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A Planet in Crisis

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Title: A Planet in Crisis


1
A Planet in Crisis
TecEco are in the BIGGEST Business on the Planet
Economic Solutions to Global Warming and Waste
The Problem - A Planet in Crisis
2
A Demographic Explosion
Undeveloped Countries
Developed Countries
Global population, consumption per capita and our
footprint on the planet is exploding.
3
Ecological Footprint Exceeds Capacity
Source WWF State of the Planet
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
4
One Planet, Many People, Many Problems
5
Global Temperature Anomaly
6
Atmospheric Carbon Dioxide
7
The Carbon Cycle and Emissions
Emissions from fossil fuels and cement production
are the cause of the global warming problem
Units GtC GtC/yr
Source David Schimel and Lisa Dilling, National
Centre for Atmospheric Research 2003
8
Techno-Processes Earth Systems
Underlying the techno-process that describes and
controls the flow of matter and energy are
molecular stocks and flows. If out of tune with
nature these moleconomic flows have detrimental
affects on earth systems.
Bio-sphere
Geo-sphere
Earth Systems Atmospheric composition, climate,
land cover, marine ecosystems, pollution, coastal
zones, freshwater and salinity.
Detrimental affects on earth systems
Waste
Take
Move 500-600 billion tonnesUse some 50 billion
tonnes
Manipulate, Make and Use
Techno-sphere
To reduce the impact on earth systems new
technical paradigms need to be invented that
result in underlying molecular flows that mimic
or at least do not interfere with natural flows.
9
Techno-Processes Affect Underlying Molecular Flows
Take ? Manipulate ? Make ? Use ? Waste
?Materials?
? Underlying
molecular flow ?
If the underlying molecular flows are out
of tune with nature there is damage to the
environmente.g. heavy metals, cfcs, chalogen
compounds and CO2
MoleconomicsIs the study of the form of atoms in
molecules, their flow, interactions, balances,
stocks and positions. What we take from the
environment around us, how we manipulate and make
materials out of what we take and what we waste
result in underlying molecular flows that affect
earth systems. These flows should mimic or
minimally interfere with natural flows.
10
Moleconomics The Economics of Molecules
  • Moleconomics is the study of the form of atoms in
    molecules, their flow, interactions, balances,
    stocks and position on scales ranging from local
    to universal.
  • The word moleconomics is a new word for a new
    and still evolving discipline involving the study
    of the form of atoms in molecules, their flow,
    interactions, balances, stocks and positions on
    scales ranging from local to universal (1)
  • Unnatural moleconomic imbalances have resulted in
    stocks of some molecules such as carbon dioxide,
    CFCs, and heavy metals in undesirable positions
    such as the global commons.
  • Anthropoid technical paradigms, driven by fossil
    fuels and used by techno-processes in the
    techno-sphere result in an underlying flows of
    molecules. Flows are to positions and result in
    stocks, some of which are unnaturally high or
    low. The study of this process is the science of
    moleconomics
  • By changing the technical paradigms we can
    redefine the moleconomics of the planet.
  • John Harrison invented the word because there
    were difficulties with words like molecular
    ecology and molecular economics which were used
    with a different meaning to that considered
    logical given their roots.

11
Changing Techno-process
Take gt manipulate gt make gt use gt wasteDriven
by fossil fuel energy with detrimental effects on
earth systems.
ReduceRe-useRecycle
Eco-innovate
If you cant recycle based on chemical property
Do so based on physical properties such as weight
and strength
Materials
12
Changing Technical Paradigms
  • By enabling us to make productive use of
    particular raw materials, technology determines
    what constitutes a physical resource1
  • Pilzer, Paul Zane, Unlimited Wealth, The Theory
    and Practice of Economic Alchemy, Crown
    Publishers Inc. New York.1990

By inventing new technical paradigms and
re-engineering materials that are economic to
produce we can change the underlying molecular
flows that are damaging this planet.
Imagination is more important than knowledge.
Knowledge is limited. Imagination encircles the
world. Albert Einstein
We must make materials that have underlying
molecular flows that mimic or at least do not
disrupt natural flows, that require less energy
to make, last much longer and contribute
properties that reduce lifetime energies.
13
Drivers for Change
The challenge is to harness human behaviours
which underlay economic supply and demand
phenomena by changing technical paradigm in
favour of greater sustainability.
14
Economically Driven Change
New, more profitable technical paradigms used in
the techno-process that result in more
sustainable and usually more efficient
moleconomic flows that mimic or at least do not
disrupt natural flows are required.
- ECONOMICS -
15
Examples of Economic Changes in Technical
Paradigms that result in Greater Sustainability
Light Globes - A Recent Paradigm Shift in
Technology Reducing Energy Consumption Light
Globes in the last 10 years have evolved from
consuming around 100 watts per 1700 lumens to
less that 20 watts per 1700 lumens. As light
globes account for around 30 of household energy
this is as considerable saving.
Robotics - A Paradigm Shift in Technology that
will fundamentally affect Building and
Construction Construction in the future will be
largely done by robots because it will be more
economic to do so. Like a color printer different
materials will be required for different parts of
structures, and wastes such as plastics will
provide many of the properties required for the
cementitious composites of the future used. A
non-reactive binder such as TecEco tec-cements
can supply the right rheology, and like a
printer, very little will be wasted.
16
Sustainability Driven by Economics
  • Our goal should be
  • To develop technical paradigms that more
    economically deliver reduced moleconomic impacts
    and thus greater sustainability.
  • To do this we need to
  • Through education to induce cultural change to
    increase the demand for sustainability.
  • Innovate to change the technical paradigms
  • Improvements in technical paradigms will bring
    about changes in demand affecting resource usage
    and thus underlying moleconomic flows reducing
    detrimental linkages with the planet.
  • TecEco Tec, Eco and Enviro cements are innovative
    sustainability enabling technologies.

17
Sustainability Culture Technology
Increase in demand/price ratio for sustainability
due to educationally induced cultural drift.

Supply
Greater Value/for impact (Sustainability) and
economic growth
Equilibrium shift
ECONOMICS
New Technical Paradigms are required that deliver
sustainability.
Demand
Increase in supply/price ratio for more
sustainable products due to innovative paradigm
shifts in technology.

Sustainability could be considered as where
culture and technology meet.
18
The TecEco CarbonSafe Geo-Photosynthethic Process
The CarbonSafe Geo-Photosynthetic Process is
TecEcos evolving techno-process that delivers
profitable outcomes whilst reversing underlying
undesirable moleconomic flows from other less
sustainable processes.
Inputs Atmospheric or smokestack CO2,
brines,waste acid, other wastes Outputs Potable
water, gypsum, sodium bicarbonate, salts,
building materials, bottled concentrated CO2 for
geo-sequestration and other uses.
Solar or solar derived energy
TecEcoKiln
TecEco MgCO2 Cycle
MgO
MgCO3
Greensols Process
MgO
1.29 gm/l Mg
Coal
Fossil fuels
Carbon or carbon compoundsMagnesium oxide
CO2
Oil
19
TecEco CarbonSafe Geo-Photosynthetic Process
Vectors
20
The CarbonSafe Geo-Photosynthetic Process
1.354 x 109 km3 Seawater containing 1.728 1017
tonne Mg or suitable brines from other sources
Seawater Carbonation Process
Waste Acid
Gypsum carbon waste (e.g. sewerage)
fertilizers
Bicarbonate of Soda (NaHCO3)
CO2 from power generation or industry
Other salts Na,K, Ca2,Cl-
Gypsum (CaSO4)
Sewerage compost
CO2 as a biological or industrial input or if no
other use geological sequestration
Magnesite (MgCO3)
Solar Process to Produce Magnesium Metal
Magnesium Thermodynamic Cycle
Simplified TecEco ReactionsTec-Kiln MgCO3 ? MgO
CO2 - 118 kJ/moleReactor Process MgO CO2 ?
MgCO3 118 kJ/mole (usually more complex
hydrates)
CO2 from power generation, industry or out of the
air
Magnesite (MgCO3)
Magnesia (MgO)
Hydroxide ReactorProcess
Sequestration Table Mg from Seawater
Eco-CementTec-Cement
Other Wastes
21
The MgCO2 Process (Magnesium Thermodynamic Cycle)
The magnesium thermodynamiccycle is very
important for sequestration and is used for the
formation of valuable building product
MgCO3? MgO CO2 ?H 118.28 kJ.mol-1 ?G 65.92
kJ.mol-1
Calcination
CO2 CaptureNon fossil fuel energy
Magnesite
Calcination
Dehydration
Eco-Cements
TOTAL CALCINING ENERGY (Relative to
MgCO3) Theoretical 1480 kJ.Kg-1 With
inefficiencies 1948 kJ.Kg-1
Representative of other hydrated mineral
carbonates including an amorphous phase and
lansfordite
Magnesia
Nesquehonite
Carbonation
Hydration MgO H2O ? Mg(OH)2.nH2O ?H -81.24
kJ.mol-1 ?G -35.74 kJ.mol-1
Carbonation Mg(OH)2.nH2O CO2 2H2O? MgCO3.3
H2O ?H -175.59 kJ.mol-1 ?G -38.73 kJ.mol-1
Brucite
Tec and Enviro-Cements
22
Why Magnesium Carbonates for Sequestration?
  • Because of the low molecular weight of magnesium,
    magnesium oxide which hydrates to magnesium
    hydroxide and then carbonates, is ideal for
    scrubbing CO2 out of the air and sequestering the
    gas into the built environment
  • More CO2 is captured than in calcium systems as
    the calculations below show.
  • An area 10km by 10m by 150m deep of magnesium
    carbonate will sequester all the excess CO2 we
    release to the atmosphere in a year.
  • At 2.09 of the crust magnesium is the 8th most
    abundant element
  • Magnesium minerals are potential low cost. New
    kiln technology from TecEco will enable easy low
    cost simple non fossil fuel calcination of
    magnesium carbonate with CO2 capture for
    geological sequestration.

23
Reduction Global CO2 from CarbonSafe Process
24
Carbonate Sequestration in Built Environment
25
TecEco Kiln Technology
  • Can run at low temperatures.
  • Can be powered by various non fossil fuels.
  • Runs 25 to 30 more efficiently.
  • Theoretically capable of producing much more
    reactive MgO
  • Even with ores of high Fe content.
  • Captures CO2 for bottling and sale to the oil
    industry (geological sequestration).
  • Grinds and calcines at the same time.
  • Part of a major process to solve global CO2
    problems.
  • Will result in new markets for ultra reactive low
    lattice energy MgO (e.g. cement, paper and
    environment industries)
  • TecEco need your backing to develop the kiln

26
A Post Carbon Waste Age?
New techno-process are required that mimic nature
and do not change global system flows
27
Mimicking Natural Processes - Biomimicry
Since we now dominate this planet we need to
evolve technical paradigms that result in
techno-processes that mimic nature.
  • The term biomimicry was popularised by the book
    of the same name written by Janine Benyus
  • Biomimicry is a method of solving problems that
    uses natural processes and systems as a source of
    knowledge and inspiration.
  • It involves nature as model, measure and mentor.

The theory behind biomimicry is that natural
processes and systems have evolved over several
billion years through a process of research and
development commonly referred to as evolution. A
reoccurring theme in natural systems is the
cyclical flow of matter in such a way that there
is no waste of matter or energy.
28
Utilizing Carbon and Wastes (Biomimicry)
  • During earth's geological history large tonnages
    of carbon were put away as limestone and other
    carbonates and as coal and petroleum by the
    activity of plants and animals.
  • Sequestering carbon in magnesium binders and
    aggregates in the built environment mimics nature
    in that carbon is used in the homes or skeletal
    structures of most plants and animals.

In eco-cement blocks and mortars the binder is
carbonate and the aggregates are preferably wastes
We all use carbon and wastes to make our homes!
Biomimicry
29
Re - Engineering Techno-Processes and Materials
  • To solve environmental problems we need to
    understand more about the underlying moleconomic
    flows involved in the techno process including
  • the way their precursors are derived and their
    degradation products re assimilated
  • how we can reduce the impact of these
  • what energies drive the evolution, devolution and
    flow or materials in the techno process and
  • how we can reduce these energies
  • how materials impact on lifetime energies
  • With the knowledge gained re-design materials to
    not only be more sustainable but more sustainable
    in use

Environmental problems are the result of an
inherently flawed techno-process involving
materials, materials flows and their underlying
moleconomic and energy systems.
30
Materials in the Built Environment
  • The built environment is made of materials and is
    our footprint on earth.
  • It comprises buildings and infrastructure.
  • Building materials comprise
  • 70 of materials flows (buildings, infrastructure
    etc.)
  • 40-50 of waste that goes to landfill (15 of
    new materials going to site are wasted.)
  • At 1.5 of world GDP Annual Australian production
    of building materials likely to be in the order
    300 million tonnes or over 15 tonnes per person.
  • Over 20 billion tonnes of building materials are
    used annually on a world wide basis.
  • Mostly using virgin natural resources
  • Combined in such a manner they cannot easily be
    separated.
  • Include many toxic elements.

31
Huge Potential for More Sustainable Materials in
Construction
  • Reducing the impact of the take and waste phases
    of the techno-process.
  • including carbon in materialsthey are
    potentially carbon sinks.
  • including wastes forphysical properties aswell
    as chemical compositionthey become resources.
  • re engineeringmaterials toreduce the
    lifetimeenergy of buildings

Many wastes can contribute to physical properties
reducing lifetime energies
32
The TecEco Dream A More Sustainable Built
Environment
CO2
OTHERWASTES
CO2 FOR GEOLOGICAL SEQUESTRATION
PERMANENT SEQUESTRATION WASTE UTILISATION (Man
made carbonate rock incorporating wastes as a
building material)
MINING
MgO
TECECO KILN
MAGNESITE OTHER INPUTS
TECECO CONCRETES
RECYCLED BUILDING MATERIALS
We need materials that require less energy to
make them, that last much longer and that
contribute properties that reduce lifetime
energies
There is a way to make our city streets as green
as the Amazon rainforest. Fred Pearce, New
Scientist Magazine
SUSTAINABLE CITIES
33
Impact of the Largest Material Flow - Cement and
Concrete
  • Concrete made with cement is the most widely used
    material on Earth accounting for some 30 of all
    materials flows on the planet and 70 of all
    materials flows in the built environment.
  • Global Portland cement production is currently in
    the order of 2 billion tonnes per annum.
  • Globally over 14 billion tonnes of concrete are
    poured per year.
  • Over 2 tonnes per person per annum
  • Much more concrete is used than any other
    building material.

TecEco Pty. Ltd. have benchmark technologies for
improvement in sustainability and properties
34
Embodied Energy of Building Materials
Concrete is relatively environmentally friendly
and has a relatively low embodied energy
Downloaded from www.dbce.csiro.au/ind-serv/brochur
es/embodied/embodied.htm (last accessed 07 March
2000)
35
Average Embodied Energy in Buildings
Most of the embodied energy in the built
environment is in concrete.
Because so much concrete is used there is a huge
opportunity for sustainability by reducing the
embodied energy, reducing the carbon debt (net
emissions) and improving properties that reduce
lifetime energies.
Downloaded from www.dbce.csiro.au/ind-serv/brochur
es/embodied/embodied.htm (last accessed 07 March
2000)
36
Emissions 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).

CO2 CO2
Arguments that we should reduce cement production
relative to other building materials are nonsense
because concrete is the most sustainable building
material there is. The challenge is to make it
more sustainable.
37
Cement Production Carbon Dioxide Emissions
Between tec, eco and enviro-cements TecEco can
provide a viable much more sustainable
alternative.
38
Portland Cement Global Warming
  • Concrete is the third largest contributor to CO2
    emissions after the energy and transportation
    sectors.
  • The cement industry is growing at around 5 a
    year globally. Mainly China, Thialand and India.
  • On current trends world production of Portland
    cement will reach 3.5 billion tonnes by 2020 - a
    three fold increase on 1990 levels.
  • To achieve Kyoto targets the industry will have
    to emit less than 1/3 of current emissions per
    tonne of concrete.
  • Carbon taxes and other legislative changes will
    provide legislative incentive to change.
  • There is already strong evidence of market
    incentive to change

39
Concrete Industry Objectives
  • PCA (USA)
  • Improved energy efficiency of fuels and raw
    materials
  • Formulation improvements that
  • Reduce the energy of production and minimize the
    use of natural resources.
  • Use of crushed limestone and industrial
    by-products such as fly ash and blast furnace
    slag.
  • WBCSD
  • Fuels and raw materials efficiencies
  • Emissions reduction during manufacture

40
TecEco Technologies Take Concrete into the Future
  • More rapid strength gain even with added
    pozzolans
  • More supplementary materials can be used reducing
    costs and take and waste impacts.
  • Higher strength/binder ratio
  • Less cement can be used reducing costs and take
    and waste impacts
  • More durable concretes
  • Reducing costs and take and waste impacts.
  • Use of wastes
  • Utilizing carbon dioxide
  • Magnesia component can be made using non fossil
    fuel energy and CO2 captured during production.

Tec -Cements
Tec Eco-Cements
Eco-Cements
41
Greening Concrete
  • Scale down Production.
  • Untenable nonsense, especially to developing
    nations
  • Use waste for fuels
  • Not my area of expertise but questioned by many.
  • Reduce net emissions from manufacture
  • Increase manufacturing efficiency
  • Increase fuel efficiency
  • Waste stream sequestration using MgO and CaO
  • E.g. Carbonating the Portlandite in waste
    concrete
  • Given the current price of carbon in Europe this
    could be viable
  • TecEco have a mineral sequestration process that
    is non fossil fuel driven using MgO and the
    TecEco kiln

This is not going to happen
Not discussed
42
Greening Concrete
  • Increase the proportion of waste materials that
    are pozzolanic
  • Using waste pozzolanic materials such as fly ash
    and slags has the advantage of not only extending
    cement reducing the embodied energy and net
    emissions but also of utilizing waste.
  • We could run out of fly ash as coal is phasing
    out. (e.g. Canada)
  • TecEco technology will allow the use of marginal
    pozzolans
  • Slow rate of strength development can be
    increased using TecEco tec-cement technology.
  • Potential long term (50 year plus) durability
    issues overcome using tec-cement technology.
  • Replace Portland cement with viable alternatives
  • There are a number of products with similar
    properties to Portland cement
  • Carbonating Binders
  • Non-carbonating binders
  • The research and development of these binders
    needs to be accelerated

43
Greening Concrete
  • Use aggregates that extend cement
  • E.g. use air as an aggregate making cement go
    further
  • Aluminium use questionable
  • Foamed Concretes work well with TecEco eco-cement
  • Use for slabs to improve insulation
  • Use aggregates with lower embodied energy and
    that result in less emissions or are themselves
    carbon sinks
  • Other materials that be used to make concrete
    have lower embodied energies.
  • Local aggregates with lower transport embodied
    energies
  • Recycled aggregates from building rubble
  • Glass cullet
  • Materials that non fossil carbon are carbon sinks
    in concrete
  • Plastics, wood etc.
  • Improve the performance of concrete by including
    aggregates that improve or introduce new
    properties reducing lifetime energies
  • Wood fibre reduces weight and conductance.

44
Increasing the Proportion of Waste Materials that
are Pozzolanic
  • Advantages
  • Lower costs
  • More durable greener concrete
  • Disadvantages
  • Rate of strength development retarded
  • Potential long term durability issue due to
    leaching of Ca from CSH.
  • Glasser and others have observed leaching of Ca
    from CSH and this will eventually cause long term
    unpredictable behavior of CSH.
  • Resolved by presence of brucite in tec-cements
  • Higher water demand due to fineness.
  • Finishing is not as easy
  • Supported by WBCSD and virtually all industry
    associations
  • Driven by legislation and sentiment

45
More Pozzolan can be Used with Tec-Cement
Technology
  • The practical limit to adding pozzolan to
    conventional concretes is the rate of strength
    development.
  • TecEco tec-cements have an increased rate of
    strength development particularly in the first
    3-4 days.
  • Internal consumption of water by MgO as it
    hydrates reducing impact of fineness demand.
  • More pozzolanic and hydrolysis reactions.
  • Mg Al hydrates or Mg ettringite?
  • Improved durability as brucite is much less
    soluble or reactive
  • Potential long term durability issue due to
    leaching of Ca from CSH resolved.
  • Improved finishing as Mg contributes a strong
    shear thinning property overcoming the tendency
    to stickyness

In TecEco tec-cements Portlandite is consumed by
the pozzolanic reaction and replaced with brucite
46
Tec-Cement Concrete Strength Gain Curve
We have observed this kind of curve with over 300
cubic meters of concrete
The possibility of high early strength gain with
added pozzolans is of great economic and
environmental importance.
47
Volumetric Consequences of Replacement of PC by
Carbonating Binders
  • Lime
  • The most used material next to Portland cement in
    binders.
  • Generally used on a 13 paste basis since Roman
    times
  • Non-hydraulic limes set by carbonation and are
    therefore close to carbon neutral once set.
  • Ca(OH)2 CO2 gt CaCO3
  • 33.22 gas ? 36.93 molar volumes
  • Very slight expansion, but shrinkage from loss of
    water.

48
Volumetric Consequences of Replacement of PC by
Carbonating Binders
  • Eco-Cement (TecEco)
  • Have high proportions of reactive magnesium oxide
    which first hydrates and then carbonates like
    lime.
  • Generally used in a 18 pasteaggregate basis
    because much more carbonate binder is produced
    than with lime.
  • Consider the reactions
  • MgO H2O ltgt Mg(OH)2.1H2O
  • 11.20 18 ltgt 24.29 - 45
  • As yet uncharacterised expansion
  • Mg(OH)2 CO2 H2O ltgt MgCO3.3H2O
  • 58.31 44.01 ltgt 138.32 molar mass (at least!)
  • 24.29 gas 18 ltgt 74.77 molar volumes (at
    least!)
  • 307 expansion (less water volume reduction)
    producing much more binder per mole of MgO than
    lime (around 8 times)

Mostly CO2 and water
49
Eco-Cements
  • Eco-cement is based on blending reactive
    magnesium oxide with other hydraulic cements and
    then allowing the Brucite and Portlandite
    components to carbonate in porous materials such
    as concretes blocks and mortars.
  • The use of eco-cements for block manufacture,
    particularly in conjunction with the kiln also
    invented by TecEco (The Tec-Kiln) would result in
    sequestration on a massive scale.
  • As Fred Pearce reported in New Scientist Magazine
    (Pearce, F., 2002), There is a way to make our
    city streets as green as the Amazon rainforest.

Ancient and modern carbonating lime mortars are
based on this principle
50
CO2 Abatement in Eco-Cements
No Capture11.25 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 Cements15 mass Portland cement, 85
mass aggregate Emissions.32 tonnes to the
tonne. After carbonation. Approximately .299
tonne to the tonne.
Capture CO211.25 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 Ash11.25 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.
For 85 wt Aggregates 15 wt Cement
Eco-cements in porous products absorb carbon
dioxide from the atmosphere. Brucite carbonates
forming lansfordite, nesquehonite and an
amorphous phase, completing the thermodynamic
cycle.
Greater Sustainability
.299 gt .241 gt.140 gt.113Bricks, 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.
51
Replacement with Non Carbonating Binders
  • There are a number of other novel cements with
    intrinsically lower energy requirements and CO2
    emissions than conventional Portland cements that
    have been developed
  • High belite cements
  • Being research by Aberdeen and other universities
  • Calcium sulfoaluminate cements
  • Used by the Chinese for some time
  • Magnesium phosphate cements
  • Proponents argue that a lot stronger than
    Portland cement therefore much less is required.
  • Main disadvantage is that phosphate is a limited
    resource
  • Geopolymers

52
Geopolymers
  • Geopolymers consists of SiO4 and AlO4
    tetrahedra linked alternately by sharing all the
    oxygens.
  • Positive ions (Na, K, Li, Ca, Ba, NH4,
    H3O) must be present in the framework cavities
    to balance the negative charge of Al3 in IV fold
    coordination.
  • Theoretically very sustainable
  • Unlikely to be used for pre-mix concrete or waste
    in the near future because of.
  • process problems
  • Requiring a degree of skill for implementation
  • nano porosity
  • Causing problems with aggregates in aggressive
    environments
  • no pH control strategy for heavy metals in waste
    streams

53
TecEco Cements
TecEco concretes are a system of blending
reactive magnesia, Portland cement and usually a
pozzolan with other materials and are a key
factor for sustainability.
54
TecEco Cement Technology Theory
  • Portlandite (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

55
TecEco 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 voidspaste
    ratio, increasing density and possibly raising
    the short term pH.
  • Reactions with pozzolans are more effective.
    After all the Portlandite has been consumed
    Brucite controls the long term pH which is lower.
    Due to the low solubility, mobility and
    reactivity of Brucite, greater durability
    results.
  • 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.

56
TecEco Cements Impact on Sustainability
  • The CO2 released by calcined carbonates used to
    make binders can be captured using TecEco kiln
    technology.
  • Tec-Cements Develop Significant Early Strength
    even with Added Supplementary Materials.
  • Around 15 - 30 less total binder is required for
    the same strength.
  • Eco-Cements carbonate sequestering CO2 requiring
    25-75 less binder in some mixes
  • Both Tec and Eco-Cements provide a benign low pH
    environment for hosting large quantities of waste
    overcoming problems of
  • Using acids to etch plastics so they bond with
    concretes.
  • sulphates from plasterboard etc. ending up in
    recycled construction materials.
  • heavy metals and other contaminants.
  • delayed reactivity e.g. ASR with glass cullet
  • Resolving durability issues

57
Benefits to the Concrete Industry of Adopting
TecEco Technology
  • Utilizing wastes to make concretes.
  • Tec-Cements have more rapid strength development
    with fly ash, bottom ash, industrial slags etc.
    (Tec-Cements.)
  • Reducing energy and emissions during the
    production of cements.
  • MgO can be made using non fossil fuel energy
  • Concretes containing MgO
  • are demonstrably more durable.
  • can incorporate wastes that contribute to
    physical properties reducing lifetime energies
  • It makes sense to sequester carbon by allowing
    MgO to re-carbonate and thereby gain strength.

The biggest business on the planet is going to be
the sustainability business
58
Using Aggregates that Extend Cement
  • Air used in foamed concrete is a cheap low
    embodied energy aggregate and has the advantage
    of reducing the conductance of concrete.
  • Concrete, depending on aggregates weighs in the
    order of 2350 Kg/m3
  • Concretes of over 10 mp as light as 1000 Kg/m3
    can be achieved.
  • At 1500 Kg/m3 25 mpa easily achieved.
  • From our experiments so far with Buildlite
    Cellular Concrete PL tec-cement formulations
    increase strength performance by around 5-10 for
    the same mass.
  • Claimed use of aluminium and autoclaving to make
    more sustainable blocks questionable

59
Use Aggregates with Lower Embodied Energy and
that Result in less Emissions or that are
Themselves Carbon Sinks
  • Use of aggregates that lower embodied energies
  • wastes such as recycled building rubble. Tec and
    Eco-Cements do not have problems associated with
    high gypsum content.
  • Use of other aggregates that include non fossil
    carbon
  • sawdust and other carbon based aggregates can
    make Eco-Cement concretes a net carbon sink.
  • Reduce transport embodied energies by using local
    materials such as earth
  • mud bricks and adobe.
  • our research in the UK and with mud bricks in
    Australia indicate that eco-cement formulations
    seem to work much better than PC for this

60
Using Aggregates that are Wastes
  • TecEco cementitious composites represent a cost
    effective option for
  • using non traditional aggregates from on site
    reducing transports costs and emissions
  • use and immobilisation of waste.
  • Because they have
  • Lower reactivity
  • less water
  • lower pH
  • Reduced solubility of heavy metals
  • less mobile salts
  • Greater durability.
  • Denser.
  • Impermeable (tec-cements).
  • Dimensionally more stable with less shrinkage and
    cracking.
  • Homogenous.
  • No bleed water.

TecEco Technology - Converting Waste to Resource
61
Using Localized Low Transport Embodied Energy
Aggregates and Wastes to Make TecEco Cement
Concretes
  • As the price of fuel rises, theuse of on site
    low embodiedenergy materials ratherthan carted
    aggregates willhave to be considered.

No longer an option?
Recent natural disasters such as the recent
tsunami and Pakistani earthquake mean we urgently
need to commercialize TecEco technologies because
they provide benign environments allowing the use
of many local materials and wastes without
delayed reactions
62
Improve the Performance of Concrete by Including
Aggregates that Improve or Introduce New
Properties Reducing Lifetime Energies
  • Rather than be taken to landfill many wastes can
    be used to improve properties of concrete that
    reduce lifetime energies.
  • For example paper and plastic have in common
    reasonable tensile strength, low mass and low
    conductance and can be used to make cementitious
    composites that assume these properties
  • It follows that we can recycle for physical
    property.
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