Presentation on theme: "Greening the Heartland"— Presentation transcript:
1 Greening the Heartland John Harrison Presentation AASMIC ConferenceGreening the HeartlandEarthship Brighton (UK) – The first building utilising TecEco eco-cementsI will have to race over some slides but the presentation is always downloadable from the TecEco web site if you missed something John Harrison B.Sc. B.Ec. FCPA.
2 Relevance to Canada Help Canada meet Kyoto objectives Magnesium industry in doldrumsCollapse of the asbestos industryExport Industry?Near USAClose to EuropeMg silicate minerals for sequestration in power stations.Reactive magnesia.MgO products with carbon credits attached?
3 The Problem – A Planet in Crisis TecEco are in the BIGGEST Business on the Planet - Solving Sustainability Problems Economically
4 A 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.
5 Atmospheric Carbon Dioxide John Harrison Presentation AASMIC ConferenceAtmospheric Carbon DioxideATMOSPHERIC 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.
6 Global Temperature Anomaly John Harrison Presentation AASMIC ConferenceGlobal Temperature AnomalyGLOBAL 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.
7 The Techno-Process Detrimental affects on earth systems Global 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
8 Ecological 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
9 Canada Before Settlement John Harrison Presentation AASMIC ConferenceCanada Before SettlementHUGE MATERIALS FLOWS IN THE BUILT ENVIRONMENTThe built environment is our footprint, a major proportion of the techno-sphere and our lasting legacy on the planet. In this dominant proportion of all materials flows and unsustainable practices abound from the logging of old growth forests to the high volume of wastage at landfill.The dominant proportion of what we take, manipulate and make that we do not consume immediately goes into the materials with which we build the built environment or “techno-sphere”. Buildings and infrastructure probably account for around 70% of all materials flows (TecEco estimate).Buildings alone account for 40 percent of the materials and about a third of the energy consumed by the world economy.Construction activities contributed over 35% of total global CO2 emissions in 1999.According to the Green Building Council of Australia Building waste is 40% of all waste going to landfill in Australia.
10 John Harrison Presentation AASMIC Conference Canada NowPaper Mill - Soda liquor + ClHabitat removalFarming - Pesticide, N & KVehicles - carbon dioxideCows - methaneHUGE MATERIALS FLOWS IN THE BUILT ENVIRONMENTThe built environment is our footprint, a major proportion of the techno-sphere and our lasting legacy on the planet. In this dominant proportion of all materials flows and unsustainable practices abound from the logging of old growth forests to the high volume of wastage at landfill.The dominant proportion of what we take, manipulate and make that we do not consume immediately goes into the materials with which we build the built environment or “techno-sphere”. Buildings and infrastructure probably account for around 70% of all materials flows (TecEco estimate).Buildings alone account for 40 percent of the materials and about a third of the energy consumed by the world economy.Construction activities contributed over 35% of total global CO2 emissions in 1999.According to the Green Building Council of Australia Building waste is 40% of all waste going to landfill in Australia.CitiesImmediate and polluted water run-off. Air pollution. Carbon dioxide and other gases. Other wastes. Huge linkages.Huge impacts
11 Canada with a Little Lateral Thinking & Effort John Harrison Presentation AASMIC ConferenceCanada with a Little Lateral Thinking & EffortLess paper. Other Cl free processes - no salinityTecEco technology provides ways of sequestering carbon dioxide and utilizing wastes to create our techno - worldEvolution away from using trees – paperless officeOrganic farming. Carbon returned to soils. Use of zeolite reduces water and fertilizer required by 2/3Cows – CSIRO anti methane bredVehicles – more efficient and using fuel cellsSequestration processesCities:Porous pavement prevents immediate and polluted run-off. Carbon dioxide and other gases absorbed by TecEco eco-cements. Less wastes. Carbon based wastes converted to energy or mulches and returned to soils. Buildings generate own energy etc.HUGE MATERIALS FLOWS IN THE BUILT ENVIRONMENTThe built environment is our footprint, a major proportion of the techno-sphere and our lasting legacy on the planet. In this dominant proportion of all materials flows and unsustainable practices abound from the logging of old growth forests to the high volume of wastage at landfill.The dominant proportion of what we take, manipulate and make that we do not consume immediately goes into the materials with which we build the built environment or “techno-sphere”. Buildings and infrastructure probably account for around 70% of all materials flows (TecEco estimate).Buildings alone account for 40 percent of the materials and about a third of the energy consumed by the world economy.Construction activities contributed over 35% of total global CO2 emissions in 1999.According to the Green Building Council of Australia Building waste is 40% of all waste going to landfill in Australia.Less impacts
12 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 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 annumTecEco Pty. Ltd. have benchmark technologies for improvement in sustainability and properties
13 Embodied Energy of Building Materials Concrete is relatively environmentally friendly and has a relatively low embodied energyDownloaded from (last accessed 07 March 2000)
14 Average Embodied Energy in Buildings Most of the embodied energy in the built environment is in concrete.But because so much is used there is a huge opportunity for sustainability by reducing the embodied energy, reducing the carbon debt (net emissions) and improving properties.Downloaded from (last accessed 07 March 2000)
15 Emissions from Cement Production Chemical ReleaseThe process of calcination involves driving off chemically bound CO2 with heat.CaCO3 →CaO + ↑CO2∆Process 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%(1) of global anthropogenic CO2.(1) Pearce, F., "The Concrete Jungle Overheats", New Scientist, 19 July, No 2097, 1997 (page 14).
17 + + Sustainability Sustainability is a direction not a destination. Our approach should be holistically balanced and involveEverybody, every process, every day.++Emissions reduction through efficiency and conversion to non fossil fuelsMineral Sequestration Eco-cements in cities + Waste utilizationGeological Seques-tration
18 Converting Waste to Resource John Harrison Presentation AASMIC ConferenceConverting Waste to ResourceRecycleWaste only what is biodegradable or can be re-assimilatedTake only renewables→ Manipulate → Make → Use →Reuse Re-make[ ←Materials→ ][← Underlying molecular flows →]Materials control: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.Problems in the global commons today include heavy metals, halogen carbon double bond compounds, CFC’s too much CO2 etc.
19 Innovative New Materials - the Key to Sustainability The choice of materials in construction 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
20 Sustainability Through Materials Innovation Problems in the global commons today can only be changed by changing the molecular flows underlying planetary anthropogenic materials flows in the techno-process so that the every day behaviors of people interacting in an economic system will deliver new more sustainable flows.This will not happen because it is the right thing to do. Pilzer's first law states that the technology paradigm defines resources. Changing the flow of materials therefore has to be economic.WBCSD President Björn Stigson 26 November 2004 “Technology is a key part of the solutions for sustainable development. Innovation and technology are tools for achieving higher resource efficiency in society.”
21 Sustainability = 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 shiftECONOMICSDemandIncrease 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
22 Huge Potential for Sustainable 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 comprise70% of materials flows (buildings, infrastructure etc.)40-45% of waste that goes to landfill (15 % of new materials going to site are wasted.)Reducing the impact of the take and waste phases of the techno-process.By including carbon in materials they are potentially carbon sinks.By including wastes for physical properties as well as chemical composition they become resourcesCWaste
23 Innovative New Materials Vital It is possible to achieve Kyoto targets as the UK are proving, but we need to go way beyond the treaty according to our chief scientists.Carbon rationing has been proposed as the only viable means to keep the carbon dioxide concentration in the atmosphere below 450 ppm.Atmospheric carbon reduction is essential, but difficult to politically achieve by rationing.Making the built environment not only a repository for recyclable resources (referred to as waste) but a huge carbon sink is an alternative and adjunct that is politically viable as it potentially results in economic benefits.Concrete, a cementitous composite, is the single biggest material flow on the planet with over 2.2 tonnes per person produced.Eco-cements offer tremendous potential for capture and sequestration using cementitious composites.MgCO3 → MgO + ↓CO2 - Efficient low temperature calcination & capture MgO + ↓CO2 + H2O → MgCO3.3H2O - Sequestration as building material ∆
24 Sustainability Summary John Harrison Presentation AASMIC ConferenceSustainability SummaryA more holistic approach is to reduce energy consumption as well as sequester carbon.To reduce our linkages with the environment we must convert waste to resource (recycle).Sequestration and recycling have to be economic processes or they have no hope of success.We cannot stop progress, but we can change and historically economies thrive on change.What can be changed is the technical paradigm. CO2 and wastes need to be redefined as resources.New and better materials are required that utilize wastes including CO2 to create a wide range of materials suitable for use in our built environment.
25 John Harrison Presentation AASMIC Conference TecEco TechnologyMore information at
26 The TecEco Total Process Serpentine Mg3Si2O5(OH)4Olivine Mg2SiO4CrushingCrushingGrindingCO2 from Power Generation or IndustryGrindingWaste Sulfuric Acid or Alkali?ScreeningScreeningMagnetic Sep.Silicate Reactor ProcessIron Ore.Gravity ConcentrationHeat 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).5.7237.506MgO for TecEco Cements and Sequestration by Eco-Cements in the Built Environment
27 Why Magnesium Compounds John Harrison Presentation AASMIC ConferenceWhy Magnesium CompoundsAt 2.09% of the crust magnesium is the 8th most abundant element.Magnesium oxide is easy to make using non fossil fuel energy and efficiently absorbs CO2Because magnesium has a low molecular weight, proportionally a much greater amount of CO2 is released or captured.A high proportion of water means that a little binder goes a long way. In terms of binder produced for starting material in cement, eco-cements are nearly six times more efficient.WHY MAGNESIUM COMPOUNDSBecause magnesium has a low molecular weight, proportionally a much greater amount of CO2 is released or captured.This, together with the high proportion of water in the binder is what makes construction the built environment out of CO2 and water so exciting.Imagine the possibilities if CO2 could be captured during the manufacture of eco-cement!
28 TecEco Technologies 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 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.TecEcoEconomic under Kyoto?TecEco
29 TecEco Kiln Technology John Harrison Presentation AASMIC ConferenceTecEco Kiln TechnologyGrinds and calcines at the same time.Runs 25% to 30% more efficiency.Can be powered by solar energy or waste heat.Brings mineral sequestration and geological sequestration togetherCaptures CO2 for bottling and sale to the oil industry (geological sequestration).The products – CaO &/or MgO can be used to sequester more CO2 and then be re-calcined. This cycle can then be repeated.Suitable for making reactive reactive MgO.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.
30 John Harrison Presentation AASMIC Conference A Post – Carbon AgeECO-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 sustainableWe all use carbon and wastes to make our homes! “Biomimicry”
31 Drivers for TecEco Technology Government InfluenceCarbon TaxesProvision of Research FundsEnvironmental educationTecEco kiln technology could be the first non fossil fuel powered industrial processConsumer PullEnvironmental sentiment Cost and technical advantages? Competition?Huge MarketsCement 2 billion tonnes.Bricks 130,000 million tonnesProducer PushThe opportunity cost of compliant waste disposalProfitability and cost recoveryTechnical meritResource issuesRoboticsResearch objectivesTecEco cements are the only binders capable of utilizing very large quantities of wastes based on physical property rather than chemical composition overcoming significant global disposal problems, and reducing the impact of landfill taxes.TecEco eco-cements can sequester CO2 on a large scale and will therefore provide carbon accounting advantages.
32 Drivers for Change – Robotics John Harrison Presentation AASMIC ConferenceDrivers for Change – RoboticsUsing Robots to print buildings is all quite simple from a software, computer hardware and mechanical engineering point of view.The problem is in developing new construction materials with the right flow characteristics so they can be squeezed out like toothpaste, yet retain their shape until hardenedOnce new materials suitable for the way robots work have been developed economics will drive the acceptance of robots for constructionConcretes for example will need to evolve from being just a high strength grey material, to a smorgasbord of composites that can be squeezed out of a variety of nozzles for use by a robotic workforce for the varying requirements of a structureTecEco cement concretes have the potential of achieving the right shear thinning characteristics requiredDRIVERS FOR CHANGE - ROBOTICSUsing Robots to print buildings is all quite simple from a software, computer hardware and mechanical engineering point of view.The problem is in developing new construction materials with the right flow characteristics so they can be squeezed out like toothpaste, yet retain their shape until hardenedOnce new materials suitable for the way robots work have been developed economics will drive the acceptance of robots for constructionConcretes for example will need to evolve from being just a high strength grey material, to a smorgasbord of composites that can be squeezed out of a variety of nozzles for use by a robotic workforce for the varying requirements of a structureTecEco cement concretes have the potential of achieving the right shear thinning characteristics required
33 John Harrison Presentation AASMIC Conference TecEco CementsMore information atMore slides on web site
34 John 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.
35 The Magnesium Thermodynamic Cycle John Harrison Presentation AASMIC ConferenceThe Magnesium Thermodynamic CycleECO-CEMENTS AND THE MAGNESIUM THERMODYNAMIC CYCLEEco-cements have an almost unfair sustainability advantage as they utilise the magnesium thermodynamic cycle.Important features:It is a cycle,Relatively speaking it does not take much energy to make it go around and aroundCalcining can be done at relatively low temperatures.Calcining can therefore be carried out in a closed system and the CO2 captured.Grinding and calcining at the same time also makes sense as some 30% of the energy in a conventional cement plant goes into the grinding process.Eco-cements in a relatively porous matrix such as a concrete block, porous road pavement or mortar complete the cycle by gaining strength by carbonating, the CO2 required coming out of the surrounding air.
36 TecEco Cement Sustainability John Harrison Presentation AASMIC ConferenceTecEco Cement SustainabilityTecEco technology will be pivotal in bringing about sustainability in the built environment.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 25 = 30% less total binder is required for the same strength.Eco-cements carbonate sequestering CO2Both 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 culletDurability 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.
37 John 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.
38 TecEco Cement Technology John Harrison Presentation AASMIC ConferenceTecEco Cement TechnologyPortlandite (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 forming brucite which is another alkali, but much less soluble, mobile or reactive than Portlandite.In Eco-cements brucite carbonatesThe consequences of need to be considered.
39 Why Add Reactive Magnesia? John Harrison Presentation AASMIC ConferenceWhy Add Reactive Magnesia?To maintain the long term stability of CSH.Maintains alkalinity preventing the reduction in Ca/Si ratio.To remove water.Reactive magnesia consumes water as it hydrates to possibly hydrated forms of brucite.To reduce shrinkage.The consequences of putting brucite through the matrix of a concrete in the first place need to be considered.To make concretes more durableBecause significant quantities of carbonates are produced in porous substrates which are affective binders.Reactive MgO is a new tool to be understood with profound affects on most properties
40 What is Reactive MgO? or Lattice Energy Destroys a Myth John Harrison Presentation AASMIC ConferenceWhat is Reactive MgO? or 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 (Ramachandran V. S., Concrete Science, Heydon & Son Ltd. 1981, p )
41 Summary of Reactions Involved John Harrison Presentation AASMIC ConferenceSummary of Reactions InvolvedWe think the reactions are relatively independent.Notice the low solubility of brucite compared to Portlandite and that nesquehonite adopts a more ideal habit than calcite & aragonite
42 Strength with Blend & Porosity John Harrison Presentation AASMIC ConferenceStrength with Blend & PorosityTec-cement concretesEco-cement concretesHigh PorosityEnviro-cement concretesHigh OPCHigh MagnesiaSTRENGTH ON ARBITARY SCALE 1-100
43 Tec-Cement Concrete Strength Gain Curve Concretes are more often than not made to strength.The use of tec-cement results in20-30% greater strength or less binder for the same strength.more rapid early strength development even with added pozzolans.Straight line strength development for a long timestrength gain with less cement and added pozzolans is of great economic and environmental importance.
44 Reasons for Strength Development in Tec-Cements. Reactive magnesia requires considerable water to hydrate resulting in:Denser, less permeable concrete.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.)Slow release of water from hydrated Mg(OH)2.nH2O supplying H2O for more complete hydration of C2S and C3S?Formation of MgAl hydrates? Similar to flash set in concrete but slower??
45 Water Reduction 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 less shrinkage and cracking and improved strength and durability. Concentration of alkalis and increased density result in greater strength.
46 Tec-Cement Compressive Strength Graphs by Oxford Uni Student
47 Tec-Cement Tensile Strength Graphs by Oxford Uni StudentTensile strength is thought to be caused by change in surface charge on MgO particles from +ve to –ve at Ph 12 and electrostatic attractive forces
48 Other Strength Testing to Date BRE (United Kingdom)2.85PC/0.15MgO/3pfa(1 part) : 3 parts sand - Compressive strength of 69MPa at 90 days.Note that there was as much pfa as Portland cement plus magnesia. Strength development was consistently greater than the OPC controlTecEco Large Cement CompanyModified 20 MPa mix
49 Increased Density – Reduced Permeability Concretes have a high percentage (around 18% - 25%) of voids.On hydration magnesia expands % filling voids and surrounding hydrating cement grains and compensates for the shrinkage of Portland cement.Brucite is mass% water.Lower voids:paste ratios than water:binder ratios result in little or no bleed water less permeability and greater density.Compare the affect to that of vacuum dewatering.
50 Reduced 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.Consequences:Tec - cement concretes tend to dry from within, are denser and less permeable and therefore stronger more durable and more waterproof. Cement powder is not lost near the surfaces.Tec-cements have a higher salt resistance and less corrosion of steel etc.
52 Lower More Stable Long Term pH with Less Corrosion In 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 8.9
53 Reduced Steel Corrosion Steel 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.Brucite 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.)
54 Corrosion in Portland Cement Concretes Both carbonation, which renders the passive iron oxide coating unstable or chloride attack (various theories) result in the formation of reaction products with a higher electrode potential resulting in anodes with the remaining passivated steel acting as a cathode.Passive Coating Fe3O4 intactCorrosionAnode: Fe → Fe+++ 2e- Cathode: ½ O2 + H2O +2e- → 2(OH)- Fe++ + 2(OH)- → Fe(OH)2 + O2 → Fe2O3 and Fe2O3.H2O (iron oxide and hydrated iron oxide or rust)The role of chloride in CorrosionAnode: Fe → Fe+++ 2e- Cathode: ½ O2 + H2O +2e- → 2(OH)- Fe++ +2Cl- → FeCl2 FeCl2 + H2O + OH- → Fe(OH)2 + H+ + 2Cl- Fe(OH)2 + O2 → Fe2O3 and Fe2O3.H2OIron hydroxides react with oxygen to form rust. Note that the chloride is “recycled” in the reaction and not used up.
55 Reduced Delayed Reactions A wide range of delayed reactions can occur in Portland cement based concretesDelayed alkali silica and alkali carbonate reactionsThe delayed formation of ettringite and thaumasiteDelayed hydration of minerals such as dead burned lime and magnesia.Delayed reactions cause dimensional distress and possible failure.
56 Reduced Delayed Reactions (2) 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, probably holding it for slow release to extended hydration reactions of Ca silicates.Magnesia dries concrete out from the inside. Reactions do not occur without water.
57 Durability - Reduced Salt & Acid Attack Brucite has always played a protective role during salt attack. Putting it in the matrix of concretes in introduces considerable durability.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
58 Bingham Plastic Rheology Finely ground reactive magnesia consumes water but also acts as a plasticiserThere are also surface charge affects
59 Bingham Plastic Rheology It is not known how deep these layers getThe strongly positively charged small Mg++ atoms attract water (which is polar) in deep layers affecting the rheological properties and making concretes less “sticky” with added pozzolanEtc.Etc.Ca++ = 114, Mg++ = 86 picometres
60 Rheology TecEco concretes and mortars are: Very homogenous and do not segregate easily. They exhibit good adhesion and have a shear thinning property.Exhibit Bingham plastic qualities and react well to energy input.Have good workability.TecEco concretes with the same water/binder ratio have a lower slump but greater plasticity and workability.A range of pumpable composites with Bingham plastic properties will be required in the future as buildings will be “printed.”
61 Reduced ShrinkageNet shrinkage is reduced due to stoichiometric expansion of Magnesium minerals, and reduced water loss.Dimensional change such as shrinkage results in cracking and reduced durability
62 Reduced Shrinkage – Less Cracking Cracking, the symptomatic result of shrinkage, is undesirable for many reasons, but mainly because it allows entry of gases and ions reducing durability. Cracking can be avoided only if the stress induced by the free shrinkage strain, reduced by creep, is at all times less than the tensile strength of the concrete. Tec-cements also have greater tensile strength.Large Cement CompanyTest Age (days)Microstrain7133142402831656470Tec-cements exhibit higher tensile strength and less shrinkage and therefore less cracking
63 Volume Changes on Hydration When magnesia hydrates it expands:MgO (s) + H2O (l) ↔ Mg(OH)2.nH2O (s)↔ (minimum) molar massliquid ↔ (minimum) molar volumesUp to % solidus expansion depending on whether the water is coming from stoichiometric mix water, bleed water or from outside the system. In practice less as the water comes from mix and bleed water.The molar volume (L.mol-1)is equal to the molar mass (g.mol-1) divided by the density (g.L-1).
64 Volume Changes on Carbonation Consider what happens when Portlandite carbonates:Ca(OH)2 + CO2 CaCO3↔ 100 molar massgas ↔ molar volumesSlight expansion. But shrinkage from surface water lossCompared to brucite forming nesquehonite as it carbonates:Mg(OH)2 + CO2 MgCO3.3H2O↔ molar massgas ↔ molar volumes307 % expansion (less water volume reduction) and densification of the surface preventing further ingress of CO2 and carbonation. Self sealing?The molar volume (L.mol-1)is equal to the molar mass (g.mol-1) divided by the density (g.L-1).
65 Dimensionally Control Over Concretes During Curing? Portland cement concretes shrink around .05%. Over the long term much more (>.1%).Mainly due to plastic and drying shrinkage.The use of some wastes as aggregates causes shrinkage e.g. wood waste in masonry units, thin panels etc.By varying the amount and form of magnesia added dimensional control can be achieved.
66 TecEco Cement Concretes –Dimensional Control Combined – Hydration and Carbonation can be manipulated to be close to neutral.So far we have not observed significant shrinkage in TecEco tec - cement concretes (5% -10% substitution OPC) also containing fly ash.At some ratio, thought to be around 10% reactive magnesia and 90% PC volume changes are optimised as higher additions of MgO reduce strength.The water lost by Portland cement as it shrinks is used by reactive magnesia as it hydrates also reducing shrinkage.
67 Tec - Cement Concretes – Less or no Dimensional Change It may be possible to engineer a particle with slightly delayed expansion to counterbalance the expansion and then shrinkage concretes containing gbfs.
68 Less 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 volumes38% 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
69 John 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 nearly six times 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.
71 Eco-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 volumentric expansion from magnesium oxide to lansfordite is for example 473 volume %.
72 Eco-Cement Concrete 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.
74 CarbonationBecause magnesium has a low molecular weight, proportionally a greater amount of CO2 is captured.Carbonation results in significant sequestration because of the shear volumes involved.Carbonation adds strength.Carbonates are the stable phases of both calcium and magnesium.The formation of carbonates lowers the pH of concretes compromising the stability of the passive oxide coating on steel.Some steel reinforced structural concrete could be replaced with fibre reinforced porous carbonated concrete.
75 Chemistry of Carbonation 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.
76 Ramifications of Carbonation Magnesium Carbonates.The magnesium carbonates that form at the surface of tec – cement concretes expand significantly thereby sealing off further carbonation.Lansfordite and nesquehonite are stronger and more acid resistant than calcite or aragonite.The curing of eco-cements in a moist - dry alternating environment seems to encourage carbonation.Portland Cement ConcretesCarbonation proceeds relatively rapidly at the surface. Vaterite followed by Aragonite and Calcite is the principal product and lowers the pH to around 8.2
77 Proof of Carbonation - Minerals Present After 18 Months XRD showing carbonates and other minerals before removal of carbonates with HCl in a simple Mix (70 Kg PC, 70 Kg MgO, colouring oxide .5Kg, sand unwashed 1105 Kg)
78 Proof of Carbonation - Minerals Present After 18 Months and Acid Leaching XRD Showing minerals remaining after their removal with HCl in a simple mix (70 Kg PC, 70 Kg MgO, colouring oxide .5Kg, sand unwashed 1105 Kg)
79 TecEco Binders - Solving Waste Problems There are huge volumes of concrete produced annually ( 2 tonnes per person per year.)An important objective should be to make cementitous composites that can utilise wastes.TecEco cements provide a benign environment suitable for waste immobilisationMany wastes such as fly ash, sawdust , shredded plastics etc. can improve a property or properties of the cementitious composite.There are huge materials flows in both wastes and building and construction. TecEco technology will lead the world in the race to incorporate wastes in cementitous composites
80 TecEco Binders - Solving Waste Problems (2) TecEco cementitious composites represent a cost affective option for both use and immobilisation of waste.Lower 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
81 Role of Brucite in Immobilization In a Portland cement brucite matrixPC takes up lead, some zinc and germaniumBrucite 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.Van der waals bonding holding the layers together.Salts and other substances trapped between the layers.
82 Lower Solubility of Metal Hydroxides There is a 104 difference
83 TecEco Materials as Fire Retardants The main phase in TecEco tec - cement concretes is Brucite.The main phases in TecEco eco-cements are Lansfordite and nesquehonite.Brucite, Lansfordite and nesquehonite are excellent fire retardants and extinguishers.At relatively low temperaturesBrucite releases water and reverts to magnesium oxide.Mg(OH)2 ↔ MgO + H2OLansfordite and nesquehonite releases CO2 and water and convert to magnesium oxide.MgCO3.nH2O ↔ MgO + CO2 + H2OFires are therefore not nearly as aggressive resulting in less damage to structures.Damage to structures results in more human losses that direct fire hazards.
85 High Performance-Lower Construction Costs Less binders (OPC + magnesia) for the same strength.Faster strength gain even with added pozzolans.Elimination of shrinkage reducing associated costs.Tolerance and consumption of water.Reduction in bleed water enables finishing of lower floors whilst upper floors still being poured and increases pumpability.Cheaper binders as less energy requiredIncreased durability will result in lower costs/energies/emissions due to less frequent replacement.Because reactive magnesia is also an excellent plasticiser, other costly additives are not required for this purpose.A wider range of aggregates can be utilised without problems reducing transport and other costs/energies/emissions.Foolproof Concrete?
86 TecEco Concretes - Lower Construction Costs (2) Homogenous, do not segregate with pumping or work.Easier placement and better finishing.Reduced or eliminated carbon taxes.Eco-cements can to a certain extent be recycled.TecEco cements utilise wastes many of which improve properties.Improvements in insulating capacity and other properties will result in greater utility.Products utilising TecEco cements such as masonry and precast products can in most cases utilise conventional equipment and have superior properties.A high proportion of brucite compared to Portlandite is water and of Lansfordite and nesquehonite compared to calcite is CO2.Every mass unit of TecEco cements therefore produces a greater volume of built environment than Portland and other calcium based cements. Less need therefore be used reducing costs/energy/emissions.
87 Summary Simple, smart and sustainable? TecEco cement technology has resulted in potential solutions to a number of problems with Portland and other cements including shrinkage, durability and corrosion and the immobilisation of many problem wastes and will provides a range of more sustainable building materials.The right technology at the right time?TecEco cement technology addresses important triple bottom line issues solving major global problems with positive economic and social outcomes.Climate ChangePollutionDurabilityCorrosionStrengthDelayed ReactionsPlacement , FinishingRheologyShrinkageCarbon Taxes
89 The Use of Eco-Cements for Building Earthship Brighton John Harrison Presentation AASMIC ConferenceThe Use of Eco-Cements for Building Earthship BrightonBy Taus Larsen, (Architect, Low Carbon Network Ltd.)The Low Carbon Network (www.lowcarbon.co.uk) was established to raise awareness of the links between buildings, the working and living patterns they create, and global warming and aims to initiate change through the application of innovative ideas and approaches to construction. England’s first Earthship is currently under construction in southern England outside Brighton at Stanmer Park and TecEco technologies have been used for the floors and some walling.EARTHSHIP BRIGHTONThis slide shows the interior and exterior of Earthship Brighton in the UK.Earthships are exemplars of low-carbon design, construction and living and were invented and developed in the USA by Mike Reynolds over 20 years of practical building exploration. They are autonomous earth-sheltered buildings independent from mains electricity, water and waste systems and have little or no utility costs.For information about the Earthship Brighton and other projects please go to the TecEco web site.
90 Repair of Concrete Blocks. Clifton Surf Club John Harrison Presentation AASMIC ConferenceRepair of Concrete Blocks. Clifton Surf ClubThe Clifton Surf Life Saving Club was built by first pouring footings, On the footings block walls were erected and then at a later date concrete was laid in between.As the ground underneath the footings was sandy, wet most of the time and full of salts it was a recipe for disaster.Predictably the salty water rose up through the footings and then through the blocks and where the water evaporated there was strong efflorescence, pitting, loss of material and damage.The TecEco solution was to make up a formulation of eco-cement mortar which we doctored with some special chemicals to prevent the rise of any more moisture and salt.The solution worked well and appears to have stopped the problem.REPAIR JOB CLIFTON SURF CLUBThe Clifton Surf Life Saving Club was built by first pouring footings, On the footings block walls were erected and then at a later date concrete was laid in between.As the ground underneath the footings was sandy, wet most of the time and full of salts it was a recipe for disaster.Predictably the salty water rose up through the footings and then through the blocks and where the water evaporated there was strong efflorescence, pitting, loss of material and damage.formulation of eco-cement mortar which we doctored with some special chemicals to prevent the rise of any more moisture and salt.The solution worked well and appears to have stopped the problem.
91 Mike Burdon’s Murdunna Works John Harrison Presentation AASMIC ConferenceMike Burdon’s Murdunna WorksMike Burdon, Builder and Plumber.I work for a council interested in sutainability and have been involved with TecEco since around 2001 in a private capacity helping with large scale testing of TecEco tec-cements at our shack.I am interested in the potentially superior strength development and sustainability aspects.To date we have poured two slabs, footings, part of a launching ramp and some tilt up panels using formulations and materials supplied by John Harrison of TecEco. I believe that research into the new TecEco cements essential as overall I have found:The rheological performance even without plasticizer was excellent. As testimony to this the contractors on the site commented on how easy the concrete was to place and finish.We tested the TecEco formulations with a hired concrete pump and found it extremely easy to pump and place. Once in position it appeared to “gel up” quickly allowing stepping for a foundation to a brick wall.Strength gain was more rapid than with Portland cement controls from the same premix plant and continued for longer.The surfaces of the concrete appeared to be particularly hard and I put this down to the fact that much less bleeding was observed than would be expected with a Portland cement only formulationMIKE BURDON’S MURDUNNA WORKSMike is a plumber and a friend of mine.We have built footings, two slabs and some tilt ups at his shack.
92 Tec-Cement Slab Whittlesea, Vic. Australia On 17th March 2005 TecEco poured the first commercial slab in the world using tec-cement concrete with the assistance of one of the larger cement and pre-mix companies.The formulation strategy was to adjust a standard 20 MPa high fly ash (36%) mix from the company as a basis of comparison.Strength development, and in particular early strength development was good. Interestingly some 70 days later the slab is still gaining strength at the rate of about 5 MPa a month.Also noticeable was the fact that the concrete was not as "sticky" as it normally is with a fly ash mix and that it did not bleed quite as much.Shrinkage was low. 7 days micro strains, 14 days micro strains, 28 days micros strains and at 56 days microstrains.
94 CO2 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.
95 John Harrison Presentation AASMIC Conference Energy – On a Mass BasisRelative to Raw Material Used to make CementFrom Manufacturing Process Energy Release 100% Efficient (MJ.tonne-1)From Manufacturing Process Energy Release with Inefficiencies (MJ.tonne-1)Relative Product Used in CementRelative to Mineral Resulting in CementCaCO3 + ClayPortland Cement1807Hydrated OPCCaCO3Ca(OH)2MgCO3MgOMg(OH)2
96 Energy – On a Volume Basis John Harrison Presentation AASMIC ConferenceEnergy – On a Volume BasisRelative to Raw Material Used to make CementFrom Manufacturing Process Energy Release 100% Efficient (MJ.metre-3)From Manufacturing Process Energy Release with Inefficiencies (MJ.metre-3)Relative Product Used in CementRelative to Mineral Resulting in CementCaCO3 + ClayPortland CementHydrated OPCCaCO3Ca(OH)2MgCO3MgOMg(OH)2
97 John Harrison Presentation AASMIC Conference Global AbatementWithout CO2 Capture during manufacture (billion tonnes)With CO2 Capture during manufacture (billion tonnes)Total Portland Cement Produced Globally1.80Global mass of Concrete (assuming a proportion of 15 mass% cement)12.00Global CO2 Emissions from Portland Cement3.60Mass of Eco-Cement assuming an 80% Substitution in global concrete use9.60Resulting Abatement of Portland Cement CO2 Emissions2.88CO2 Emissions released by Eco-Cement2.591.34Resulting Abatement of CO2 emissions by Substituting Eco-Cement0.291.53
98 Abatement from Substitution John Harrison Presentation AASMIC ConferenceAbatement from SubstitutionBuilding Material to be substitutedRealistic % Subst-itution by TecEco technologySize of World Market (million tonnesSubstituted Mass (million tonnes)CO2 Factors (1)Emission From Material Before SubstitutionEmission/Sequestration from Substituted Eco-Cement (Tonne for Tonne Substitution Assumed)Net AbatementEmissions - No CaptureEmissions - CO2 CaptureAbatement - No CaptureAbatement CO2 CaptureBricks85%250212.50.2859.5126.96.36.1999.8Steel25%8402102.38499.856.629.4443.2470.4Aluminium20%20.54.118.073.81.10.672.773.2TOTAL426.620.7633.1114.959.7518.2573.4Concretes already have low lifetime energies.If embodied energies are improved could substitution mean greater market share?Figures are in millions of Tonnes