagesRate of strength development retardedPotential 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-cementsHigher water demand due to fineness.Finishing is not as easySupported by WBCSD and virtually all industry associationsDriven by legislation and sentiment
39Impact 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 bruciteIncrease 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 demandMore pozzolanic reactionsMg Al hydrates?Improved durability as brucite is much less soluble or reactivePotential long term durability issue due to leaching of Ca from CSH resolved.Improved finishing as Mg++ contributes a strong shear thinning property
40Portlandite Compared to Brucite PropertyPortlandite (Lime)BruciteDensity2.232.9Hardness2.5 – 3Solubility (cold)1.85 g L-1 in H2O at 0 oC0.009 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 oCSolubility (moles, cold)M L-1M L-1Solubility (moles, hot)M L-1M L-1Solubility Product (Ksp)5.5 X 10-61.8 X 10-11ReactivityHighLowFormMassive, sometime fibrousUsually fibrousFree Energy of Formation of Carbonate GofkJ.mol-119.55 kJ.mol-1kJ.mol-1(via hydrate)Cement chemists in the industry should be getting their heads around the differences
41Tec-Cement Concrete Strength Gain Curve We have observed this kind of curve with over 300 cubic meters of concreteThe possibility of high early strength gain with added pozzolans is of great economic and environmental importance.
42Replacement of PC by Carbonating Binders LimeThe most used material next to Portland cement in binders.Generally used on a 1:3 paste basis since Roman timesNon-hydraulic limes set by carbonation and are therefore close to carbon neutral once set.CaO + H2O => Ca(OH)2Ca(OH)2 + CO2 => CaCO3gas ↔ molar volumesVery slight expansion, but shrinkage from loss of water.
43Replacement of PC Carbonating Binders Eco-Cement (TecEco)Have high proportions of reactive magnesium oxideCarbonate like limeGenerally used in a 1:5-1:12 paste basis because much more carbonate “binder” is produced than with limeMgO + H2O <=> Mg(OH)2Mg(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 limeMostly CO2 and water
44Replacement 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 developedHigh belite cementsBeing research by Aberdeen and other universitiesCalcium sulfoaluminate cementsUsed by the Chinese for some timeMagnesium phosphate cementsProponents argue that a lot stronger than Portland cement therefore much less is required.Main disadvantage is that phosphate is a limited resourceGeopolymers
45Geopolymers“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 sustainableUnlikely to be used for pre-mix concrete or waste in the near future because of.process problemsRequiring a degree of skill for implementationnano porosityCausing problems with aggregates in aggressive environmentsno pH control strategy for heavy metals in waste streams
46John Harrison Presentation AASMIC Conference TecEco CementsSUSTAINABILITYDURABILITYSTRENGTHTECECO CEMENTSHydration 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 - POZZOLANMAGNESIATecEco concretes are a system of blending reactive magnesia, Portland cement and usually a pozzolan with other materials and are a key factor for sustainability.
47The Magnesium Thermodynamic Cycle CalcinationCO2 Capture Non fossil fuel energyWe think this cycle is relatively independent of other constituents
48TecEco Cement Technology Theory John Harrison Presentation AASMIC ConferenceTecEco Cement Technology TheoryPortlandite (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 andTecEco add reactive magnesiawhich 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
49John Harrison Presentation AASMIC Conference TecEco FormulationsTec-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.
50TecEco Cements – Impact on Sustainability John Harrison Presentation AASMIC ConferenceTecEco Cements – Impact on SustainabilityThe 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 mixesBoth 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 culletResolving durability issuesSUSTAINABILITY SUMMARYThe Current Technical DirectionReduce the amount of total binder.Use more supplementary materialsPfa, gbfs, industrial pozzolans etc.Use of recycled aggregates.Including aggregates containing carbonThe 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 culletEco-cements further provide carbonation of the binder component.Possibility of easy capture of CO2 during the manufacturing process.
51Benefits 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 energyConcretes containing MgOare demonstrably more durable.can incorporate wastes that contribute to physical properties reducing lifetime energiesIt 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
52TecEco Technologies Take Concrete into the Future More rapid strength gain even with added pozzolansMore supplementary materials can be used reducing costs and take and waste impacts.Higher strength/binder ratioLess cement can be used reducing costs and take and waste impactsMore durable concretesReducing costs and take and waste impacts.Use of wastesUtilizing carbon dioxideMagnesia component can be made using non fossil fuel energy and CO2 captured during production.Tec -CementsTec & Eco-CementsEco-Cements
53Using 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/m3Concretes 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
54Use Aggregates with Lower Embodied Energy and that Result in less Emissions or that are Themselves Carbon SinksUse of aggregates that lower embodied energieswastes such as recycled building rubble tec and eco-cements do not have problems associated with high gypsum contentUse of other aggregates that include non fossil carbonsawdust and other carbon based aggregates can make eco-cement concretes a net carbon sink.Reduce transport embodied energies by using local materials such as earthmud 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
55Improve the Performance of Concrete by Including Aggregates that Improve or Introduce New Properties Reducing Lifetime EnergiesRather 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