Presentation downloadable from 1 TecEco Technology and Geopolymers I will have to race over some...

1Presentation downloadable from www.tececo.com

TecEco Technology and Geopolymers TecEco Technology and Geopolymers

I 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.

It is time to deploy new technology materials like geopolymers and TecEco cement binders that offer

waste utilisation, emissions reduction, capture and

sequestration.

It is time to deploy new technology materials like geopolymers and TecEco cement binders that offer

waste utilisation, emissions reduction, capture and

sequestration.

Auguste Rodin “The Thinker”

Sustainability will be the biggest business on the planet if we want to survive the future.

Can we create more polymeric non

hydration species using Ca-Mg

cements?


TecEco Binder Systems and GeopolymerTecEco Binder Systems and Geopolymer

Geopolymers and TecEco binders have much in common. Both are sustainable materials with common deployment

issues e.g.– Response to the reality of carbon taxes.– Lobby groups and competition product associations e.g.

• Portland cement industry putting out information to diffuse and confuse regarding geopolymer and TecEco technology.

– Lobby groups having a disproportionate say on government committees etc.

– Research development and deployment issues. – Energy issues.– Government policy issues.– Development of standards and codes of practice?

Can we learn from each other? Can we help each other? There are also features of tec-cement chemistry that invoke

hydrolysis and more polymeric reactions.There are definitely benefits to co-operation between the two emerging technologies e.g. EU research funding.


The Problem – A Planet in CrisisThe Problem – A Planet in Crisis

TecEco are in the BIGGEST

Business on the Planet - Solving Sustainability

Problems Economically

TecEco are in the BIGGEST

Business on the Planet - Solving Sustainability

Problems Economically

A Planet in Crisis?


A Demographic Explosion A Demographic Explosion

?

Developed Countries

Undeveloped Countries

Global population, consumption per capita and our footprint on the planet is exploding.


Atmospheric Carbon DioxideAtmospheric Carbon Dioxide


Global Temperature AnomalyGlobal Temperature Anomaly


The Techno-ProcessThe Techno-ProcessOur 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

Earth Systems

Atmospheric composition, climate, land cover, marine ecosystems, pollution, coastal zones, freshwater systems, salinity and global biological diversity have all been substantially affected.

Move 500-600 billion

tonnes

Use some 50 billion

tonnes


Ecological FootprintEcological Footprint

Our footprint is exceeding the capacity of the planet to support it. We are not longer sustainable as a species and must change our ways


Impact of the Largest Material Flow - Cement and ConcreteImpact 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 2.1 tonnes per person per annum

TecEco Pty. Ltd. And the geopolymer industry both have important technologies for

improvement in sustainability and properties

TecEco Pty. Ltd. And the geopolymer industry both have important technologies for

improvement in sustainability and properties


Embodied Energy of Building MaterialsEmbodied Energy of Building Materials

Downloaded from www.dbce.csiro.au/ind-serv/brochures/embodied/embodied.htm (last accessed 07 March 2000)

Concrete is relatively environmentally friendly and has a relatively low embodied energy


Average Embodied Energy in BuildingsAverage Embodied Energy in Buildings

Downloaded from www.dbce.csiro.au/ind-serv/brochures/embodied/embodied.htm (last accessed 07 March 2000)

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.

Most of the embodied energy in the built environment is in concrete.


Emissions from Cement ProductionEmissions from Cement Production Chemical Release

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

CaCO3 →CaO + ↑CO2

Process Energy– Most energy is derived from fossil fuels.

– Fuel oil, coal and natural gas are directly or indirectly burned to produce the energy required releasing CO2.

The production of cement for concretes accounts for around 10% of global anthropogenic CO2.

– Pearce, F., "The Concrete Jungle Overheats", New Scientist, 19 July, No 2097, 1997 (page 14).

The article by Fred Pearce was based on a 1994 article by Joseph Davidovits of the Geopolymer Institute titled “Global Warming Impacts on the Cement and Aggregates Industries.” World Resources Review, pages 263-278, volume 6, number 2.

CO2

CO2

CO2

CO2


Cement Production = Carbon Dioxide EmissionsCement Production = Carbon Dioxide Emissions

0

500,000,000

1,000,000,000

1,500,000,000

2,000,000,000

2,500,000,000

Metric Tonnes

1926

1931

1936

1941

1946

1951

1956

1961

1966

1971

1976

1981

1986

1991

1996

2001

Year

Between geopolymers, tec, eco and enviro-cements we can provide a viable much more sustainable alternative.


SustainabilitySustainabilitySustainability is a direction not a

destination.Our approach should be

holistically balanced and involve– Everybody, every process, every day.

Geopolymers + TecEco Cements= Low Emissions ProductionMineral Sequestration + Waste utilization

Geological Seques-tration

Emissions reductionthrough efficiency andconversion to non fossil fuels

+ +

Common Contributions?


Materials Affect Underlying Molecular FlowsMaterials Affect Underlying Molecular Flows

Take only renewables

→ Manipulate → Make → Use →Waste only what is biodegradable or can be re-assimilated

ReuseRe-make

Recycle

[ ←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 andwhat 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.

e.g. heavy metals, cfc’s, c=halogen compounds and CO2


Innovative New Materials - the Key to SustainabilityInnovative New Materials - the Key to Sustainability

Biosphere - Geosphere Techno - World

Materials are the substance of the techno-process, the link between the biosphere and techno-sphere and the key to sustainability. They are everything between and define the take and waste.

There is no such place as “away”, only a global commons

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.


Sustainability = Culture + TechnologySustainability = Culture + TechnologyIncrease in demand/price ratio for sustainability due to educationally induced cultural drift.

#

$

Demand

Supply

Increase in supply/price ratio for more sustainable products due to innovative paradigm shifts in technology.

Equilibrium shiftECONOMICS

Greater Value/for impact (Sustainability) and economic growth

Sustainability is where Culture and Technology meet.

Demand Supply

New Technical Paradigms are required that

deliver sustainability. (TecEco and

geopolymers.)


Huge Potential for Sustainable Materials in the Built Environment

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.

Construction materials comprise– 70% 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.– Reducing emissions and other impacts during manufacture.– Including carbon in materials so they become carbon sinks (eco-

cements).– including wastes for

their physical properties aswell as chemical compositionso they become resources.

C

CC

C

C

Waste

Waste


TecEco TechnologiesTecEco 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 Technology

– Combined 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 MgO

– Being 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.

TecEco

EconomicunderKyoto?

TecEco


TecEco Kiln TechnologyTecEco Kiln TechnologyTec-Kiln technology will be the first non fossil

fuel industrial process.– variable energy input.– Made from geopolymers.– Suitable for the manufacture of MgO, CaO and

metakaolin. Eventually Portland cement.Grinds and calcines at the same time.Runs 25% to 30% more efficiency.Theoretically capable of producing much

more reactive MgO as well as metakaolin and other input materials for geopolymers.


TecEco Kiln TechnologyTecEco Kiln Technology

CO2

Captures CO2 for bottling and sale.– To the oil industry (geological

sequestration).– Coca Cola?

Can be run cyclicly as part of a major process to solve global CO2 problems.

Will result in new markets for ultra reactive low lattice energy MgO (e.g. paper and environment industries).

TecEco plan to use geopolymer materials for the kiln capable of withstanding high temperatures.


Drivers for TecEco & Geopolymer TechnologyDrivers for TecEco & Geopolymer Technology

Producer PushThe opportunity cost of compliant waste disposalProfitability and cost recoveryTechnical meritResource issuesRoboticsResearch objectives

Consumer PullEnvironmental sentimentFear of climate changeCostTechnical advantagesCompetition

Government Influence

Carbon Taxes

Provision of Research Funds

Environmental education

Huge Existing Markets

Cement >2 billion tonnes.

New markets e.g. Bingham mixtures for robots, kilns, fireproof materials etc.

The way forward is through solving problems in niche markets and delivering sustainability.


TecEco Cement ConcretesTecEco Cement Concretes

More information at www.tececo.com


TecEco CementsTecEco CementsSUSTAINABILITY

DURABILITY STRENGTHTECECO CEMENTS

Hydration of the various components of a hydraulic cement such as Portland cement for strength. Note that geopolymers are esp. included

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.

HYDRAULIC CEMENT

+ or - POZZOLAN

MAGNESIA


The Magnesium Thermodynamic CycleThe Magnesium Thermodynamic Cycle

An alkaline environment in which silicates form

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

Carbonation Mg(OH)2 + CO2 + 2H2O MgCO3.3 H2O ΔH = -175.59 kJ.mol-1 ΔG = -38.73 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 Nesquehonite

? Representative of other hydrated mineral carbonates including an amorphous phase and lansfordite Magnesite*

Magnesia

Dehydration

CO2

Brucite*

Tec - Cements

Eco - Cements


TecEco FormulationsTecEco Formulations Tec-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.


TecEco Cement TechnologyTecEco 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 and

TecEco add reactive magnesia– which hydrates, consuming water and concentrating alkalis

forming brucite which is another alkali, but much less soluble, mobile or reactive than Portlandite.

In Eco-cements brucite carbonates

The consequences of need to be considered.


Strength with Blend & PorosityStrength with Blend & Porosity

STRENGTH ON ARBITARY SCALE 1-100

0

50

100

150

100-15050-1000-50

High PC

Tec-cement concretes

Eco-cement concretes

Enviro-cement concretes

High Porosity

High Magnesia

Tec – cement concretes have more polymeric species because they are much more alkaline during the early plastic phase.


Why Add Reactive Magnesia?Why 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 raise the early Ph.– Increasing non hydraulic strength giving reactions

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 durable Because 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


In the presence of water magnesium does not appear to be an important network former in silicate structures including geopolymers at room temperature and this is probably because of it’s high affinity for water which it seems to retain even when it carbonates.There are however other intriguing ramifications of adding reactive MgO.

Tec-Cements & GeopolymersTec-Cements & Geopolymers

More information at www.tececo.com


The Form of MgO - Overcoming DogmaThe Form of MgO - Overcoming Dogma

In 1917 the US National Bureau of Standards (now the National Bureau of standards and Technology) and the American Society for Testing Materials established a standard formula for Portland cement which excluded MgO in any form.

We now know that it is lattice energy that causes the difference between amorphous magnesia and periclase

TecEco have proved that amorphous magnesia, having no lattice energy to overcome, is safe to use in water based binder systems.


The Form of MgO - Lattice Energy Destroys a MythThe Form of MgO - Lattice Energy Destroys a Myth

Magnesia, 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, and– will completely hydrate in the same time order as the minerals

contained in most hydraulic cements. Dead burned magnesia and lime have high lattice

energies– Crystalline magnesium oxide or periclase has a calculated lattice

energy of 3795 Kj mol-1 which must be overcome for it to go into solution or for reaction to occur.

– Dead burned magnesia is much less expansive than dead burned lime in a hydraulic binder (Ramachandran V. S., Concrete Science, Heydon & Son Ltd. 1981, p 358-360 )


Tec-Cement Concrete Strength Gain CurveTec-Cement Concrete Strength Gain Curve

strength gain with less cement and added pozzolans is of great economic and environmental importance.

Tec – Cement Concrete with 10% reactive magnesia

OPC Concrete

HYPOTHETICAL TEC-CEMENT STRENGTH GAIN CURVE MPa

Log Days Plastic Stage

? ?

?

?

7 14 28 3

The use of tec-cement results in– 20-30% 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 time

We have observed this sort of curve in over 300 cubic meters of concrete now


Tec-Cement ReactionsTec-Cement ReactionsMgO + H2O => Mg(OH)2.nH2O - water consumption resulting in greater density and higher alkalinity.

Higher alkalinity => more reactions involving silica & alumina.

Mg(OH)2.nH2O => Mg(OH)2 + H2O – slow release water for more complete hydration of PC

MgO + Al + H2O => 3MgO.Al.6H2O ??? – equivalent to flash set??

MgO + SO4-- => various Mg oxy sulfates ?? –

yes but more likely ettringite reaction consumes SO4

-- first.

MgO + SiO2 => MSH ?? Yes but high alkalinity required. Strength??

We think the reactions are relatively independent of PC reactions


Non hydration Reactions in Tec-Cement Concretes?Non hydration Reactions in Tec-Cement Concretes?

MgO + H2O => Mg(OH)2.nH2O - water consumption– Increases density.– Raises the alkalinity during the early plastic stage.

Better pozzolanic reactions, surface hydrolysis and re-bonding as well as the formation of more polymeric not necessarily hydraulic species.– Resulting mineralization more similar to Roman cement

concretes that contained more Mg and more polymeric species.


13.7

pH

Log Time

10.5

Tec – Cement Concrete with 10% reactive magnesia (red). Ph maintained by brucite

OPC Concrete

HYPOTHETICAL pH CURVES OVER TIME (with fly ash)

Plastic Stage

? ?

?

Tec-Cement (red) - more affective pozzolanic reactions

11.2

OPC Concrete – Lower long term pH due to consumption of lime and carbonation

Surface hydrolysis and more polymeric species?

Tec-Cement pH CurvesTec-Cement pH Curves


ConjectureConjecture Why does Mg keep turning up in discussion

of ancient mineral systems (Egyptians, Mesopotamians and Romans)??

Maybe sepiolite (polygorskite with Al?) are carrier minerals that break down as the alkalinity rises delivering soluble and mobile SiO2 and Al2O3 for reactions forming more polymeric minerals.This idea emerged over too many drinks with Herbert Baier of PCI (part of Degussa) on the 29th June in Saint Quentin, France. It’s conjecture, interesting and not completely daft.


Role of Mg++ in Geopolymerism??!Role of Mg++ in Geopolymerism??!

Mg4Si6O15(OH)2.6H2O (sepiolite)+ clay + sodium or potassium salt => Geopolymer (Si-O-Al-O-Si ??) + brucite + more sepiolite??

or

Sepiolite + clay + H2O + CO2 + OH-

Geopolymer + sepiolite + salt??

Sepiolite precipitates from salty alkaline waters in arid environments and was available to the Egyptians. Does explain role of Mg in Egyptian cements.


Strength Development in Tec-Cements.Strength Development in Tec-Cements.

Reactive magnesia requires considerable water to hydrate resulting in:– A significantly lower voids/paste ratio i.e. denser,

less permeable concrete.

– 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?

Could the role of added reactive magnesia be to consume water like the ettringite reaction in PC concretes. This property could be useful with geopolymers to overcome the viscosity problem.


Water Reduction During the Plastic Phase?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 increased density and concentration of

alkalis - less shrinkage and cracking and improved strength and durability.

Water

Log time

Observable Characteristic

Relevant Fundamental

Voids

Binder + supplementary cementitious materials

Hydrated Binder Materials

High water for ease of placement

Less water for strength and durability

Variables such as % hydration of mineral, density, compaction, % mineral H20 etc.

Consumption of water during plastic stage

Unhydrated Binder

Ph

Water Reduction.


For more effective reactions in hydraulic concretes like PC and in “geopolymer concretes” high alkalinity is required.– To achieve high alkalinity it is necessary to not add too much water –

this results in higher viscosity.

– To place concretes low viscosity is required.

Tec-cement concretes achieve high alkalinity by internal water removal.– The dichotomy between viscosity and ease of placement defines much

of the current research on geopolymers and for that matter in relation to additives for PC.

Depending on the level of alkalinity reached, many of the particles of fly ash or dehydrated clay (Kandoxi) polymerise, react at the surface only (hydrolyse and re-bond) or remain as micro-aggregates.

High Alkalinity Common to Both Hydraulic and Geopolymer Systems => Better Reactions.

High Alkalinity Common to Both Hydraulic and Geopolymer Systems => Better Reactions.


Adding Reactive MgOAdding Reactive MgO Portland cements stoichiometrically require around 23 -25% water

for hydration yet we add approximately 45 to 50% at cement batching plants to fluidise the mix sufficiently for placement.

If it were not for the enormous consumption of water by tri calcium aluminate as it hydrates forming ettringite in the presence of gypsum, concrete would remain as a weak mush and probably never set.

– 26 moles of water are consumed per mole of tri calcium aluminate to from a mole of solid ettringite. When the ettringite later reacts with remaining tri calcium aluminate to form monosulfoaluminate hydrate a further 4 moles of water are consumed.

The addition of reactive MgO achieves water removal in a similar way.– Can reactive MgO be used to get over the viscosity issue in geopolymers?– Would this be cheaper than using super plasticisers?


Adding Reactive MgO to GeopolymersAdding Reactive MgO to Geopolymers It is not possible to add water to geopolymers. If water were add the

alkalis would be diluted, the pH would fall and the mix would not set as unlike the setting of Portland cement concretes there is no reaction that consumes water. On the contrary – water is expelled.

Reactive magnesia is a water removal tool and may be useful as an adjunct to assist with the viscosity problem.

Most people researching geopolymers seem to be trying various super, duper, hyper, blah blah plasticiser molecules to see if they can be used to fluidise the mix sufficiently.

The water removal mechanism of magnesia and its plasticising properties may be useful as a totally different approach to get over the viscosity issue. There is obviously more work to do pending funding but could it be that the best features of geopolymeric and hydraulic cements can be combined?– There are more polymeric species in Roman cements.


Non Newtonian RheologyNon Newtonian Rheology

O

O

O

O Mg++

+

- +

+

+

+

+

+

+

+

+

O +

+

+

+

+

+

O

O O

- -

- -

-

-

The 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 pozzolan

It is not known how deep these layers get

Etc.

Etc.

Ca++ = 114, Mg++ = 86 picometres


MgO Changes Surface Charge as the Ph RisesMgO Changes Surface Charge as the Ph Rises

+

+

+

+

++

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+Mutual Repulsion=

>

+

+

+

+

++

+

+

+

+

+

+

+

+

-

-

-

-

-

-

-Mutual Attraction

This could be the reason for the greater tensile strength displayed during the early plastic phase of tec-cement concretes.

Ph 12 ?

Cement

Cement

MgO Sand

SandMgO


Tec-Cement Tensile StrengthTec-Cement Tensile Strength

TEC - CEMENT TENSILE STRENGTH

0

1

2

3

4

5

6

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

CURING TIME (days)

ST

RE

NG

TH

(M

Pa)

OPC(100%)

OPC(90%)+ MgO(10%)

Graphs by Oxford Uni Student

Tensile 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


RheologyRheology

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.

Second layer low slump tec-cement concrete Tech Tendons

First layer low slump tec-cement concrete

A range of pumpable composites with Bingham plastic properties will be required in the future as buildings will be “printed.” (Robotics)


Technical Comparisons Geopolymers and Tec-Cement Concretes

Technical Comparisons Geopolymers and Tec-Cement Concretes

Tec-Cement Concretes Geopolymers

Can use a high proportion of pozzolanic materials

Use a high proportion of pozzolanic materials

Low temperature heat curing only.

Often but not always require heat curing

Low shrinkage Low shrinkage

More durable than PC concretes but not as acid resistant than Geopolymers

Durable acid and alkali resistant.


Technical Comparisons Geopolymers and Tec-Cement Concretes (2)

Technical Comparisons Geopolymers and Tec-Cement Concretes (2)

Tec-Cement Concretes Geopolymers

Fire retardants (Water or CO2

releases. MgO is a smoke absorbent.

Heat resistant

Higher tensile strength than PC concretes

Higher tensile strength than PC concretes

Lower heat of hydration than pure PC concretes.

Very low heat of hydration

Not attacked by sulfate and chloride.

Not attacked by sulfate and chloride.


Other Comparisons = Common ProblemsOther Comparisons = Common Problems

Tec-Cement Concretes GeopolymersAre a system. i.e. no single formulation ideal

Are a system. i.e. no single formulation ideal

More sustainable with reduced net emissions. (Eco-cements can be net carbon sinks)

More sustainable with reduced net emissions.

Disruption by the PC industry- Diffuse and confuse the science.- Lack of understanding => “put downs”

Disruption mentioned by Grant Lukey, Robert Temple, Davidovits and others.

Not fragmented (yet). Fragmented – too many patents

Standards ban MgO regardless of form.

Standards suit PC not geopolymers.


TecEco and Geopolymer GroupsTecEco and Geopolymer Groups

Mutual response to government– Changing standards to performance based.– Policy issues

• Procurement policies designed to foster new more sustainable materials technologies.

• Funding for sustainable new materials.

Mutual promotion of sustainability. Educational – the buying public Counter subversive tactics by the PC lobby

There are definitely benefits to co-operation between the two emerging technologies e.g. EU research funding.


TecEco and the PC Cement IndustryTecEco and the PC Cement Industry

The PC industry should:– Spend a little more money on research to move

cementitous composites into better market space.– Spend a little less on litigation, remediation and

arbitration because of the imperfect material they have.

Worth thinking about in context of carbon taxes?


TecEco Cement Implementation

Summary

TecEco Cement Implementation

Summary


High Performance-Lower Construction CostsHigh 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 required Increased 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?


TecEco Concretes - Lower Construction Costs (2)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.


SummarySummary 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 Change Pollution

Durability Corrosion

Strength Delayed Reactions

Placement , Finishing Rheology

Shrinkage Carbon Taxes


TecEco Doing Things

TecEco Doing Things


The Use of Eco-Cements for Building Earthship BrightonThe 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.

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.


Repair of Concrete Blocks. Clifton Surf ClubRepair 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.


Mike Burdon’s Murdunna WorksMike 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:

1. 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.

2. 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.

3. Strength gain was more rapid than with Portland cement controls from the same premix plant and continued for longer.

4. 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 formulation


Tec-Cement Slab Whittlesea, Vic. AustraliaTec-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 - 133 micro strains, 14 days - 240 micro strains, 28 days - 316 micros strains and at 56 days - 470 microstrains.

Strength Development of Tec-Cement Concrete

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