all i ask is that the industry think about what i am saying. john harrison b.sc. b.ec. fcpa

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New Binders Based on the Addition of Reactive Magnesia to Hydraulic Cements With or Without

Added Pozzolan.

New Binders Based on the Addition of Reactive Magnesia 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 MineralsConstruction Industry Minerals Vitrified 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 cement production is in the order of 1.8 billion tonnes. The largest producers of Portland cement are China at over 500 million tonnes followed by India at over 109 million tonnes. The figures for vitrified clays are substantial but unknown.

TecEco estimate that buildings and infrastructure account for over 60% of anthropogenic materials flows.

The built environment represents a huge opportunity for sustainability.– Greater durability– Lower embodied and lifetime energies– Waste utilisation and recycling– Abatement and better still - sequestration

TecEco technology address sustainability issues in a holistic way

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Sustainability IssuesSustainability Issues Calcined mineral materials and their derivatives used in

construction such as Portland cement, lime and magnesia are made from carbonates.

The process of calcination involves driving off chemically bound CO2 with heat.

MCO3 →MO + CO2 ∆

Fuel oil, coal, natural gas or other fuels are directly or indirectly burned to produce the energy required for vitrification of clays and producing calcined materials releasing CO2.

The production of vitrified and calcined mineral materials accounts for around 12% -15% of global anthropogenic CO2.

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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)• Efflorescence

Rarely discussed– Sustainability

• Emissions and embodied energies

Should the discussion be more about how we could fix the material, overcoming rather than tolerating and mitigating these problems?

Materials Science Issues with OPC ConcreteMaterials Science Issues with OPC Concrete

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Conclusions?Conclusions? Sustainability can be improved with improved performance

(eg.durability) and emissions reductions (lower embodied energies).

Cementitous calcined mineral materials or composites including OPC concretes offer more scope for sustainability than 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 fuel economic growth

– Carbon trading and regulations will favour adoption of better technologies.

The TecEco technology is an opportunity to be taken not a threat to be ignored!

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Partially hydrated Portland cement paste [Soroos,1999 ].

The consequences of removing Portlandite (lime) with the pozzolanic reaction and filling the voids between hydrating cement grains with brucite, an insoluble alkaline mineral, need to be considered.The important thing in science is not so much to

obtain new facts as to discover new ways of thinking about them. -- Sir William Bragg

TecEco Technology - Simple Yet Ingenious?TecEco Technology - Simple Yet Ingenious?

Glue as well as Velcro?

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TecEco Cements – A Blending SystemTecEco Cements – A Blending System

TecEco cements are a system of blending reactive magnesia, Portland cement and usually a pozzolan

Imagination is more important than knowledge, knowledge is limited.

Albert Einstein

SUSTAINABILITY

DURABILITY STRENGTH TECECO MODIFIED PORTLAND CEMENTS AND ECO-CEMENTS

HYDRAULIC CEMENT e.g. PORTLAND

POZZOLAN

REACTIVE MAGNESIA

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TecEco Cement SummaryTecEco Cement Summary Two 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 cement

forming brucite which densifies, maintains a lower long term pH and due to it’s low solubility, mobility and reactivity results in greater durability.

– Other benefits include improvements in rheology, the use of a wider range 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.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), a problem 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 calcining

and grinding should make it possible to calcine at lower temperatures and produce more reactive magnesia with reduced problems due to impurities as well as capture CO2.

(1) Ramachandran V. S., Concrete Science, Heydon & Son Ltd. 1981, p 358-360.

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Why Replace Portlandite with Brucite?Why Replace Portlandite with Brucite?

Portlandite is reactive, carbonates readily and being soluble can act as an electrolyte. TecEco remove Portlandite in reactions with Pozzolans.

TecEco replace Portlandite with brucite which is much less soluble, mobile and reactive, does not act as an electrolyte or carbonate 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 consequences

including greater durability.

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Ramifications of Adding Reactive Magnesia (1)Ramifications of Adding Reactive Magnesia (1)

A lower more Stable Long Term pH?: As Portlandite is removed the pH becomes governed by the solubility of brucite and is much lower at around 10.5 -11, allowing a wider range of aggregates to be used without AAR problems. Carbonation is slower and the pH remains high enough to keep Fe FeO and Fe3O4 stable for much longer.

Durability: TecEco modified Portland cements are denser, protected by brucite, are not attacked by salts, do not carbonate readily and last indefinitely.

Easy to Use: With improved homogeneity and rheology. Fine magnesia acts as a lubricant for Portland cement.

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Greater Density, reduced permeability?: Brucite fills pore spaces taking up mix and bleed water as it hydrates reducing voids and shrinkage. (brucite is 58.3 mass% water!)

Greater Strength? Less shrinkage?: A lower water cement ratio could mean greater strength and in the right propotion, no shrinkage.

More Sustainable: TecEco cements and eco-cements use a high proportion of recycled materials, immobilise toxic and hazardous wastes, can use a wider range of aggregates reducing transport emissions and have superior durability. Eco-cements reabsorb chemically released CO2.

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Insulating Properties / High Thermal Mass / Low Embodied Energy: Eco-cement products will be favoured for energy conserving buildings.

Recyclable: Eco-cement products can be reprocessed and reused, making them more attractive to many users.

A Fire Retardant: Brucite and magnesite are both fire retardants. TecEco cement products put fires out by releasing CO2 at relatively low temperatures

Low Capital Cost: No new plant and equipment is required. Lower Materials Cost: With economies of scale TecEco

cements should be cheaper.

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Durability - A Lower More Stable Long Term pHDurability - A Lower More Stable Long Term pH

Eh-pH or Pourbaix Diagram The stability fields of iron in the presence of oxygen and carbon dioxide.Source: Krauskopf K. B., Introduction to Geochemistry, McGraw Hill Book Company, 1967, page 168, after Garrels & Christ (1965), page 224.

TecEco Cement zone.

Long term pH is governed by the solubility of brucite and is much lower at around 10.5 -11, allowing a wider range of aggregates to be used, reducing problems such as AAR and etching, but still high enough to keep Fe and Fe3O4 stable. As the hydroxides of most heavy metals are also least soluble at around pH 10.5 – 11, TecEco cements are suitable for toxic and hazardous waste immobilisation.

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Durability – Reduced Delayed ReactionsDurability – Reduced Delayed Reactions

A wide range of delayed reactions can occur in Portland cement based concretes such as delayed alkali silica and alkali carbonate reactions, the delayed formation of ettringite and thaumasite, delayed hydration of minerals such as dead burned lime and magnesia.

Delayed reactions are reduced in TecEco modified Portland 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 WaterDurability – Rapidly Reduced Pore Water Ordinary Portland cement concretes can take years to

dry 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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Durability – Increased Acid ResistanceDurability – Increased Acid Resistance

Carbonates are stable phases of both calcium and magnesium.

The Portlandite in Portland cement concretes carbonates at the surface resulting in a lower pH.

The addition of reactive magnesia in a TecEco modified Portland cement concrete results in reduced carbonation due to a lower carbonation rate and surface tightening due to expansion.

Magnesium carbonates that form at the surface of TecEco modified Portland cement concretes are more acid resistant.

Eco-cements are also more acid resistant as the main magnesium phase is magnesium carbonate.

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Durabiliy - Reduced Steel CorrosionDurabiliy - Reduced Steel Corrosion A pH of over 8.9 is maintained for

much longer and steel remains passive.

Brucite does not react readily resulting in reduced carbonation rates and reactions with salts.

Concrete with brucite 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.

Anode

Cathode

Ionic transport

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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 of it’s low solubility (reactivity, mobility) and lower pH (reactivity)– Ksp brucite = 1.8 X 10-11 – Ksp Portlandite = 5.5 X 10-6

Carbonation of brucite is slow Gor Brucite = -19.55 Gor Portlandite = -64.62

Durability - Reduced Salt Attack and CarbonationDurability - Reduced Salt Attack and Carbonation

5 orders of magnitude

3 orders of magnitude

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Durability - Increased DensityDurability - Increased Density On hydration magnesia

expands 116.9 % filling voids and surrounding hydrating cement grains.

Brucite is 58.3 % water. Lower water cement ratios

result in greater density. Greater density results in

greater strength, more durable concrete with a higher salt resistance and less corrosion of steel etc.

Picture Courtesy Applied Petrographic Services NSW Aust.

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Durability – Reduced PermeabilityDurability – Reduced Permeability

As bleed water exits ordinary Portland cement concretes it creates an interconnected pore stucture that remains in concrete allowing the entry of aggressive agents such as SO4

--, Cl- and CO2

TecEco modified Portland cement concretes do not bleed – they tend to dry from within.

In TecEco modified Portland cement concretes mix water is used up in the hydration of reactive magnesia forming brucite

TecEco modified Portland cement concretes are denser and less permeable even to vapours

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Strength - Enhanced Pozzolanic Reactions?Strength - Enhanced Pozzolanic Reactions? With small substitutions by reactive magnesia for OPC it

is likely that the early stage pH during the plastic stage of concrete setting is actually higher due to supersaturation cause by the additional removal of water by magnesia as it hydrates.

If there is an early high pH then the pozzolanic and other silicification reactions should ensue more readily.

13.7

pH

Time

10.4 TecEco Modifified OPC Concrete with 10% reactive magnesia

OPC Concrete

HYPOTHETICAL PH CURVES OVER TIME

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Strength – A lower Water Cement Ratio?Strength – A lower Water Cement Ratio?

TecEco modified Portland cement concretes have excellent rheology resulting in a lower water cement ratio.

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 hydrates

increasing the density.

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Safety – Reduced Fire DamageSafety – Reduced Fire Damage

The main phase in TecEco modified ordinary Portland cement concretes is brucite.

The main phases in TecEco eco-cements are magnesite and 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

in less damage to structures.

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Improved RheologyImproved Rheology Suitable reactive magnesia is much finer than most

other cements such as Portland cement and carries what we suspect is a high positive surface charge.

Finely ground reactive magnesia therefore acts as a plasticiser.– Improving rheology

– Lower water cement ratio results in greater strength and reduced porosity.

– The proportion and cost of binders and plasticisers can be reduced.

Second layer low slump TecEco modified Portland cement concrete

Tech Tendons

First layer low slump TecEco modified Portland cement concrete

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Reasons for Improved RheologyReasons for Improved Rheology

There are also surface charge affects and water reducing agents are not required. Reactive Magnesia is a plasticiser as well.

Reactive Magnesia grains Mean size 6 -10 micron

Portland cement grains Mean size 20 - 60 micron

The magnesia grains act as ball bearings to the Portland cement grains and also fill the voids densifying the whole

Smaller grains (eg microsilica) for even better rheology.

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Dimensionally Neutral TecEco Modified Portland Cement Concretes on Hydration?

Dimensionally Neutral TecEco Modified Portland Cement Concretes on Hydration?

Portland cement shrinks around .05%. Over the long term much more (>.1%).

When magnesia hydrates it expands: MgO (s) + H2O (l) ↔ Mg(OH)2 (s) 40.31 + 18.0 ↔ 58.3 molar mass 11.2 + liquid ↔ 24.3 molar volumes[1]

<=116.96 % expansion depending on whether the water is coming from mix water or bleed water from OPC.

• So far we have not observed shrinkage in TecEco modified Portland cement concretes (10% subst, OPC) also containing flyash.

• Could it be that the water lost by Portland cement as it shrinks is used by the reactive magnesia as it hydrates?

At some ratio, thought to be around 10% reactive magnesia and 90% OPC volume changes cancel each other out and setting and curing are close to neutral.

– More research is required for both modified Portland cements and eco-cements.[1] The molar volume (L.mol-1)is equal to the molar mass (g.mol-1) divided by the density (g.L-1).

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Potential for Neutral Cure Modified Portland Cement ConcretesPotential for Neutral Cure Modified Portland Cement Concretes

90 days 28

? ?

? ?

?

? ?

?

-.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 Portland Cements on Carbonation

Volume Changes with TecEco Modified Portland Cements on Carbonation

Consider what happens when Portlandite carbonates:Ca(OH)2 + CO2 CaCO3

74.08 + 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 + CO2 MgCO3

58.31 + 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 CO2 and carbonation.

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TecEco Eco-Cements - Solving Waste ProblemsTecEco Eco-Cements - Solving Waste Problems The 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 relatively insoluble.

– 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 ImmobilisationToxic and Hazardous Waste Immobilisation

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 toxic and hazardous substances between layers

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Sustainability=Abatement=Lower CostSustainability=Abatement=Lower Cost

TecEco cements generally– A high proportion of brucite compared to Portlandite is water and of

magnesite 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.

– 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 steel for longer.

TecEco eco-cements– Carbon dioxide is also reabsorbed by brucite from the atmosphere. A

free resource resulting in carbon sequestration and carbon credits.

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Sustainability=Abatement=Lower Cost (2)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 the utility 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 CO2 during production resulting in lower costs and carbon credits.

A wider range of aggregates can be utilised without problems reducing transport and other costs/energies/emissions.

The manufacture of reactive magnesia is a benign process that can be 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 CO2, utilise wastes and can to a certain extent be recycled.

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Basic Chemical ReactionsBasic Chemical Reactions

Notice the low solubility of brucite compared to Portlandite and that magnesite is stronger and adopts a more ideal habit than calcite & aragonite

Magnesia Brucite

MgO + H2O 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 + H2O Mg(OH)2 + CO2 MgCO3 + Mg(OH)2.4MgO.4CO2.4H2O

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 + CO2 CaCO3

Compare to Portlandite

Aragonite

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The Magnesium Thermodynamic CycleThe Magnesium Thermodynamic Cycle

CO2

Magnesite*

Magnesia Brucite*

An alkaline environment in which silicates form

Cementitious phases

Dolomite*

Ca++

Thermal decomposition MgCO3 MgO + CO2 ΔH = 118.28 kJ.mol-1 ΔG = 65.92 kJ.mol-1

Carbonation Mg(OH)2 + CO2 MgCO3 + H2O ΔH = -37.04 kJ.mol-1 ΔG = -19.55 kJ.mol-1

Hydration MgO + H2O Mg(OH)2 ΔH = -81.24 kJ.mol-1 ΔG = -35.74 kJ.mol-1

Reactive phase

TOTAL CALCINING ENERGY (Relative to MgCO3) Theoretical = 1480 kJ.Kg-1 With inefficiencies = 1948 kJ.Kg-1

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Manufacture of Portland CementManufacture of Portland Cement

CO2

Calcite and Aragonite

Quicklime Portlandite

Cementitious phases

Clay

OPC Tri calcium silicate hydrate ΔH = - 114 kJ.mol-1

+ Pozzolan

Tri calcium aluminate ΔH = - 362 kJ.mol-1 Calcium alumino ferrite

Di calcium silicate hydrate ΔH = - 43 kJ.mol-1

Rotary Kiln

Thermal decomposition CaCO3 CaO + CO2 ΔH = 178.77 kJ.mol-1 ΔG = 130.98 kJ.mol-1

Carbonation Ca(OH)2 + CO2 CaCO3 + H2O ΔH = - 69.58 kJ.mol-1 ΔG = - 64.62 kJ.mol-1

Hydration CaO + H2O Ca(OH)2 ΔH = -109.19 kJ.mol-1 ΔG = - 66.35 kJ.mol-1

Reactive phases

Portland Cement

SUMMARY

Limestone + Clay

Estimated* ΔH = 1807 kJ.kg-1 ΔG = 1287 kJ. kg-1

*Note the measure is relative to Kg as mixed molar amounts are used.

TOTAL CALCINING ENERGY. (Relative to CaCO3) Theoretical = 1807 kJ.Kg-1

With inefficiencies = 3306 kJ.Kg-1

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Specific Comments Regarding Problems in IndiaSpecific Comments Regarding Problems in India

The lower long term pH of TecEco cements means that a wider range 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 other mortars.– 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 ChallengeThe TecEco Challenge

Although the technology is new and not yet fully characterised, TecEco challenge universities and construction authorities to come to grips with the new cement technology and quantify performance in comparison to ordinary Portland cement and other competing materials.

TecEco will do it’s best to assist. Negotiations are underway in many countries to

organise supplies to allow such scientific endeavour to proceed.

TecEco technologies are an opportunity not a threat.

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TecEco Technology SummaryTecEco Technology Summary Simple, smart and sustainable?

– TecEco cement technology has resulted in potential solutions to a number of problems with Portland and other cements including durability and corrosion, the alkali aggregate reaction problem 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 Change Pollution

Durability Corrosion

ASR Rheology

Shrinkage Placement , Finishing

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Addressing Issues in Concrete ScienceAddressing Issues in Concrete Science Addressing the research objectives of concrete science.

– Durability salt resistance and steel corrosion may become problemsof the past.

• Lower use of materials and energyover 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 CO2.• A wider range of aggregates including wastes will be available

reducing cartage costs and emissions.• Water or CO2 from the air comprise a high mass % and volume % of the

magnesium minerals in TecEco cements. Water and CO2 are free or attract carbon credits

• Expensive plasticisers are not required

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TecEco’s Immediate FocusTecEco’s Immediate Focus Form strategic alliances with major companies. Raise money for Research – Around 1 millions dollars worth in the

pipeline. Concentrate on defined markets for low technical risk products

that require minimal research and development and for which performance based standards apply.

– Carbonated products such as bricks, blocks, stabilised earth blocks, pavers, roof tiles pavement and mortars that utilise large quantities of waste and products where sustainability, rheology or fire retardation are an issue. (Mainly eco-cement technology using fly ash).

– The immobilisation of wastes including toxic hazardous and other wastes because of the superior performance of the technology and the rapid growth of markets. (Eco-cements and modified Portland cements).

– Products such as renders and mortars where excellent rheology and bond strength are required.

– Products where extreme durability is required.– Products for which weight is an issue.

Continue our awareness campaign regarding TecEco cements, the new TecEco kiln design and the Tech Tendon method of prestressing, partial prestressing and reinforcing.

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TecEco Minding the FutureTecEco Minding the Future TecEco 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 of which is correct and have therefore publicly released the technology.– 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 a similar manner as they become available.

Technology standing on its own is not inherently good. It still matters whether it is operating from the right value system and whether it is properly available to all people.

-- William Jefferson Clinton

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TecEco Eco - Cements for Sustainable CitiesTecEco Eco - Cements for Sustainable Cities

RAW MATERIALS

RECYCLABLE MATERIALS

ECO-CEMENT PRODUCTS

MINING

RECYCLING CITIES

CO2

PERMANENT SEQUESTRATION (Man Made Carbonate Rock As A

Building Material)

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Manufacture of Eco-Cement ProductsManufacture of Eco-Cement Products

Caustic Magnesia Calcined using waste heat and/or sustainable energy

Flyash

Other ingredients Eco-Masonry Products e.g. Bricks & blocks

Hydration using flue cooling &/or scrubbing water & flue steam. Carbonation using warm CO2 rich gases

Coal Combustion

TecEco - Cements

Magnesite Coal

Bottom ash & other wastes as aggregates

Eco-Cement – One of Many Possible Manufacturing Scenarios

Portland Cement

CO2

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TecEco Kiln TechnologyTecEco Kiln Technology Remember:

The reactivity of most calcined materials including magnesia is a function of the state of disorder, specific surface area and 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.

– CO2 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 BasisEnergy – On a Mass Basis

Relative to Raw Material Used to make Cement

From Manufacturing Process Energy Release 100% Efficient (Mj.tonne-1)

From Manufacturing Process Energy Release with Inefficiencies (Mj.tonne-1)

Relative Product Used in Cement



Relative to Mineral Resulting in Cement



CaCO3 +

Clay 1545.73 2828.69

Portland Cement 1807 3306.81

Hydrated OPC 1264.90 2314.77

CaCO3 1786.09 2679.14 Ca(OH)2 2413.20 3619.80

MgCO3 1402.75 1753.44 MgO 2934.26 3667.82 Mg(OH)2 2028.47 2535.59

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Energy – On a Volume BasisEnergy – On a Volume Basis

Relative to Raw Material Used to make Cement

From Manufacturing Process Energy Release 100% Efficient (Mj.metre-3)

From Manufacturing Process Energy Release with Inefficiencies (Mj.metre-3)

Relative Product Used in Cement



Relative to Mineral Resulting in Cement



CaCO3

+ Clay 4188.93 7665.75Portland Cement 5692.05 10416.45

Hydrated OPC 3389.93 6203.58

CaCO3 6286.62 8429.93 Ca(OH)2 5381.44 8072.16

MgCO3 4278.39 5347.99 MgO 9389.63 11734.04 Mg(OH)2 4838.32 6085.41

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Abatement –TecEco Eco-CementsAbatement –TecEco Eco-Cements

Eco-cements in porous products absorb carbon dioxide from the atmosphere. Brucite carbonates forming hydromagnesite and magnesite, completing the thermodynamic cycle.

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.

Portland Cements 15 mass% Portland cement, 85 mass% aggregate

Emissions

.32 tonnes to the tonne. After carbonation. Approximately .299 tonne to the tonne.

Greater Sustainability

.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.

Capture CO2 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate.

Emissions

.25 tonnes to the tonne. After carbonation. approximately .140 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.

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 AbatementGlobal AbatementWithout CO2 Capture during manufacture (billion tonnes)

With CO2 Capture during manufacture (billion tonnes)

Total Portland Cement Produced Globally 1.80 1.80

Global mass of Concrete (assuming a proportion of 15 mass% cement)

12.00 12.00

Global CO2 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 CO2

Emissions

2.88 2.88

CO2 Emissions released by Eco-Cement 2.59 1.34

Resulting Abatement of CO2 emissions by

Substituting Eco-Cement

0.29 1.53

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Abatement from SubstitutionAbatement from Substitution

Figures are in millions of Tonnes

Building Material to be substituted

Realistic % Subst-itution by TecEco technology

Size of World Market (million tonnes

Substituted Mass (million tonnes)

CO2 Factors (1)

Emission From Material Before Substitution

Emission/Sequestration from Substituted Eco-Cement (Tonne for Tonne Substitution Assumed)

Net Abatement

Emissions - No Capture

Emissions - CO2 Capture

Abatement - No Capture

Abatement CO2 Capture

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 could substitution mean greater market share?

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TecEco Movie TheatreTecEco Movie Theatre

Discovery Channel Movie on Eco-Cements

Shown courtesy Discovery Channel Canada

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??????

Autogenous healing Coatings –a good or a bad thing?

all i ask is that the industry think about what i am saying. john harrison b.sc. b.ec. fcpa

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