Presentation on theme: "Greening Mineral Binders"— Presentation transcript:
1Greening Mineral Binders John Harrison Presentation AASMIC ConferenceGreening Mineral BindersThe technology paradigm defines what is or is not a resource - PillzerPresentation by John Harrison, managing director of TecEco and inventor of Tec and Eco-Cements and the CarbonSafe process.Our slides are deliberately verbose as most people download and view them from the net. Because of time constraints I will have to race over some slides John Harrison B.Sc. B.Ec. FCPA.
2Under Materials Flows in the Techno-Processes are Molecular Flows John Harrison Presentation AASMIC ConferenceUnder Materials Flows in the Techno-Processes are Molecular FlowsTake → Manipulate → Make → Use → Waste[ ←Materials→ ][ ← Underlying molecular flow → ]If the underlying molecular flows are “out of tune” with nature there is damage to the environment e.g. heavy metals, cfc’s, c=halogen compounds and CO2Moleconomics Is the study of the form of atoms in molecules, their flow, interactions, balances, stocks and positions. 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. These flows should mimic or minimally interfere with natural flows.MOLECONOMIC FLOWSUnderlying the flow of materials through the techno process is a moleconomic flow of molecules that is out of tune with the rest of the planet and causing damage to the environment. If you want to know more about the science of moleconomics please go to our web site and look under projects.
3Abatement and Sequestration To solve sustainability problems our approach should be holistically balanced and involveEverybody, every dayBe easyMake moneyAbatementSequestrationandNew technical paradigms are required+CarbonSafe = Sequestration and waste utilisation.Abatement = Efficiency and conversion to non fossil fuelsTecEco’s Contribution
4The TecEco CarbonSafe Geo-Photosynthethic Process John Harrison Presentation AASMIC ConferenceThe TecEco CarbonSafe Geo-Photosynthethic ProcessThe CarbonSafe Geo-Photosynthetic Process is TecEco’s evolving techno-process that delivers profitable outcomes whilst reversing underlying undesirable moleconomic flows from other less sustainable processes.Inputs:Atmospheric or smokestack CO2, brines, waste acid, other wastesOutputs:Potable water, gypsum, sodium bicarbonate, salts, building materials, bottled concentrated CO2 (for geo-sequestration and other uses).Solar or solar derived energyCO2CO2CO2TecEco KilnTecEco MgCO2 CycleCO2MgOMgCO3Greensols Process1.29 gm/l MgCoalCarbon or carbon compounds Magnesium oxideFossil fuelsOilCO2
5The TecEco CarbonSafe Industrial Ecology John Harrison Presentation AASMIC ConferenceThe TecEco CarbonSafe Industrial EcologyInputs Brines Waste Acid CO2CARBONSAFE VECTORSThe CarbonSafe process starts with either magnesium silicates or the Greensols process. In the case of silicates, magnesium carbonates are produced using proven mineral sequestration technology and then transferred to the MgCO3 cycle. The Greensols process on the other hand uses carbon dioxide from power stations and waste acid to extract magnesium carbonate and other salts from seawater or suitable brines and produces potable water as a by-product. The MgCO3 from either process is then calcined in the TecEco kiln which removes and captures carbon dioxide, ready for incorporation for example into cellulose or fuel made by genetically engineered blue green algae, and produces magnesium oxide. This magnesium oxide can either be used to make TecEco cements which in the case of eco-cement absorb more atmospheric CO2 as they harden or alternatively be used to sequester more CO2 in a hydroxide/carbonate slurry capture process.The MgCO3 produced by the hydroxide slurry process can be decarbonated and cycle around that process indefinitely as in this slide.Outputs Gypsum, Sodium bicarbonate, Salts, Building materials, Potable waterWe must design whole new technical paradigms that reverse many of our problem molecular flows
6The CarbonSafe Geo-Photosynthetic Process John Harrison Presentation AASMIC ConferenceThe CarbonSafe Geo-Photosynthetic Process1.354 x 109 km3 Seawater containing tonne Mg or suitable brines from other sourcesSeawater Carbonation ProcessWaste AcidGypsum + carbon waste (e.g. sewerage) = fertilizersBicarbonate of Soda (NaHCO3)CO2 from power generation or industryOther salts Na+,K+, Ca2+,Cl-Gypsum (CaSO4)Sewerage compostCO2 as a biological or industrial input or if no other use geological sequestrationMagnesite (MgCO3)Solar Process to Produce Magnesium MetalMagnesium Thermodynamic CycleSimplified TecEco Reactions Tec-Kiln MgCO3 → MgO + CO kJ/mole Reactor Process MgO + CO2 → MgCO kJ/mole (usually more complex hydrates)Magnesite (MgCO3)CO2 from power generation, industry or out of the airMagnesia (MgO)Hydroxide Reactor ProcessSequestration Table – Mg from SeawaterCO2Eco-Cement Tec-CementTonnes CO2 sequestered per tonne magnesium with various cycles through the TecEco Tec-Kiln process. Assuming no leakage MgO to built environment (i.e. complete cycles).Billion TonnesTonnes CO2 sequestered by 1 billion tonnes of Mg in seawaterTonnes CO2 captured during calcining (same as above)Tonnes CO2 captured by eco-cementTotal tonnes CO2 sequestered or abated per tonne Mg in seawater (Single calcination cycle).Total tonnes CO2 sequestered or abated (Five calcination cycles.)Total tonnes CO2 sequestered or abated (Ten calcination cycles).36.20Other Wastes
7TecEco CO2 Capture Kiln Technology John Harrison Presentation AASMIC ConferenceTecEco CO2 Capture Kiln TechnologyCan run at low temperatures.Can be powered by various non fossil fuels.E.g. solarTheoretically 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.Runs 25% to 30% more efficiently as use waste heat from grindingWill result in new markets for ultra reactive low lattice energy MgO (e.g. cement, paper and environment industries)CAPTURE 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.
8Re - Engineering Materials – What we Build With 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
9Huge 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 energiesCCO2Waste
10Utilizing 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”
11Impact 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 2.2 billion tonnes per annum.Globally over 15 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
12Embodied Energy of Building Materials Concrete is relatively environmentally friendly and has a relatively low embodied energyDownloaded from (last accessed 07 March 2000)
13Average 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)
14Emissions 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.
15Cement Production ~= Carbon Dioxide Emissions Between Tec, Eco and Enviro-Cements TecEco can provide a viable much more sustainable alternative.
16The 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
17A Low Energy Post – Carbon & Waste Age? John Harrison Presentation AASMIC ConferenceA Low Energy 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 transitionMaybe then we can move confidently into a more sustainable future.
18Concrete 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.WBCSDFuels and raw materials efficienciesEmissions reduction during manufacture
19Greening 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
20Greening 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.TecEco technology will allow the use of marginal pozzolansSlow rate of strength development increased in first few hours and daysPotential long term (50 year plus) durability issues overcome using tec-cement technologyFinishing problems overcomeWe could run out of fly ash as coal is phasing out. (e.g. Canada)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
21Greening Concrete Use aggregates that extend cement Use air as an aggregate making cement go furtherFoamed Concretes work well with TecEco cementsUse for slabs to improve insulationAluminium use questionableUse 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 low impact aggregatesWaste materialsRecycled 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.
224. Increasing 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.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
23Impact 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 in the first 3-4 days.Internal consumption of water by MgO as it hydrates reducing impact of fineness demandMore pozzolanic reactionsMg Al hydrates?Followed by straight line developmentImproved durability as brucite is much less soluble or reactivePotential long term durability issue due to leaching of Ca from CSH resolved.Influence of kosmotopic Mg++Concretes easier to finish with a strong shear thinning propertyGel up more quickly – so finishers can go home earlier even with added pozzolanEarly strength development in the first few days – previously a problem with added pozzolanLess shrinkage and cracking
24Portlandite 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
25Tec-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.
265.a Replacement 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.
275.a Replacement 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
285.b 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 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
29Geopolymers“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
30John 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.
31The Magnesium Thermodynamic Cycle CalcinationCO2 Capture Non fossil fuel energyWe think this cycle is relatively independent of other constituents
32TecEco 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
33John 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.
34TecEco 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.MgO can be made using non fossil fuel energyTec-Cements Develop Significant Early Strength even with Added Supplementary Materials.Eco-Cements carbonate sequestering CO2 requiring 25-75% less binder in some mixesSUSTAINABILITY 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.
35Benefits to the Concrete Industry of Adopting TecEco Technology Both Tec and Eco-Cements provide a benign low pH environment for hosting large quantities of waste overcoming problems of delayed reactions: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 issuesIndian and Chinese quality control issuesConcretes containing MgOshrink lessare demonstrably more durable.can incorporate wastes that contribute to physical properties reducing lifetime energiesThe biggest business on the planet is going to be the sustainability business
366. 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/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 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
377. Use 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 better than PC for this
38John Harrison Presentation AASMIC Conference Using Wastes and Non-Traditional Aggregates to Make TecEco Cement ConcretesAs the price of fuel rises, the use of local or on site low embodied energy materials rather than carted aggregates will have to be considered.No longer an option?The use of on site and local wastes will be made possible by the use of low reactivity TecEco mixes and a better understanding of particle packing. We hope with our new software to be able to demonstrate how adding specific size ranges can make an unusable waste such as a tailing or sludge suitable for making cementitious materials.DUE TO RISING FUEL PRICES WE WILL HAVE TO RECONSIDER USING LOCAL MATERIALSThe use of on site and local wastes will be made possible by the use of low reactivity TecEco mixes and a better understanding of particle packing. We hope with our new software to be able to demonstrate how adding specific size ranges can make an unusable waste such as a tailing or sludge suitable for making cementitious materials.Recent natural disasters such as the recent tsunami and Pakistani earthquake mean we urgently need to commercialize technologies like TecEco’s because they provide benign environments allowing the use of many local materials and wastes without delayed reactions
398. Improve 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
40Biomimicry - Ultimate Recyclers John Harrison Presentation AASMIC ConferenceBiomimicry - Ultimate RecyclersAs peak oil looms and the price of transport is set to rise sharplyWe should not just be recycling based on chemical property requiring sophisticated equipment and resourcesWe should be including wastes based on physical properties as well as chemical composition in composites whereby they become local resources.The Jackdaw recycles all sorts of things it finds nearby based on physical property.The bird is not concerned about chemical composition and the nest it makes could be described as a composite material.TecEco cements are benign binders that can incorporate all sort of wastes without reaction problems. We can do the same as the Jackdoor
41TecEco 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.Easier to finish even with added pozzolansThe stickiness concretes with added fly ash is retarding useHigher 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-CementsContact:John Harrison, TecEco Pty. Ltd.
42John Harrison Presentation AASMIC Conference Eco-CementsEco-cements are similar but potentially superior to lime mortars because:The calcination phase of the magnesium thermodynamic cycle takes place at a much lower temperature and is therefore more efficient.Magnesium minerals are generally more fibrous and acicular than calcium minerals and hence add microstructural strength.Water forms part of the binder minerals that forming making the cement component go further. In terms of binder produced for starting material in cement, eco-cements are much more efficient.Magnesium hydroxide in particular and to some extent the carbonates are less reactive and mobile and thus much more durable.ECO-CEMENTS COMPARED TO CARBONATING LIME MORTARSThe underlying chemistry is very similar however eco-cements are potentially superior to lime mortars because:The calcination phase of the magnesium thermodynamic cycle takes place at a much lower temperatureMagnesium minerals are generally more fibrous and acicular than calcium minerals and hence a lot stronger.Water forms part of the binder minerals that forming making the cement component go further.Magnesium hydroxide in particular and to some extent the carbonates are less reactive and mobile and thus much more durable.A less reactive environment with a lower long term pH. (around 10.5 instead of 12.35)Because magnesium has a low molecular weight, proportionally a much greater amount of CO2 is captured.
43Eco-Cement Strength Development Eco-cements gain early strength from the hydration of PC.Later strength comes from the carbonation of brucite forming an amorphous phase, lansfordite and nesquehonite.Strength gain in eco-cements is mainly microstructural because ofMore ideal particle packing (Brucite particles at 4-5 micron are under half the size of cement grains.)The natural fibrous and acicular shape of magnesium carbonate minerals which tend to lock together.More binder is formed than with calciumTotal volumetric expansion from magnesium oxide to lansfordite is for example volume 811%.Mg(OH)2 + CO2 MgCO3.5H2OFrom air and water
44Eco-Cement Strength Gain Curve Eco-cement bricks, blocks, pavers and mortars etc. take a while to come to the same or greater strength than OPC formulations but are stronger than lime based formulations.
45Chemistry of Eco-Cements There are a number of carbonates of magnesium. The main ones appear to be an amorphous phase, lansfordite and nesquehonite.The carbonation of magnesium hydroxide does not proceed as readily as that of calcium hydroxide.Gor Brucite to nesquehonite = kJ.mol-1Compare to Gor Portlandite to calcite = kJ.mol-1The dehydration of nesquehonite to form magnesite is not favoured by simple thermodynamics but may occur in the long term under the right conditions.Gor nesquehonite to magnesite = 8.56 kJ.mol-1But kinetically driven by desiccation during drying.Reactive magnesia can carbonate in dry conditions – so keep bags sealed!For a full discussion of the thermodynamics see our technical documents.TecEco technical documents on the web cover the important aspects of carbonation.
48CarbonationEco-cement is based on blending reactive magnesium oxide with other hydraulic cements and then allowing the Brucite and Portlandite components to carbonate in porous materials such as concretes blocks and mortars.Magnesium is a small lightweight atom and the carbonates that form contain proportionally a lot of CO2 and water and are stronger because of superior microstructure.The use of eco-cements for block manufacture, particularly in conjunction with the kiln also invented by TecEco (The Tec-Kiln) would result in sequestration on a massive scale.As Fred Pearce reported in New Scientist Magazine (Pearce, F., 2002), “There is a way to make our city streets as green as the Amazon rainforest”.Ancient and modern carbonating lime mortars are based on this principle
49Aggregate Requirements for Carbonation The requirements for totally hydraulic limes and all hydraulic concretes is to minimise the amount of water for hydraulic strength and maximise compaction and for this purpose aggregates that require grading and relatively fine rounded sands to minimise voids are requiredFor carbonating eco-cements and lime mortars on the on the hand the matrix must “breathe” i.e. they must be porousRequiring relative mono grading so that particle packing is imperfect causing physical air voids and some vapour permeability.
50CO2 Abatement in Eco-Cements John Harrison Presentation AASMIC ConferenceCO2 Abatement in Eco-CementsFor 85 wt% Aggregates15 wt% CementPortland Cements 15 mass% Portland cement, 85 mass% aggregateEmissions .32 tonnes to the tonne. After carbonation. Approximately .299 tonne to the tonne.No Capture 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate.Emissions .37 tonnes to the tonne. After carbonation. approximately .241 tonne to the tonne.Capture CO % mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate.Emissions .25 tonnes to the tonne. After carbonation. approximately tonne to the tonne.Capture CO2. Fly and Bottom Ash 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate.Emissions .126 tonnes to the tonne. After carbonation. Approximately .113 tonne to the tonne.Eco-cements in porous products absorb carbon dioxide from the atmosphere. Brucite carbonates forming lansfordite, nesquehonite and an amorphous phase, completing the thermodynamic cycle.Greater SustainabilityCO2 ABATEMENT IN AN ECO-CEMENT BLOCKThe above slide shows that for an eco-cement concrete in a block which is 15% eco-cement if the eco-cement contains 75% reactive magnesia and with capture of CO2 during the manufacturing process and the use of a pozzolan after carbonation net emissions are less than a third as much..299 > .241 >.140 >.113 Bricks, blocks, pavers, mortars and pavement made using eco-cement, fly and bottom ash (with capture of CO2 during manufacture of reactive magnesia) have 2.65 times less emissions than if they were made with Portland cement.
51John Harrison Presentation AASMIC Conference TecEco Cement LCATecEco Concretes will have a big role post Kyoto as they offer potential sequestration as well as waste utilisationTECECO LCA MODELFor more information on the contribution our Tec and Eco-Cements can make to the global carbon balance please consult our LCA model under tools on the web site.The TecEco LCA model is available for download under “tools” on the web site
52Tec-Cement Concretes - Lattice Energy Destroys a Myth John Harrison Presentation AASMIC ConferenceTec-Cement Concretes - Lattice Energy Destroys a MythMagnesia, provided it is reactive rather than “dead burned” (or high density, crystalline periclase type), can be beneficially added to cements in excess of the amount of 5 mass% generally considered as the maximum allowable by standards prevalent in concrete dogma.Reactive magnesia is essentially amorphous magnesia with low lattice energy.It is produced at low temperatures and finely ground, andwill completely hydrate in the same time order as the minerals contained in most hydraulic cements.Dead burned magnesia and lime have high lattice energiesCrystalline magnesium oxide or periclase has a calculated lattice energy of 3795 Kj mol-1 which must be overcome for it to go into solution or for reaction to occur.Dead burned magnesia is much less expansive than dead burned lime in a hydraulic binder (Ramachandran V. S., Concrete Science, Heydon & Son Ltd. 1981, p )
53More Rapid Early Strength Development Concretes are more often than not made to strength.The use of tec-cement results inmore rapid early strength development even with added pozzolans.Straight line strength development for a long timeEarly strength gain with less cement and added pozzolans is of great economic and environmental importance as it will allow the use of more pozzolans.We have observed this sort of curve in over 500 cubic meters of concrete now
54Reasons for Compressive Strength Development in Tec-Cements. John Harrison Presentation AASMIC ConferenceReasons for Compressive Strength Development in Tec-Cements.Kosmotropic nature of Mg++Reactive magnesia requires considerable water to hydrate resulting in:Denser, less permeable concrete. Self compaction?A significantly lower voids/paste ratio.Higher early pH initiating more effective silicification reactions?The Ca(OH)2 normally lost in bleed water is used internally for reaction with pozzolans.Super saturation of alkalis caused by the removal of water?Micro-structural strength due to particle packing (Magnesia particles at 4-5 micron are a little over ½ the size of cement grains.)Formation of MgAl hydrates? Similar to flash set in concrete but slower??Formation of MSH??Slow release of water from hydrated Mg(OH)2.nH2O supplying H2O for more complete hydration of C2S and C3S?Brucite gains weight in excess of the theoretical increase due to MgO conversion to Mg(OH)2 in samples cured at 98% RH.Dr Luc Vandepierre, Cambridge University, 20 September, 2005.
55Greater Tensile Strength ++++++++Cement++MgO+Sand+++++++++Mutual RepulsionPh 12 ?=>Mutual Repulsion+++-+-+++Cement+-MgO-Sand+--+++-++Mutual AttractionMgO Changes Surface Charge as the Ph Rises. This could be one of the reasons for rapid gelling and greater tensile strength displayed during the early plastic phase of tec-cement concretes. The affect of additives is not yet known
56Non Newtonian Rheology – Rapid Gelling The strongly positively charged small kosmotropic Mg++ atoms attract water (which is polar) in deep layers introduce a shear thinning property affecting the rheological properties and making concretes less “sticky” with added pozzolanIt is not known how deep these layers getEtc.Etc.Ca++ = 114, Mg++ = 86 picometres
57DurabilityConcretes are said to be less durable when they are physically or chemically compromised.Physical factors can result in chemical reactions reducing durabilityE.g. Cracking due to shrinkage can allow reactive gases and liquids to enter the concreteChemical factors can result in physical outcomes reducing durabilityE.g. Alkali silica reaction opening up cracks allowing other agents such as sulfate and chloride in seawater to enter.This presentation will describe benchmark improvements in durability as a result of using the new TecEco magnesia cement technologies
58Crack Collage Alkali aggregate Reaction Evaporative Crazing Shrinkage Drying ShrinkageThermalSettlement ShrinkageFreeze Thaw D CracksStructuralPlastic ShrinkagePhotos from PCA and US Dept. Ag WebsitesCorrosion RelatedAutogenous or self-desiccation shrinkage (usually related to stoichiometric or chemical shrinkage)TecEco technology can reduce if not solve problems of cracking:Related to (shrinkage) through open system loss of water.As a result of volume change caused by delayed reactionsAs a result of corrosion.Related to autogenous shrinkage
59Causes of Cracking in Concrete Cracking commonly occurs when the induced stress exceeds the maximum tensile stress capacity of concrete and can be caused by many factors including restraint, extrinsic loads, lack of support, poor design, volume changes over time, temperature dependent volume change, corrosion or delayed reactions.Causes of induced stresses include:Restrained thermal, plastic, drying and stoichiometric shrinkage, corrosion and delayed reaction strains.Slab curling.Loading on concrete structures.Cracking is undesirable for many reasonsVisible cracking is unsightlyCracking compromises durability because it allows entry of gases and ions that react with Portlandite.Cracking can compromise structural integrity, particularly if it accelerates corrosion.
60Graphic Illustration of Cracking Autogenous shrinkage has been used to refer to hydration shrinkage and is thus stoichiometricAfter Tony Thomas (Boral Ltd.) (Thomas 2005)
61Cracking due to Loss of Water Brucite gains weight in excess of the theoretical increase due to MgO conversion to Mg(OH)2 in samples cured at 98% RH.Dr Luc Vandepierre, Cambridge University, 20 September, 2005.Drying ShrinkageFoolPlastic ShrinkageEvaporative Crazing ShrinkageBucket of WaterSettlement ShrinkagePicture from:We may not be able to prevent too much water being added to concrete by fools. TecEco approach the problem in a different way by providing for the internal removal/storage of water that can provide for more complete hydration of PC.
62Solving Cracking due to Shrinkage from Loss of Water In the system water plus Portland cement powder plus aggregates shrinkage is in the order of .05 – 1.5 %.Shrinkage causes crackingThere are two main causes of Portland cements shrinking over time.Stoichiometric (chemical) shrinkage andShrinkage through loss of water.The solution is to:Add minerals that compensate by stoichiometrically expanding and/or toUse less water, internally hold water or prevent water loss.TecEco tec-cements internally hold water and prevent water loss.The kosmotropic nature of Mg++ makes water more viscous without shear.MgO (s) + H2O (l) ↔ Mg(OH)2.nH2O (s)
63Preventing Shrinkage through Loss of Water When magnesia hydrates it consumes 18 litres of water per mole of magnesia probably more depending on the value of n in the reaction below:MgO (s) + H2O (l) ↔ Mg(OH)2.nH2O (s)The dimensional change in the system MgO + PC depends on:The ratio of MgO to PCWhether water required for hydration of PC and MgO is coming from stoichiometric mix water (i.e. the amount calculated as required), excess water (bleed or evaporative) or from outside the system.In practice tec-cement systems are more closed and thus dimensional change is more a function of the ratio of MgO to PCAs a result of preventing the loss of water by closing the system together with expansive stoichiometry of MgO reactions (see below).↔ molar mass (at least!)liquid ↔ molar volumes (at least!)It is possible to significantly reduce if not prevent (drying, plastic, evaporative and some settlement) shrinkage as a result of water losses from the system.The molar volume (L.mol-1)is equal to the molar mass (g.mol-1) divided by the density (g.L-1).
64Preventing Shrinkage through Loss of Water Portland cements stoichiometrically require around % water for hydration yet we add approximately 45 to 60% at cement batching plants to fluidise the mix sufficiently for placement.If it were not for the enormous consumption of water by tri calcium aluminate as it hydrates forming ettringite in the presence of gypsum, concrete would remain as a weak mush and probably never set.26 moles of water are consumed per mole of tri calcium aluminate to from a mole of solid ettringite. When the ettringite later reacts with remaining tri calcium aluminate to form monosulfoaluminate hydrate a further 4 moles of water are consumed.The addition of reactive MgO achieves water removal internally in a closed system in a similar way.MgO (s) + H2O (l) ↔ Mg(OH)2.nH2O (s)
65Other Benefits of Preventing Shrinkage through Loss of Water Internal water consumption and prevention of loss also results in:Greater strengthMore complete hydration of PC .Reduced in situ voids:paste ratioGreater densityIncreased durabilityHigher short term alkalinityMore effective pozzolanic reactions.Small substitutions of PC by MgO result in water being trapped inside concrete as Brucite and Brucite hydrates which can later self desiccate delivering water to hydration reactions of calcium silicates (Preventing so called “Autogenous” shrinkage).
66Bleeding is a Bad Thing Better to keep concretes as closed systems Bleeding is caused by:Lack of finesToo much waterBleeding can be fixed by:Reducing water or adding finesAir entrainment or grading adjustmentsAdding kosmotropic ions like Mg++Bleeding causes:Reduced pumpabilityLoss of cement near the surface of concretesDelays in finishingPoor bond between layers of concreteInterconnected pore structures that allow aggressive agents to enter laterSlump and plastic cracking due to loss of volume from the systemLoss of alkali that should remain in the system for better pozzolanic reactionsLoss of pollutants such as heavy metals if wastes are being incorporated.Concrete is better as a closed systemBetter to keep concretes as closed systems
67Dimensional Control in Tec-Cement Concretes over Time By adding MgO volume changes are minimised to close to neutral.So far we have observed significantly less shrinkage in TecEco Tec - Cement concretes with about (8-10% substitution OPC) with or without fly ash.At some ratio, thought to be around 15-18% reactive magnesia there is no shrinkage.The water lost by concrete as it shrinks is used by the reactive magnesia as it hydrates eliminating shrinkage.Note that brucite is > mass% water and it makes sense to make binders out of water!More research is required to accurately establish volume relationships and causes for reduced shrinkage.
68Reducing Cracking as a Result of Volume Change caused by Delayed Reactions An Alkali Aggregate Reaction Cracked Bridge ElementPhoto Courtesy Ahmad Shayan ARRB
69Types of Delayed Reactions There are several types of delayed reactions that cause volume changes (generally expansion) and cracking.Alkali silica reactionsAlkali carbonate reactionsDelayed ettringite formationDelayed thaumasite formationDelayed hydration or dead burned lime or periclase.Delayed reactions cause dimensional distress, cracking and possibly even failure.
70Reducing Delayed Reactions Delayed reactions do not appear to occur to the same extent in TecEco cements.A lower long term pH results in reduced reactivity after the plastic stage.Potentially reactive ions are trapped in the structure of brucite.Ordinary Portland cement concretes can take years to dry out however the reactive magnesia in Tec-cement concretes consumes unbound water from the pores inside concrete.Magnesia dries concrete out from the inside. Reactions do not occur without water.
71Reduced Steel Corrosion Related Cracking Rusting Causes Dimensional DistressSteel remains protected with a passive oxide coating of Fe3O4 above pH 8.9.A pH of over 8.9 is maintained by the equilibrium Mg(OH)2 ↔ Mg++ + 2OH- for much longer than the pH maintained by Ca(OH)2 because:Brucite does not react as readily as Portlandite resulting in reduced carbonation rates and reactions with salts.Concrete with brucite in it is denser and carbonation is expansive, sealing the surface preventing further access by moisture, CO2 and salts.
72Reduced Steel Corrosion John Harrison Presentation AASMIC ConferenceReduced Steel CorrosionBrucite is less soluble and traps salts as it forms resulting in less ionic transport to complete a circuit for electrolysis and less corrosion.Free chlorides and sulfates originally in cement and aggregates are bound by magnesiumMagnesium oxychlorides or oxysulfates are formed. ( Compatible phases in hydraulic binders that are stable provided the concrete is dense and water kept out.)As a result of the above the rusting of reinforcement does not proceed to the same extent.Cracking or spalling due to rust does not occur
73Long Term pH controlImportant if you wish to also add wastesTecEco add reactive magnesia which hydrates forming brucite which is another alkali, but much less soluble, mobile or reactive than Portlandite.Brucite provides long term pH control.A pH in the range 10.5 – 11.2 is ideal in a concrete
74Steel Corrosion is Influenced by Long Term pH John Harrison Presentation AASMIC ConferenceSteel Corrosion is Influenced by Long Term pHIn TecEco cements the long term pH is governed by the low solubility and carbonation rate of brucite and is much lower at around , allowing a wider range of aggregates to be used, reducing problems such as AAR and etching. The pH is still high enough to keep Fe3O4 stable in reducing conditions.Eh-pH or Pourbaix Diagram The stability fields of hematite, magnetite and sideritein aqueous solution; total dissolved carbonate = 10-2M.Steel corrodes below 8.9Equilibrium pH of Brucite and of lime
75Reducing Cracking Related to Autogenous Shrinkage John Harrison Presentation AASMIC ConferenceReducing Cracking Related to Autogenous ShrinkageAutogenous shrinkage tends to occur in high performance concretes in which dense microstructures develop quickly preventing the entry of additional water required to complete hydration.First defined by Lynam in 1934 (Lynam CG. Growth and movement in Portland cement concrete. London: Oxford University Press; p )The autogenous deformation of concrete is defined as the unrestrained, bulk deformation that occurs when concrete is kept sealed and at a constant temperature.
76Reducing Cracking Related to Autogenous Shrinkage John Harrison Presentation AASMIC ConferenceReducing Cracking Related to Autogenous ShrinkageMain cause is stoichiometric or chemical shrinkage as observed by Le Chatelier.whereby the reaction products formed during the hydration of cement occupy less space than the corresponding reactants.A dense cement paste hydrating under sealed conditions will therefore self-desiccate creating empty pores within developing structure. If external water is not available to fill these “empty” pores, considerable shrinkage can result.Le Chatelier H. Sur les changements de volume qui accompagnent Ie durcissement des ciments. Bulletin de la Societe d'Encouragement pour I'Industrie Nationale 1900:54-7.
77Reducing Cracking Related to Autogenous Shrinkage John Harrison Presentation AASMIC ConferenceReducing Cracking Related to Autogenous ShrinkageAutogenous shrinkage does not occur in high strength Tec-Cement concretes because:The brucite hydrates that form desiccate back to brucite delivering water in situ for more complete hydration of Portland cement.Mg(OH)2.nH2O (s) ↔ MgO (s) + H2O (l)As brucite is a relatively weak mineral compressed and densifies the microstructure.The stoichiometric shrinkage of Portland cement (first observed by Le Chatelier) is compensated for by the stoichiometric expansion of magnesium oxide on hydration.MgO (s) + H2O (l) ↔ Mg(OH)2.nH2O (s)↔ molar mass (at least!)liquid ↔ molar volumes (at least 116% expansion, probably more initially before desiccation as above!)
78Improved DurabilityMaterials that last longer need replacing less often saving on energy and resources.Reasons for Improved Durability:Greater Density? = Lower PermeabilityPhysical Weaknesses => Chemical AttackRemoval of Portlandite with the Pozzolanic Reaction.Removal or reactive componentsSubstitution by Brucite => Long Term pH controlReducing corrosion
79Reduced PermeabilityAs bleed water exits ordinary Portland cement concretes it creates an interconnected pore structure that remains in concrete allowing the entry of aggressive agents such as SO4--, Cl- and CO2TecEco tec - cement concretes are a closed system. They do not bleed as excess water is consumed by the hydration of magnesia.As a result TecEco tec - cement concretes dry from within, are denser and less permeable and therefore stronger more durable and less permeable. Cement powder is not lost near the surfaces. Tec-cements have a higher salt resistance and less corrosion of steel etc.
80Greater Density – Lower Permeability Concretes have a high percentage (around 18% – 22%) of voids.On hydration magnesia expands >=116.9 % filling voids and surrounding hydrating cement grains => denser concrete.On carbonation to nesquehonite brucite expands 307% sealing the surface.Lower voids:paste ratios than water:binder ratios result in little or no bleed water, lower permeability and greater density.
81Densification During the Plastic Phase Water is required to plasticise concrete for placement, however once placed, the less water over the amount required for hydration the better. Magnesia consumes water as it hydrates producing solid material.Less water results in increased density and concentration of alkalis - less shrinkage and cracking and improved strength and durability.
82Durability - Reduced Salt & Acid Attack Brucite has always played a protective role during salt attack. Putting it in the matrix of concretes in the first place makes sense.Brucite does not react with salts because it is a least 5 orders of magnitude less soluble, mobile or reactive.Ksp brucite = 1.8 X 10-11Ksp Portlandite = 5.5 X 10-6TecEco cements are more acid resistant than Portland cementThis is because of the relatively high acid resistance (?) of Lansfordite and nesquehonite compared to calcite or aragonite
83Less Freeze - Thaw Problems Denser concretes do not let water in.Brucite will to a certain extent take up internal stressesWhen magnesia hydrates it expands into the pores left around hydrating cement grains:MgO (s) + H2O (l) ↔ Mg(OH)2 (s)↔ molar mass↔ molar volumes↔ molar volumesAt least 38% air voids are created in space that was occupied by magnesia and water!Air entrainment can also be used as in conventional concretesTecEco concretes are not attacked by the salts used on roads
84Rosendale Concretes – Proof of Durability Rosendale cements contained 14 – 30% MgOA major structure built with Rosendale cements commenced in 1846 was Fort Jefferson near key west in Florida.Rosendale cements were recognized for their exceptional durability, even under severe exposure. At Fort Jefferson much of the 150 year-old Rosendale cement mortar remains in excellent condition, in spite of the severe ocean exposure and over 100 years of neglect. Fort Jefferson is nearly a half mile in circumference and has a total lack of expansion joints, yet shows no signs of cracking or stress. The first phase of a major restoration is currently in progress.More information from
85Solving Waste & Logistics Problems TecEco cementitious composites represent a cost affective option forusing non traditional aggregates from on site reducing transports costs and emissionsuse and immobilisation of waste.Because they havelower reactivityless waterlower pHReduced solubility of heavy metalsless mobile saltsgreater durability.denser.impermeable (tec-cements).dimensionally more stable with less shrinkage and cracking.homogenous.no bleed water.TecEco Technology - Converting Waste to Resource
86Role of Brucite in Immobilization In a Portland cement Brucite matrixPC derive CSH takes up lead, some zinc and germaniumPozzolanic CSH can take up mobile cationsBrucite and hydrotalcite are both excellent hosts for toxic and hazardous wastes.Heavy metals not taken up in the structure of Portland cement minerals or trapped within the brucite layers end up as hydroxides with minimal solubility.The Brucite in TecEco cements has a structure comprising electronically neutral layers and is able to accommodate a wide variety of extraneous substances between the layers and cations of similar size substituting for magnesium within the layers and is known to be very suitable for toxic and hazardous waste immobilisation.Layers of electronically neutral brucite suitable for trapping balanced cations and anions as well as other substances.Salts and other substances trapped between the layers.Van de waals bonding holding the layers together.
87Lower Solubility of Metal Hydroxides There is a 104 differenceAll waste streams will contain heavy metals and a strategy for long term pH control is therefore essential
88John Harrison Presentation AASMIC Conference Using Wastes and Non-Traditional Aggregates to Make TecEco Cement ConcretesMany wastes and local materials can contribute physical property values.Plastics for example are collectively light in weight, have tensile strength and low conductance.Tec, eco and enviro-cements will allow a wide range of wastes and non-traditional aggregates such as local materials to be used.Tec, enviro and eco-cements are benign binders that are:low alkali reducing reaction problems with organic materials.stick well to most included wastesTec, enviro and eco-cements can utilize wastes including carbon to increase sequestration preventing their conversion to methaneThere are huge volumes of concrete produced annually (>2 tonnes per person per year)CONVERTING WASTES TO RESOURCEMany wastes and local materials can contribute physical property values.Tec, Eco and Enviro-Cements will allow a wide range of wastes and non-traditional aggregates such as local materials to be used.
89Sustainable Materials in the Built Environment - 2007 Technical FocusThis Conference will focus on:The impacts and connectivity of different parts of the supply chain.Fabrication, performance, recycling and wasteNew developments in materials and processesReviewing existing materials assessment toolsFuture directions in regulationOpportunities/barriers to introduction of sustainable materials and technologies in the building industry.New materials and more sustainable built environments: the evidence?Sustainable Materials in the Built Environment Innovation - Process – Design Announcement and Call for Papers18th to 20th February 2007Melbourne, AustraliaJoint Venture Websites ASSMIC Website: Materials Australia Website: