The Properties of Magnesia - Portland Cement - Pozzolan Blends
Transcript of The Properties of Magnesia - Portland Cement - Pozzolan Blends
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New Binders Based on the Addition of ReactiveMagnesia to Hydraulic Cements With or Without
Added Pozzolan.
All I ask is that the industry think about what I am saying.
John Harrison B.Sc. B.Ec. FCPA.
Hobart, Tasmania, Australia
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Construction Industry MineralsVitrified and calcined minerals and their derivatives are the main
materials used to construct the built environment which is our footprint on earth. Globally over 3 billion tonnes of calcined minerals (cement, lime and
magnesia) are produced annually. Global Portland cementproduction is in the order of 1.8 billion tonnes. The largest producersof Portland cement are China at over 500 million tonnes followed byIndia at over 109 million tonnes. The figures for vitrified clays are
substantial but unknown.TecEco estimate that buildings and infrastructure account forover 60% of anthropogenic materials flows.The built environment represents a huge opportunity forsustainability. Greater durability Lower embodied and lifetime energies Waste utilisation and recycling Abatement and better still - sequestration
TecEco technologyaddresssustainability issuesin a holistic way
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Sustainability IssuesCalcined mineral materials and their derivatives used inconstruction such as Portland cement, lime and magnesiaare made from carbonates.The process of calcination involves driving off chemicallybound CO 2 with heat.
MCO 3 MO CO 2
Fuel oil, coal, natural gas or other fuels are directly orindirectly burned to produce the energy required forvitrification of clays and producing calcined materialsreleasing CO 2 .
The production of vitrified and calcined mineral materialsaccounts for around 12% -15% of global anthropogenic CO 2 .
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Talked about Rheology
Time for and method of placing and finishing Shrinkage
Cracking, crack control Durability and Performance
Sulphate and chloride resistance Carbonation Corrosion of steel and other reinforcing Bonding to brick and tiles Alkali aggregate reactions Delayed reactions (eg ettringite)
EfflorescenceRarely discussed Sustainability
Emissions and embodied energies
Should thediscussion bemore abouthow we couldfix thematerial,
overcomingrather thantolerating andmitigatingtheseproblems?
Materials Science Issues with OPC Concrete
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Conclusions?Sustainability can be improved with improved performance(eg.durability) and emissions reductions (lower embodiedenergies).Cementitous calcined mineral materials or compositesincluding OPC concretes offer more scope for sustainabilitythan vitrified minerals.Portlandite is the main problem with Portland cement. Better to fundamentally fix the material than continue with what amount to band
aid fixes. The merits of removing and replacing Portlandite with another less soluble, easily
manufactured alkali should be considered.
Technology improvements increase market share and fueleconomic growth Carbon trading and regulations will favour adoption of better technologies.
The TecEco technology is an opportunity to betaken not a threat to be ignored!
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Partially hydrated Portland cement paste [Soroos,1999 ].
The
consequences ofremovingPortlandite (lime)with thepozzolanicreaction and fillingthe voids betweenhydrating cementgrains withbrucite , aninsoluble alkalinemineral, need tobe considered.
The important thing in science is not so much to obtain newfacts as to discover new ways of thinking about them.
-- Sir William Bragg
TecEco Technology - Simple Yet Ingenious?
Glue as well as Velcro?
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TecEco Cements A Blending System
TecEco cements are a system of blending reactivemagnesia, Portland cement and usually a pozzolan
Imagination is moreimportant than
knowledge,knowledge islimited.
Albert Einstein
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TecEco Cement SummaryTwo main formulation strategies so far: TecEco modified Portland cements (eg 10% MgO, 90%
OPC.) Contain more Portland cement than reactive magnesia
Reactive magnesia hydrates in the same rate order as Portland cementforming brucite which densifies, maintains a lower long term pH and dueto its low solubility, mobility and reactivity results in greater durability.
Other benefits include improvements in rheology, the use of a widerrange of aggregates and possibly no shrinkage
TecEco eco-cements (eg 50-75% MgO, 50-25% OPC) Contain more reactive magnesia than Portland cement
Brucite in porous materials eventually carbonates Forming stronger fibrous minerals. Resulting in huge opportunities for abatement.
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Reactivity Overcomes Delayed Hydration Problems.
Delayed hydration leads to dimensional distress. Magnesium was banned in Portland cements because when it goes through
the high temperature process of making Portland cement it becomes periclase.It is dead burned, hydrates slowly and causes dimensional distress.
Dead burned lime is much more expansive than dead burned magnesia(1), aproblem largely forgotten about by cement chemists.
The reactivity of magnesia is a function of the state of disorder,
specific surface area and glass forming impurities. The state of disorder is dependent on the temperature of calcining and probably
the most important, followed by the level of impurities such as iron. Make a particle small enough and it will react with just about anything
A new patented TecEco kiln technology which combines calciningand grinding should make it possible to calcine at lower
temperatures and produce more reactive magnesia with reducedproblems due to impurities as well as capture CO 2 .
(1) Ramachandran V. S., Concrete Science, Heydon & Son Ltd. 1981, p 358-360.
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Why Replace Portlandite with Brucite?
Portlandite is reactive, carbonates readily and being solublecan act as an electrolyte. TecEco remove Portlandite inreactions with Pozzolans.TecEco replace Portlandite with brucite which is much lesssoluble, mobile and reactive, does not act as an electrolyte orcarbonate as readily. Improving the rheology Using up bleed water as it hydrates Filling in the pores, increasing the density Sealing off the atmosphere
Providing long term pH control with many consequencesincluding greater durability.
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Ramifications of Adding Reactive Magnesia (1)
A low er more S tab le Long Term pH?: As Portlandite isremoved the pH becomes governed by the solubility of bruciteand is much lower at around 10.5 -11, allowing a wider rangeof aggregates to be used without AAR problems. Carbonationis slower and the pH remains high enough to keep Fe FeO andFe
3O
4 stable for much longer.
Durabi l i ty : TecEco modified Portland cements are denser,protected by brucite, are not attacked by salts, do notcarbonate readily and last indefinitely.Easy to Us e: With improved homogeneity and rheology. Fine
magnesia acts as a lubricant for Portland cement.
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Ramifications of Adding Reactive Magnesia (2)
Greater Densi ty , redu ced perm eabi l i ty? : Brucite fills porespaces taking up mix and bleed water as it hydrates reducingvoids and shrinkage. (brucite is 58.3 mass% water!)Greater St reng th? Less sh r ink age?: A lower water cementratio could mean greater strength and in the right propotion,no shrinkage.More Su sta inable: TecEco cements and eco-cements use ahigh proportion of recycled materials, immobilise toxic andhazardous wastes, can use a wider range of aggregates
reducing transport emissions and have superior durability.Eco-cements reabsorb chemically released CO 2.
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Ramifications of Adding Reactive Magnesia (3)
Ins ula t ing Pro per t ies / High Therm al Mass / Lo wEmbo died Energy: Eco-cement products will be favoured forenergy conserving buildings.Recyclable: Eco-cement products can be reprocessed andreused, making them more attractive to many users.
A Fire Retardan t: Brucite and magnesite are both fireretardants. TecEco cement products put fires out by releasingCO 2 at relatively low temperaturesLo w Capi ta l Cost : No new plant and equipment is required.
Lo w er Mater ia ls Cost : With economies of scale TecEcocements should be cheaper.
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Durability - A Lower More Stable Long Term pH
Eh pH orPourbaixDiagram Thestabilityfields ofiron in thepresenceof oxygenand carbondioxide. Source:Krauskopf K. B.,Introduction toGeochemistry,McGraw HillBook Company,1967, page 168,after Garrels &Christ (1965),
page 224.
TecEcoCementzone.
Long term pH is governed
by the solubility of bruciteand is much lower at around10.5 -11, allowing a widerrange of aggregates to beused, reducing problemssuch as AAR and etching,
but still high enough to keepFe and Fe 3O 4 stable. As thehydroxides of most heavymetals are also least solubleat around pH 10.5 11,TecEco cements aresuitable for toxic andhazardous wasteimmobilisation.
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Durability Reduced Delayed Reactions
A wide range of delayed reactions can occur in Portlandcement based concretes such as delayed alkali silicaand alkali carbonate reactions, the delayed formation ofettringite and thaumasite, delayed hydration of minerals
such as dead burned lime and magnesia.Delayed reactions are reduced in TecEco modifiedPortland cement concretes because: The hydration of magnesia consumes water drying concrete
from the inside out. Reactions occur very slowly by diffusion. A lower long term pH results in reduced reactivity. Potentially reactive ions are trapped in the structure of brucite.
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Durability Rapidly Reduced Pore Water
Ordinary Portland cement concretes can take years todry out. The presence of water allows reactions to occur much more
rapidly than by diffusion.
Reactive magnesia consumes water on hydration
resulting in more rapid onset of a water deficit.Delayed reactions such as: Hydration of dead or hard burned magnesia. The formation of alkali aggregate reaction products. Chlorides, sulphates and carbonates Ettringite and thaumasite.
Are therefore likely to be minimised.
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Durabiliy - Reduced Steel CorrosionA pH of over 8.9 is maintained formuch longer and steel remainspassive.Brucite does not react readilyresulting in reduced carbonationrates and reactions with salts.
Concrete with brucite is denser andcarbonation is expansive, sealingthe surface preventing furtheraccess by moisture, CO 2 and salts.Brucite is less soluble and trapssalts as it forms resulting in lessionic transport to complete acircuit for electrolysis and lesscorrosion.
Anode
Cathode
Ionic transport
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Brucite has always played a protective roleduring salt attack. Putting it in the matrix ofconcretes in the first place makes sense.Brucite does not react with salts becauseof its low solubility (reactivity, mobility) andlower pH (reactivity) Ksp brucite = 1.8 X 10 -11 Ksp Portlandite = 5.5 X 10 -6 Carbonation of brucite is slow G or Brucite = -19.55 G or Portlandite = -64.62
Durability - Reduced Salt Attack and Carbonation
5 orders of magnitude
3 orders of magnitude
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Durability - Increased DensityOn hydration magnesiaexpands 116.9 % fillingvoids and surroundinghydrating cement grains.Brucite is 58.3 % water.Lower water cement ratiosresult in greater density.Greater density results ingreater strength, moredurable concrete with ahigher salt resistance andless corrosion of steel etc.
Picture Courtesy Applied Petrographic Services NSW Aust.
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Durability Reduced Permeability
As bleed water exits ordinary Portland cementconcretes it creates an interconnected pore stucturethat remains in concrete allowing the entry of aggressiveagents such as SO 4--, Cl - and CO 2TecEco modified Portland cement concretes do not
bleed they tend to dry from within.In TecEco modified Portland cement concretes mixwater is used up in the hydration of reactive magnesia
forming brucite
TecEco modified Portland cement concretes are denserand less permeable even to vapours
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Strength - Enhanced Pozzolanic Reactions?With small substitutions by reactive magnesia for OPC it
is likely that the early stage pH during the plastic stageof concrete setting is actually higher due tosupersaturation cause by the additional removal ofwater by magnesia as it hydrates.If there is an early high pH then the pozzolanic and othersilicification reactions should ensue more readily.
13.7
pH
Time
10.4 TecEco Modifified OPC Concretewith 10% reactive ma nesia
OPC Concrete
HYPOTHETICAL PH CURVESOVER TIME
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Strength A lower Water Cement Ratio?
TecEco modified Portland cement concretes haveexcellent rheology resulting in a lower water cementratio.There is a linear correlation between the water cement
ratio and strength.Lower water cement ratios result in greater strength.Water is also removed by brucite as it hydratesincreasing the density.
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Safety Reduced Fire Damage
The main phase in TecEco modified ordinary Portlandcement concretes is brucite.The main phases in TecEco eco-cements are magnesiteand hydromagnesite.Brucite, magnesite and hydromagnesite are excellent
fire retardants and extinquishers.At relatively low temperatures Brucite releases water and reverts to magnesium oxide. Magnesite releases CO2 and converts to magnesium oxide. Hydromagnesite releases CO2 and water and converts to
magnesium oxide.Fires are therefore not nearly as aggressive resulting inless damage to structures.
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Improved RheologySuitable reactive magnesia is much finer than most other
cements such as Portland cement and carries what wesuspect is a high positive surface charge.Finely ground reactive magnesia therefore acts as aplasticiser. Improving rheology
Lower water cement ratio results in greater strength and reducedporosity.
The proportion and cost of binders and plasticisers can bereduced.
Second layer low slump TecEcomodified Portland cement concreteTech Tendons
First layer low slump TecEcomodified Portland cement concrete
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Reasons for Improved Rheology
There are also surface charge affects andwater reducing agents are not required.Reactive Magnesia is a plasticiser as well.
Reactive Magnesiagrains Mean size 6 -10 micron
Portland cement grainsMean size 20 - 60micron
The magnesiagrains act as ball
bearings to thePortland cementgrains and also fillthe voids densifyingthe whole
Smaller grains (egmicrosilica) for evenbetter rheology.
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Potential for Neutral Cure Modified Portland Cement Concretes
90 days28
??
? ?
?
??
?
-.05%
+.05%
Portland Cement
Reactive Magnesia
Composite Curve
+- Fly Ash?
HYDRATION THEN CARBONATION OF REACTIVE MAGNESIA AND OPC
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Volume Changes with TecEco Modified PortlandCements on Carbonation
Consider what happens when Portlandite carbonates:Ca(OH) 2 + CO 2 CaCO 374.08 + 44.01 100 molar mass 33.22 + gas 28.10 molar volumes
18.22% shrinkage
Surface shrinkage causing cracks to appear.Compared to brucite forming magnesite as it carbonates:
Mg(OH) 2 + CO 2 MgCO 358.31 + 44.01 84.32 molar mass 24.29 + gas 28.10 molar volumes
15.68% expansion Slight expansion and densification of the surface preventing further
ingress of CO 2 and carbonation.
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TecEco Eco-Cements - Solving Waste ProblemsThe best thing to do with wastes is if at all possible
to use them. If they cannot directly be usedthen they have to be immobilised.TecEco cements are ideal for immobilising /utilising toxic and hazardous wastes such as flyand bottom ash, iron slags, red mud etc.:
They are more durable. Brucite results in an ideal long term equilibrium pH of 10.5
11 at which most heavy metal hydroxides are relativelyinsoluble.
The OPC in TecEco cements takes up lead.
Homogenous and do not bleed water Not attacked by salts in ground or sea water. Dimensionally more stable with less cracking.
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Toxic and Hazardous Waste Immobilisation
The brucite in TecEcocements has astructure comprisingelectronically neutrallayers and is able toaccommodate a wide
variety of extraneoussubstances betweenthe layers and cationsof similar sizesubstituting formagnesium within the
layers and is known tobe very suitable fortoxic and hazardouswaste immobilisation.
Layers of
electronicallyneutral brucitesuitable fortrappingbalancedcations andanions as well
as othersubstances Salts andother toxicandhazardoussubstancesbetweenlayers
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Sustainability=Abatement=Lower Cost
TecEco cements generally A high proportion of brucite compared to Portlandite is water and of
magnesite compared to calcite is CO 2. Every mass unit of TecEco cements therefore produces a greater volume of
built environment than Portland and other calcium based cements. Lessneed therefore be used reducing costs/energy/emissions.
Improved durability and other properties results in lower long run
costs/energies/emissions due to less frequent replacement. Brucite is less soluble, mobile or reactive than Portlandite and not attacked
by salts. The pH is lower but more stable resulting in less AAR, etching and other
problems but still high enough for longer, maintaining the passivity of steelfor longer.
TecEco eco-cements Carbon dioxide is also reabsorbed by brucite from the atmosphere. Afree resource resulting in carbon sequestration and carbon credits.
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Sustainability=Abatement=Lower Cost (2)Energy costs money and results in emissions and is the largest cost
factor in the production of mineral binders. Whether more or less energy is required for the manufacture of reactive
magnesia compared to Portland cement or lime depends on the stage in theutility adding process.
Volume of built material has greater utility and is more validly compared. The new TecEco kiln technology will result in around 25% less energy being
required and the capture of CO 2 during production resulting in lower costs and
carbon credits.A wider range of aggregates can be utilised without problemsreducing transport and other costs/energies/emissions.The manufacture of reactive magnesia is a benign process that canbe achieved with waste or intermittently available energy.Because reactive magnesia is also an excellent plasticiser, other
costly additives are not required for this purpose.Eco-cement products absorb CO 2 , utilise wastes and can to a certainextent be recycled.
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Basic Chemical Reactions
Notice thelowsolubility ofbrucitecomparedtoPortlandite
and thatmagnesiteis strongerand adoptsa moreideal habitthan calcite& aragonite
Magnesia Brucite
MgO + H 2O Mg(OH) 2
Hardness: 2.5 - 3.0 4.0 3.5
Form: Massive-Sometimes Fibrous Often Fibrous Acicular - Needle-like crystals
Solubility (mol.L -1): .00015 .0013 .0011
Silicates and aluminosilicates
Magnesia Brucite Magnesite Hydromagnesite
MgO + H 2O Mg(OH) 2 + CO 2 MgCO 3 + Mg(OH) 2.4MgO.4CO 2.4H 2O
In Eco - Cements
In TecEco Modified Portland Cements
Hardness: 2.5-3.00 3.0
Form: Massive Massive or crystalline More acicular
Solubility (mol.L -1): .024 .00014
Portlandite Calcite
Ca(OH) 2 + CO 2 CaCO 3
Compare to Portlandite
Aragonite
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The Magnesium Thermodynamic Cycle
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Manufacture of Portland Cement
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Specific Comments Regarding Problems in India
The lower long term pH of TecEco cements means that a widerrange of aggregates can be tolerated without problems. Many problems appear to be due to the failure of contractors to adhere
to reasonable standards, compromising particularly with aggregates.
TecEco cements result in better renders, gunnites and othermortars. Good rheology, white colour, less efflorescence and a better bond to
concrete and tiles (Tile de-bonding appears common)
Greater durability A lower pore water ionic concentration should result in less corrosion of
steel reinforcement and pipes.
Lower pollution, greater sustainability Replacement of topsoil clay bricks etc. with less polluting, excellent
quality bricks, blocks and pavers made substantially with wastes.
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The TecEco Challenge
Although the technology is new and not yet fullycharacterised, TecEco challenge universities andconstruction authorities to come to grips with the newcement technology and quantify performance incomparison to ordinary Portland cement and othercompeting materials.TecEco will do its best to assist. Negotiations are underway in many countries toorganise supplies to allow such scientific endeavour toproceed.TecEco technologies are an opportunity not a threat.
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TecEco Technology SummarySimple, smart and sustainable? TecEco cement technology has resulted in potential solutions to a
number of problems with Portland and other cements includingdurability and corrosion, the alkali aggregate reaction problem andthe immobilisation of many problem wastes and will provides arange 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 andsocial outcomes.
Climate Change Pollution
Durability Corrosion
ASR Rheology
Shrinkage Placement , Finishing
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Addressing Issues in Concrete ScienceAddressing the research objectives of concrete science.
Durability salt resistance and steel corrosion may become problemsof the past. Lower use of materials and energy
over time saving money and the environment. Lower more stable long term alkalinity.
Reduced AAR and steel corrosion etc. Better rheology.
Lower water cement ratio, less shrinkage, and easier placement.
Other improved properties: Greater density, adjustable placing and finishing times. Fire retarding properties
Lower Costs Making reactive magnesia is a benign process with potential for using waste
energy and capture of CO 2. A wider range of aggregates including wastes will be available
reducing cartage costs and emissions. Water or CO
2 from the air comprise a high mass % and volume % of the
magnesium minerals in TecEco cements. Water and CO 2 are free or attractcarbon credits
Expensive plasticisers are not required
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TecEcos Immediate Focus Form strategic alliances with major companies.Raise money for Research Around 1 millions dollars worth in thepipeline.Concentrate on defined markets for low technical risk products thatrequire minimal research and development and for whichperformance based standards apply. Carbonated products such as bricks, blocks, stabilised earth blocks,
pavers, roof tiles pavement and mortars that utilise large quantities ofwaste and products where sustainability, rheology or fire retardationare an issue. (Mainly eco-cement technology using fly ash).
The immobilisation of wastes including toxic hazardous and otherwastes because of the superior performance of the technology andthe rapid growth of markets. (Eco-cements and modified Portlandcements).
Products such as renders and mortars where excellent rheology andbond strength are required.
Products where extreme durability is required. Products for which weight is an issue.
Continue our awareness campaign regarding TecEco cements, thenew TecEco kiln design and the Tech Tendon method ofprestressing, partial prestressing and reinforcing.
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TecEco Minding the FutureTecEco are aware of the enormous weight of
opinion necessary before standards can bechanged globally for TecEco modified cementconcretes for general use. TecEco already have a number of institutions and universities
around the world doing research.
TecEco have received huge global publicity not all ofwhich is correct and have therefore publicly released thetechnology. TecEco research documents are available from TecEco by request.
Soon they will be able to be purchased from the web site.
Other documents by other researchers will be made available in asimilar manner as they become available.Technology standing on its own is not inherently good. It stillmatters whether it is operating from the right value system andwhether it is properly available to all people.
-- William Jefferson Clinton
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TecEco Eco - Cements for Sustainable Cities
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Manufacture of Eco-Cement Products
CausticMagnesiaCalcinedusing wasteheat and/orsustainableenergy
Flyash
Other ingredientsEco-MasonryProductse.g. Bricks& blocks
Hydration using fluecooling &/orscrubbing water &flue steam.Carbonation usingwarm CO 2 richgases
Coal
Combustion
TecEco - Cements
MagnesiteCoal
Bottom ash &other wastesas aggregates
Eco-Cement One of ManyPossible Manufacturing Scenarios
PortlandCement
CO2
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TecEco Kiln TechnologyRemember:The reactivity of most calcined materials including magnesiais a function of the state of disorder, specific surface areaand glass forming impurities.
What if calcining and grinding occurred at the
same time? Heat would literally be squashed into the material to be
calcined, reducing the risk of overburning. The clastic conditions should increase the state of disorder and
reduce the formation of glasses resulting in greater reactivity. CO 2 could be captured at source. The heat lost through grinding could be used for calcining
resulting in around 25% greater efficiency.
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Energy On a Mass Basis
Relative toRaw MaterialUsed tomakeCement
FromManufactur ingProcessEnergyRelease100%Efficient(Mj.tonne -1)
FromManufacturing ProcessEnergyRelease withInefficiencies (Mj.tonne -1)
RelativeProductUsed inCement
FromManufacturing ProcessEnergyRelease100%Efficient(Mj.tonne -1)
FromManufacturing ProcessEnergyRelease withInefficiencies(Mj.tonne -1)
Relative toMineralResultingin Cement
FromManufacturing ProcessEnergyRelease100%Efficient(Mj.tonne -1)
FromManufacturing ProcessEnergyReleasewithInefficiencies(Mj.tonne -1)
CaCO 3 +Clay 1545.73 2828.69
PortlandCement 1807 3306.81
HydratedOPC 1264.90 2314.77
CaCO 3 1786.09 2679.14 Ca(OH) 2 2413.20 3619.80
MgCO 3 1402.75 1753.44 MgO 2934.26 3667.82 Mg(OH) 2 2028.47 2535.59
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Energy On a Volume Basis
Relativeto RawMaterialUsed tomakeCement
FromManufacturing ProcessEnergyRelease100%Efficient(Mj.metre -3)
FromManufacturing ProcessEnergyRelease withInefficiencies(Mj.metre -3)
RelativeProductUsed inCement
FromManufactur ingProcessEnergyRelease100%Efficient(Mj.metre -3)
FromManufacturing ProcessEnergyRelease withInefficiencies(Mj.metre -3)
Relative toMineralResultingin Cement
FromManufactur ingProcessEnergyRelease100%Efficient(Mj.metre -3)
FromManufacturingProcessEnergyRelease withInefficiencies(Mj.metre -3)
CaCO 3 + Clay 4188.93 7665.75
PortlandCement 5692.05 10416.45
HydratedOPC 3389.93 6203.58
CaCO 3 6286.62 8429.93 Ca(OH) 2 5381.44 8072.16
MgCO 3 4278.39 5347.99 MgO 9389.63 11734.04 Mg(OH) 2 4838.32 6085.41
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Abatement TecEco Eco-Cements
Eco-cements inporous productsabsorb carbondioxide from theatmosphere.Brucitecarbonatesforminghydromagnesiteand magnesite,completing thethermodynamiccycle.
No Capture11.25% mass%reactive magnesia,3.75 mass%Portland cement, 85mass% aggregate.
Emissions
.37 tonnes to thetonne. Aftercarbonation.approximately .241tonne to the tonne.
PortlandCements15 mass% Portlandcement, 85 mass%aggregate
Emissions
.32 tonnes to thetonne. Aftercarbonation.
Approximately .299tonne to the tonne.
Greater Sustainability.299 > .241 >.140 >.113Bricks, blocks, pavers, mortars and pavement made using eco-cement, fly and bottom ash (with capture of CO 2 duringmanufacture of reactive magnesia) have 2.65 times less emissionsthan if they were made with Portland cement.
Capture CO 2 11.25% mass%reactive magnesia,3.75 mass% Portlandcement, 85 mass%aggregate.
Emissions
.25 tonnes to thetonne. Aftercarbonation.approximately .140tonne to the tonne.
Capture CO 2.Fly and Bottom
Ash11.25% mass% reactivemagnesia, 3.75 mass%Portland cement, 85
mass% aggregate.
Emissions
.126 tonnes to the tonne. After carbonation. Approximately .113 tonneto the tonne.
On the basis of the volume of building materials
produced the figures are even better!
85 wt% Aggregates
15 wt%Cement
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Global AbatementWithout CO2
Capture duringmanufacture(billion tonnes)
With CO2
Capture duringmanufacture(billion tonnes)
Total Portland Cement Produced Globally 1.80 1.80
Global mass of Concrete (assuming aproportion of 15 mass% cement)
12.00 12.00
Global CO 2 Emissions from Portland Cement 3.60 3.60
Mass of Eco-Cement assuming an 80%Substitution in global concrete use
9.60 9.60
Resulting Abatement of Portland Cement CO 2 Emissions
2.88 2.88
CO 2 Emissions released by Eco-Cement 2.59 1.34Resulting Abatement of CO 2 emissions bySubstituting Eco-Cement
0.29 1.53
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Abatement from Substitution
Figures are in millions of Tonnes
BuildingMaterial to be
substituted
Realistic %
Subst-itutionbyTecEcotechnology
Size ofWorld
Market(milliontonnes
Substituted
Mass(milliontonnes)
CO2Fact
ors(1)
EmissionFrom
MaterialBeforeSubstitution
Emission/Sequestration from Substituted
Eco-Cement (Tonnefor TonneSubstitutionAssumed)
Net Abatement
Emissions - NoCapture
Emissions - CO2Capture
Abatement - NoCapture
AbatementCO2Capture
Bricks 85% 250 212.5 0.28 59.5 57.2 29.7 2.3 29.8
Steel 25% 840 210 2.38 499.8 56.6 29.4 443.2 470.4
Aluminium 20% 20.5 4.1 18.0 73.8 1.1 0.6 72.7 73.2
TOTAL 426.6 20.7 633.1 114.9 59.7 518.2 573.4
Concretes already have low lifetime energies.
If embodied energies are improved couldsubstitution mean greater market share?
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TecEco Movie Theatre
Discovery Channel Movieon Eco-Cements
Shown courtesy Discovery Channel Canada
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???
Autogenous healingCoatings a good or a bad thing?