Implementing Sustainability

1
Implementing Sustainability
Presentation by John Harrison, managing director
of TecEco and inventor of Tec and Eco-Cements and
the CarbonSafe process.
TecEco are in the biggest business on the planet
that of solving global warming waste and water
problems
Our slides are deliberately verbose as most
people download and view them from the net.
Because of time constraints I will have to race
over some slides John Harrison B.Sc. B.Ec.
FCPA.
2
The Problem. We have a Planet in Crisis

• In the next 50 years it is crunch time for

• Fresh Water
• Global warming
• Energy
• Waste Pollution

• Are you thinking about it? Do you have an answer?

3
Fresh Water

• The amount of water in the world is finite. The
  number of us is growing quickly and our water use
  is growing more quickly.
• A third of the world's population lives in
  water-stressed countries. By 2025, this is
  expected to rise to two-thirds.
• The world's supply of fresh water is running out.
  Already one person in five has no access to safe
  drinking water.

4
Global Warming
Rises in the levels of carbon dioxide and other
gases (methane, water vapour)
Are causing a rapid rise in temperature
5
The Carbon Cycle and Emissions
Emissions from fossil fuels and cement production
are the cause of the global warming problem
Source David Schimel and Lisa Dilling, National
Centre for Atmospheric Research 2003
6
Energy Crisis
Peak Oil Production (Campell 2004) Most models of
oil reserves, production and consumption show
peak oil around 2010 (Campbell 2005) and serious
undersupply and rapidly escalating prices by
2025. It follows that there will be economic
mayhem unless the cement and concrete industry
acts now to change the energy base of their
products.
7
Waste Pollution
Waste releases methane, can cause ill health in
the area, leads to the contamination of land,
underground water, streams and coastal waters
(destroying our fisheries) and gives rise to
various nuisances including increased traffic,
noise, odours, smoke, dust, litter and pests.
Most damaging is the release of dangerous
molecules to the global commons
There are various estimates, but we produce about
5-600 million tonnes of waste each year.
8
Ecological 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
TO SURVIVE
9
All these Problems Represent an Opportunity to Do
Something About Them

• 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.)
• 40-50 of waste that goes to landfill (15 of
  new materials going to site are wasted.)
• Over 30 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.
• And include many toxic elements.
• The single biggest materials flow (after water)
  is concrete at around 15 billion tonnes or gt 2
  tonnes per man, woman and child on the planet.

10
How? - The 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.
11
Under Materials Flows in the Techno-Processes are
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.
12
There are Detrimental Affects Right Through the
Techno-process
Detrimental Linkages that affect earth system
flows
Take manipulate and make impacts
End of lifecycle impacts
Materials are in the Techno-sphere Utility zone
There is no such place as away
Materials are everything between the take and
waste and affect earth system flows.
13
We Must Learn from Nature (Biomimicry)

• Nature is very efficient. The waste from one
  plant or animal is the food or home for another.
• By studying Nature we learn who we are, what we
  are and how we are to be. (Wright, F.L.
  1957269)
• In nature photosynthesis balances respiration.
• We have nothing that balances our emissions in
  the techno-process
• There is a strong need for similar efficiency and
  balance

By learning from Nature we can all live together
14
Biomimicry

• 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.
Nature is very economical about all Processes. We
must also be MUCH more economical
15
Economically Driven Sustainability
The challenge is to harness human behaviours
which underlay economic supply and demand
phenomena by changing the technical paradigm in
favour of making carbon dioxide and other wastes
resources for new materials with lower take and
waste impacts and more energy efficient
performance.
- ECONOMICS -
Sustainable processes are more efficient and
therefore more economic. Natural ecosystems can
be 100 efficient. What is needed are new
technologies that allow material and energy flows
to more closely mimic natural ecosystems. Innovati
on will deliver these new technical paradigms.
Sustainability will not happen by relying on
people to do the right thing
16
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.

One aspect of sustainability is that it is where
Culture and Technology meet.
17
Changing the Technology Paradigm
We need materials that require less energy to
make them, that last much longer and that
contribute properties that reduce lifetime
energies. The key is to change the technology
paradigm

• 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

18
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.
19
The TecEco CarbonSafe Industrial Ecology
InputsBrinesWaste AcidCO2
OutputsGypsum, Sodium bicarbonate, Salts,
Building materials, Potable water
We must design whole new technical paradigms that
reverse many of our problem molecular flows
20
A Low Energy Post Carbon Waste Age?
Maybe then we can move confidently into a more
sustainable future.
The construction industry can be uniquely
responsible for helping achieve this transition
21
Innovative New Materials - the Key to
Sustainability
The choice of materials controls emissions,
lifetime and embodied energies, user comfort, use
of recycled wastes, durability, recyclability and
the properties of wastes returned to the
bio-geo-sphere.
There is no such place as away, only a global
commons
22
Re - Engineering Materials What we Build With

• To solve environmental problems we need to
  understand more about materials in relation to
  the environment.
• the way their precursors are derived and their
  degradation products re assimilated
• and how we can reduce the impact of these
  processes
• what energies drive the evolution, devolution and
  flow of materials
• 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
inherently flawed materials, materials flows and
energy systems
23
Changing the Techno-process
Take gt manipulate gt make gt use gt waste Driven
by fossil fuel energy with detrimental effects on
earth systems.
ReduceRe-useRecycle
Eco-innovate
Materials
Improving the sustainability of materials used to
create the built environment will reduce the
impact of the take and waste phases of the
techno-process
24
Huge Potential for Sustainable Materials

• 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
25
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
26
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
27
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)
28
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)
29
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.
30
Cement Production Carbon Dioxide Emissions
Between tec, eco and enviro-cements TecEco can
provide a viable much more sustainable
alternative.
31
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
32
TecEco Binder Systems
SUSTAINABILITY
PORTLAND
POZZOLAN
Hydration of the various components of Portland
cement for strength.
Reaction of alkali with pozzolans (e.g. lime with
fly ash.) for sustainability, durability and
strength.
TECECO CEMENTS
DURABILITY
STRENGTH
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.
REACTIVE MAGNESIA
Hydration of magnesia gt brucite for strength,
workability, dimensional stability and
durability. In Eco-cements carbonation of brucite
gt nesquehonite, lansfordite and an amorphous
phase for sustainability.
33
TecEco Formulations

• Tec-cements (5-15 MgO, 85-95 OPC)
• 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 affective.
  After all the Portlandite has been consumed
  Brucite controls the long term pH which is lower
  and due to its 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 (15-95 MgO, 85-5 OPC)
• 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 (5-15 MgO, 85-95 OPC)
• 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.

34
Tec Eco-Cement Theory

• Many Engineering Issues are Actually
  Mineralogical Issues
• Problems with Portland cement concretes are
  usually resolved by the band aid engineering
  fixes. e.g.
• Use of calcium nitrite, silanes, cathodic
  protection or stainless steel to prevent
  corrosion.
• Use of coatings to prevent carbonation.
• Crack control joins to mitigate the affects of
  shrinkage cracking.
• Plasticisers to improve workability.
• Portlandite and water are the weakness of
  concrete
• TecEco remove Portlandite it and replacing it
  with magnesia which hydrates to Brucite.
• The hydration of magnesia consumes significant
  water

35
Tec Eco-Cement 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 significant water and
  concentrating alkalis forming Brucite which is
  another alkali, but much less soluble, mobile or
  reactive than Portlandite.
• In Eco-Cements brucite carbonates forming
  hydrated compounds with greater volume

36
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
37
Strength with Blend Porosity
Tec-cement concretes
Eco-cement concretes
High Porosity
Enviro-cement concretes
High OPC
High Magnesia
STRENGTH ON ARBITARY SCALE 1-100
38
TecEco Technology in Practice
gt 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.

39
TecEco Technology in Practice
gt Porous Pavement
Allow many mega litres of good fresh water to
become contaminated by the pollutants on our
streets and pollute coastal waterways
Or
Capture and cleanse the water for our use?
40
TecEco Technology in Practice
gt Whittlesea, Vic. Australia

• First Eco-cement mud bricks and mortars in
  Australia
• Tested up twice as strong as the PC controls
• Mud brick addition rate 2.5
• Addition rate for mortars 18 not 13 because of
  molar ratio volume increase with MgO compared to
  lime.

41
TecEco Technology in Practice
gt Earthship Brighton, UK
By 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.
Englands 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.
42
TecEco Technology in Practice
gt Clifton Surf Life Saving Club
The 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.
43
TecEco Technology in Practice
gt Mike Burdons Murdunna Works
Mike 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

44
TecEco Technology in Practice
gt DJ Motors, Hobart
Tec-Cement concretes exhibit little or no
shrinkage. At 10 substitution of MgO for PC the
shrinkage is less than half normal. At 18
substitution with no added pozzolan there was no
measurable shrinkage or expansion.
The above photo shows a tec-cement concrete
topping coat (with no flyash) 20mm thick away
from the door and 80 mm thick near the door. Note
that there has been no tendency to push the tiles
or shrink away from the borders as would normally
be the case.
45
TecEco Technology in Practice
gt Island Block and Paver,Tasmania
TecEco Tec and Eco-Cement blocks are now being
made commercially in Tasmania and with freight
equalization may be viable to ship to Victoria
for your green project. Hopefully soon we will
have a premix mortar available that uses
eco-cement.
46
TecEco Technology in Practice
gt Foamed Concretes
Foamed TecEco cement concretes can be produced to
about 30 weight reduction in concrete trucks
using cellflow additive or to about 70 weight
reduction using a foaming machine with mearlcrete
additive (or equivalents)
BUILD LITE CELLULAR CONCRETE4 Rosebank Ave 
Clayton Sth  MELBOURNE  AUSTRALIA 3169PH  61 3
9547 0255    FX  61 3 9547 0266
47
Tec Eco Cement Foamed Concrete Slabs
gt Foamed Concrete Slabs
BUILD LITE CELLULAR CONCRETE4 Rosebank Ave 
Clayton Sth  MELBOURNE  AUSTRALIA 3169PH  61 3
9547 0255    FX  61 3 9547 0266
48
TecEco Technology in Practice
gt Foamed Concretes Panels
Imagine a conventional steel frame section with a
foamed concrete panel built in adding to
structural strength, providing insulation as well
as the external cladding of a structure. Rigid
Steel Framing have developed just such a panel
and have chosen to use TecEco cement technology
for the strength, ease of use and finish. Patents
applied for by Rigid Steel Framing
Solutions in Steel ABN 48 103 573 039   TEL [phone]FAX [phone] Mica StreetCarole Park 4300QueenslandAustralia
Please direct commercial enquiries to Rigid Steel
Framing at rigidsteel.com.au
49
TecEco Technology in Practice
gt Foamed Concretes Panels
Rear view of test panels showing tongue and
groove and void for services.Interior
plasterboard is fixed conventionally over gap for
services.
50
Eco-Cements

• Eco-cements are similar but potentially superior
  to lime mortars because
• The calcination phase of the magnesium
  thermodynamic cycle takes place at a much lower
  temperature and is therefore more efficient.
• Magnesium minerals are generally more fibrous and
  acicular than calcium minerals and hence add
  microstructural strength.
• Water forms part of the binder minerals that
  forming making the cement component go further.
  In terms of binder produced for starting material
  in cement, eco-cements are much more efficient.
• Magnesium hydroxide in particular and to some
  extent the carbonates are less reactive and
  mobile and thus much more durable.

51
Eco-Cements

• Have high proportions of reactive magnesium oxide
• Carbonate like lime
• Generally used in a 15-112 paste basis because
  much more carbonate binder is produced than
  with lime
• MgO H2O ltgt Mg(OH)2
• Mg(OH)2 CO2 H2O ltgt MgCO3.3H2O
• 58.31 44.01 ltgt 138.32 molar mass (at least!)
• 24.29 gas 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)
• Carbonates tend to be fibrous adding significant
  micro structural strength compared to lime

Mostly CO2 and water
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.
52
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.
53
Eco-Cement Strength Development

• Eco-cements gain early strength from the
  hydration of PC.
• Later strength comes from the carbonation of
  brucite forming an amorphous phase, lansfordite
  and nesquehonite.
• Strength gain in eco-cements is mainly
  microstructural because of
• More ideal particle packing (Brucite particles at
  4-5 micron are under half the size of cement
  grains.)
• The natural fibrous and acicular shape of
  magnesium carbonate minerals which tend to lock
  together.
• More binder is formed than with calcium
• Total volumetric expansion from magnesium oxide
  to lansfordite is for example volume 811.

54
Eco-Cement Strength Gain Curve
Eco-cement bricks, blocks, pavers and mortars
etc. take a while to come to the same or greater
strength than OPC formulations but are stronger
than lime based formulations.
55
Chemistry of Eco-Cements

• There are a number of carbonates of magnesium.
  The main ones appear to be an amorphous phase,
  lansfordite and nesquehonite.
• The carbonation of magnesium hydroxide does not
  proceed as readily as that of calcium hydroxide.
• ?Gor Brucite to nesquehonite - 38.73 kJ.mol-1
• Compare to ?Gor Portlandite to calcite -64.62
  kJ.mol-1
• The dehydration of nesquehonite to form magnesite
  is not favoured by simple thermodynamics but may
  occur in the long term under the right
  conditions.
• ?Gor nesquehonite to magnesite 8.56 kJ.mol-1
• But kinetically driven by desiccation during
  drying.
• Reactive magnesia can carbonate in dry conditions
  so keep bags sealed!
• For a full discussion of the thermodynamics see
  our technical documents.

TecEco technical documents on the web cover the
important aspects of carbonation.
56
Eco-Cement Reactions
57
Eco-Cement Micro-Structural Strength
58
Carbonation

• 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.
• Magnesium is a small lightweight atom and the
  carbonates that form contain proportionally a lot
  of CO2 and water and are stronger because of
  superior microstructure.
• 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
59
Aggregate Requirements for Carbonation

• The requirements for totally hydraulic limes and
  all hydraulic concretes is to minimise the amount
  of water for hydraulic strength and maximise
  compaction and for this purpose aggregates that
  require grading and relatively fine rounded sands
  to minimise voids are required
• For carbonating eco-cements and lime mortars on
  the on the hand the matrix must breathe i.e.
  they must be porous
• requiring a coarse fraction to cause physical air
  voids and some vapour permeability.
• Coarse fractions are required in the aggregates
  used!

60
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.
61
TecEco Cement LCA
TecEco Concretes will have a big role post Kyoto
as they offer potential sequestration as well as
waste utilisation
The TecEco LCA model is available for download
under tools on the web site
62
Tec-Cement Reactions
MgO H2O gt Mg(OH)2.nH2O - water consumption
resulting in greater density and higher
alkalinity. Higher alkalinity gt more reactions
involving silica alumina. Mg(OH)2.nH2O gt
Mg(OH)2 H2O slow release water for more
complete hydration of PC MgO Al H2O gt
3MgO.Al.6H2O ??? equivalent to flash set?? MgO
SO4-- gt various Mg oxy sulfates ?? yes but
more likely ettringite reaction consumes SO4--
first. MgO SiO2 gt MSH ?? Yes but high
alkalinity required. Strength??
We think the reactions are relatively independent
of PC reactions
63
The Form of MgO Matters - 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 )

64
More Rapid and Greater Strength
DevelopmentHigher Strength Binder Ratio

• Concretes are more often than not made to
  strength.
• The use of tec-cement results in
• 15-30 more 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

Early strength gain with less cement and added
pozzolans is of great economic and environmental
importance as it will allow the use of more
pozzolans.
We have observed this sort of curve in over 500
cubic meters of concrete now
65
Tec-Cement Strength Development
Graphs above by Oxford Uni Student are for
standard 1PC3 aggregate mixes, w/c .5
WHITTLESEA SLAB (A modified 20 mpa mix) PC 180
Kg / m3MgO 15 Kg / m3Flyash 65 Kg / m3
Rate of strength development is of great interest
to engineers and constructors
66
Calorimetric Evidence of Faster Strength Gain
Faster Strength Development
Evolution of Less Heat
Energy associated with complexing?
67
Reasons for Compressive Strength Development in
Tec-Cements.

• Reactive magnesia requires considerable water to
  hydrate resulting in
• Denser, less permeable concrete. Self compaction?
• A significantly lower voids/paste ratio.
• Higher early pH initiating more effective
  silicification reactions?
• The Ca(OH)2 normally lost in bleed water is used
  internally for reaction with pozzolans.
• Super saturation of alkalis caused by the removal
  of water?
• Micro-structural strength due to particle packing
  (Magnesia particles at 4-5 micron are a little
  over ½ the size of cement grains.)
• Formation of MgAl hydrates? Similar to flash set
  in concrete but slower??
• Formation of MSH??
• Slow release of water from hydrated Mg(OH)2.nH2O
  supplying H2O for more complete hydration of C2S
  and C3S?

Brucite gains weight in excess of the theoretical
increase due to MgO conversion to Mg(OH)2 in
samples cured at 98 RH. Dr Luc Vandepierre,
Cambridge University, 20 September, 2005.
68
Greater Tensile Strength










Cement

Sand
MgO









Mutual Repulsion
gt
Mutual Repulsion
Ph 12 ?


-



-


-
Cement
-
Sand
MgO


-

-
-




Mutual Attraction
MgO Changes Surface Charge as the Ph Rises. This
could be one of the reasons for the greater
tensile strength displayed during the early
plastic phase of tec-cement concretes. The affect
of additives is not yet known
69
Durability

• Concretes are said to be less durable when they
  are physically or chemically compromised.
• Physical factors can result in chemical reactions
  reducing durability
• E.g. Cracking due to shrinkage can allow reactive
  gases and liquids to enter the concrete
• Chemical factors can result in physical outcomes
  reducing durability
• E.g. Alkali silica reaction opening up cracks
  allowing other agents such as sulfate and
  chloride in seawater to enter.
• This presentation will describe benchmark
  improvements in durability as a result of using
  the new TecEco magnesia cement technologies

70
Crack Collage
Alkali aggregateReaction
EvaporativeCrazingShrinkage
DryingShrinkage
Thermal
Settlement Shrinkage
Freeze Thaw D Cracks
Structural
PlasticShrinkage
Photos from PCA and US Dept. Ag Websites
Corrosion Related
Autogenous or self-desiccation shrinkage(usually
related to stoichiometric or chemical shrinkage)

• TecEco technology can reduce if not solve
  problems of cracking
• Related to (shrinkage) through open system loss
  of water.
• As a result of volume change caused by delayed
  reactions
• As a result of corrosion.
• Related to autogenous shrinkage

71
Causes of Cracking in Concrete

• Cracking commonly occurs when the induced stress
  exceeds the maximum tensile stress capacity of
  concrete and can be caused by many factors
  including restraint, extrinsic loads, lack of
  support, poor design, volume changes over time,
  temperature dependent volume change, corrosion or
  delayed reactions.
• Causes of induced stresses include
• Restrained thermal, plastic, drying and
  stoichiometric shrinkage, corrosion and delayed
  reaction strains.
• Slab curling.
• Loading on concrete structures.
• Cracking is undesirable for many reasons
• Visible cracking is unsightly
• Cracking compromises durability because it allows
  entry of gases and ions that react with
  Portlandite.
• Cracking can compromise structural integrity,
  particularly if it accelerates corrosion.

72
Graphic Illustration of Cracking
Autogenous shrinkage has been used to refer to
hydration shrinkage and is thus stoichiometric
After Tony Thomas (Boral Ltd.) (Thomas 2005)
73
Cracking due to Loss of Water
Brucite gains weight in excess of the theoretical
increase due to MgO conversion to Mg(OH)2 in
samples cured at 98 RH. Dr Luc Vandepierre,
Cambridge University, 20 September, 2005.
DryingShrinkage
Fool
PlasticShrinkage
EvaporativeCrazingShrinkage
Bucket of Water
Settlement Shrinkage
Picture from http//www.pavement.com/techserv/ACI
-GlobalWarming.PDF
We may not be able to prevent too much water
being added to concrete by fools.TecEco approach
the problem in a different way by providing for
the internal removal/storage of water that can
provide for more complete hydration of PC.
74
Solving Cracking due to Shrinkage from Loss of
Water

• In the system water plus Portland cement powder
  plus aggregates shrinkage is in the order of .05
  1.5 .
• Shrinkage causes cracking
• There are two main causes of Portland cements
  shrinking over time.
• Stoichiometric (chemical) shrinkage and
• Shrinkage through loss of water.
• The solution is to
• Add minerals that compensate by
  stoichiometrically expanding and/or to
• Use less water, internally hold water or prevent
  water loss.
• TecEco tec-cements internally hold water and
  prevent water loss.

MgO (s) H2O (l) ? Mg(OH)2.nH2O (s)
75
Preventing Shrinkage through Loss of Water

• When magnesia hydrates it consumes 18 litres of
  water per mole of magnesia probably more
  depending on the value of n in the reaction
  below
• MgO (s) H2O (l) ? Mg(OH)2.nH2O
  (s)
• The dimensional change in the system MgO PC
  depends on
• The ratio of MgO to PC
• Whether water required for hydration of PC and
  MgO is coming from stoichiometric mix water (i.e.
  the amount calculated as required), excess water
  (bleed or evaporative) or from outside the
  system.
• In practice tec-cement systems are more closed
  and thus dimensional change is more a function of
  the ratio of MgO to PC
• As a result of preventing the loss of water by
  closing the system together with expansive
  stoichiometry of MgO reactions (see below).
• MgO (s) H2O (l) ? Mg(OH)2.nH2O (s)
• 40.31 18.0 ? 58.3 molar mass (at
  least!)
• 11.2 liquid ? 24.3 molar
  volumes (at least!)
• It is possible to significantly reduce if not
  prevent (drying, plastic, evaporative and some
  settlement) shrinkage as a result of water losses
  from the system.

The molar volume (L.mol-1)is equal to the molar
mass (g.mol-1) divided by the density (g.L-1).
76
Preventing Shrinkage through Loss of Water

• Portland cements stoichiometrically require
  around 23 -27 water for hydration yet we add
  approximately 45 to 60 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 internally in a closed system in a
  similar way.

MgO (s) H2O (l) ? Mg(OH)2.nH2O (s)
77
Other Benefits of Preventing Shrinkage through
Loss of Water

• Internal water consumption also results in
• Greater strength
• More complete hydration of PC .
• Reduced in situ voidspaste ratio
• Greater density
• Increased durability
• Higher short term alkalinity
• More effective pozzolanic reactions.
• More complete hydration of PC .
• Small substitutions of PC by MgO result in water
  being trapped inside concrete as Brucite and
  Brucite hydrates which can later self desiccate
  delivering water to hydration reactions of
  calcium silicates (Preventing so called
  Autogenous shrinkage).

78
Bleeding is a Bad Thing

• Bleeding is caused by
• Lack of fines
• Too much water
• Bleeding can be fixed by
• Reducing water or adding fines
• Air entrainment or grading adjustments
• Bleeding causes
• Reduced pumpability
• Loss of cement near the surface of concretes
• Delays in finishing
• Poor bond between layers of concrete
• Interconnected pore structures that allow
  aggressive agents to enter later
• Slump and plastic cracking due to loss of volume
  from the system
• Loss of alkali that should remain in the system
  for better pozzolanic reactions
• Loss of pollutants such as heavy metals if wastes
  are being incorporated.
• Concrete is better as a closed system

Better to keep concretes as closed systems
79
Dimensional Control in Tec-Cement Concretes over
Time

• By adding MgO volume changes are minimised to
  close to neutral.
• So far we have observed significantly less
  shrinkage in TecEco tec - cement concretes with
  about (8-10 substitution OPC) with or without
  fly ash.
• At some ratio, thought to be around 15-18
  reactive magnesia there is no shrinkage.
• The water lost by concrete as it shrinks is used
  by the reactive magnesia as it hydrates
  eliminating shrinkage.
• Note that brucite is gt 44.65 mass water and it
  makes sense to make binders out of water!
• More research is required to accurately establish
  volume relationships and causes for reduced
  shrinkage.

80
Long Term pH control

• TecEco add reactive magnesia which hydrates
  forming brucite which is another alkali, but much
  less soluble, mobile or reactive than
  Portlandite.
• Brucite provides long term pH control.

A pH in the range 10.5 11.2 is ideal in a
concrete
81
Reducing Cracking as a Result of Volume Change
caused by Delayed Reactions
An Alkali Aggregate Reaction Cracked Bridge
Element
Photo Courtesy Ahmad Shayan ARRB
82
Types of Delayed Reactions

• There are several types of delayed reactions that
  cause volume changes (generally expansion) and
  cracking.
• Alkali silica reactions
• Alkali carbonate reactions
• Delayed ettringite formation
• Delayed thaumasite formation
• Delayed hydration or dead burned lime or
  periclase.
• Delayed reactions cause dimensional distress,
  cracking and possibly even failure.

83
Reducing Delayed Reactions

• Delayed reactions do not appear to occur to the
  same extent in TecEco cements.
• A lower long term pH results in reduced
  reactivity after the plastic stage.
• Potentially reactive ions are trapped in the
  structure of brucite.
• Ordinary Portland cement concretes can take years
  to dry out however the reactive magnesia in
  Tec-cement concretes consumes unbound water from
  the pores inside concrete.
• Magnesia dries concrete out from the inside.
  Reactions do not occur without water.

84
Reduced Steel Corrosion Related Cracking
Rusting Causes Dimensional Distress

• Steel remains protected with a passive oxide
  coating of Fe3O4 above pH 8.9.
• A pH of over 8.9 is maintained by the equilibrium
  Mg(OH)2 ? Mg 2OH- for much longer than the pH
  maintained by Ca(OH)2 because
• Brucite does not react as readily as Portlandite
  resulting in reduced carbonation rates and
  reactions with salts.
• Concrete with brucite in it is denser and
  carbonation is expansive, sealing the surface
  preventing further access by moisture, CO2 and
  salts.

85
Reduced Steel Corrosion

• Brucite is less soluble and traps salts as it
  forms resulting in less ionic transport to
  complete a circuit for electrolysis and less
  corrosion.
• Free chlorides and sulfates originally in cement
  and aggregates are bound by magnesium
• Magnesium oxychlorides or oxysulfates are formed.
  ( Compatible phases in hydraulic binders that are
  stable provided the concrete is dense and water
  kept out.)
• As a result of the above the rusting of
  reinforcement does not proceed to the same
  extent.
• Cracking or spalling due to rust does not occur

86
Steel Corrosion is Influenced by Long Term pH
In TecEco cements the long term pH is governed by
the low solubility and carbonation rate 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. The pH
is still high enough to keep Fe3O4 stable in
reducing conditions.
Eh-pH or Pourbaix Diagram The stability fields of
hematite, magnetite and siderite in aqueous
solution total dissolved carbonate 10-2M.
Steel corrodes below 8.9
Equilibrium pH of Brucite and of lime
87
Reducing Cracking Related to Autogenous Shrinkage

• Autogenous shrinkage tends to occur in high
  performance concretes in which dense
  microstructures develop quickly preventing the
  entry of additional water required to complete
  hydration.
• First defined by Lynam in 1934 (Lynam CG. Growth
  and movement in Portland cement concrete. London
  Oxford University Press 1934. p. 26-7.)
• The autogenous deformation of concrete is defined
  as the unrestrained, bulk deformation that occurs
  when concrete is kept sealed and at a constant
  temperature.

88
Reducing Cracking Related to Autogenous Shrinkage

• Main cause is stoichiometric or chemical
  shrinkage as observed by Le Chatelier.
• whereby the reaction products formed during the
  hydration of cement occupy less space than the
  corresponding reactants.
• A dense cement paste hydrating under sealed
  conditions will therefore self-desiccate creating
  empty pores within developing structure. If
  external water is not available to fill these
  empty pores, considerable shrinkage can result.

Le Chatelier H. Sur les changements de volume qui
accompagnent Ie durcissement des ciments.
Bulletin de la Societe d'Encouragement pour
I'Industrie Nationale 190054-7.
89
Reducing Cracking Related to Autogenous Shrinkage

• Autogenous shrinkage does not occur in high
  strength tec-cement concretes because
• The brucite hydrates that form desiccate back to
  brucite delivering water in situ for more
  complete hydration of Portland cement.
• Mg(OH)2.nH2O (s) ? MgO (s) H2O (l)
• As brucite is a relatively weak mineral
  compressed and densifies the microstructure.
• The stoichiometric shrinkage of Portland cement
  (first observed by Le Chatelier) is compensated
  for by the stoichiometric expansion of magnesium
  oxide on hydration.
• MgO (s) H2O (l) ? Mg(OH)2.nH2O (s)
• 40.31 18.0 ? 58.3 molar mass (at least!)
• 11.2 liquid ? 24.3 molar volumes (at least
  116 expansion, probably more initially before
  desiccation as above!)

90
Improved Durability
Materials that last longer need replacing less
often saving on energy and resources.

• Reasons for Improved Durability
• Greater Density Lower Permeability
• Physical Weaknesses gt Chemical Attack
• Removal of Portlandite with the Pozzolanic
  Reaction.
• Removal or reactive components
• Substitution by Brucite gt Long Term pH control
• Reducing corrosion

91
Reduced Permeability

• As bleed water exits ordinary Portland cement
  concretes it creates an interconnected pore
  structure that remains in concrete allowing the
  entry of aggressive agents such as SO4--, Cl- and
  CO2
• TecEco tec - cement concretes are a closed
  system. They do not bleed as excess water is
  consumed by the hydration of magnesia.
• As a result TecEco tec - cement concretes dry
  from within, are denser and less permeable and
  therefore stronger more durable and less
  permeable. Cement powder is not lost near the
  surfaces. Tec-cements have a higher salt
  resistance and less corrosion of steel etc.

92
Greater Density Lower Permeability

• Concretes have a high percentage (around 18
  22) of voids.
• On hydration magnesia expands gt116.9 filling
  voids and surrounding hydrating cement grains gt
  denser concrete.
• On carbonation to nesquehonite brucite expands
  307 sealing the surface.
• Lower voidspaste ratios than waterbinder ratios
  result in little or no bleed water, lower
  permeability and greater density.

93
Densification 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.
94
Durability - Reduced Salt Acid Attack

• 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 it is a
  least 5 orders of magnitude less soluble, mobile
  or reactive.
• Ksp brucite 1.8 X 10-11
• Ksp Portlandite 5.5 X 10-6
• TecEco cements are more acid resistant than
  Portland cement
• This is because of the relatively high acid
  resistance (?) of Lansfordite and nesquehonite
  compared to calcite or aragonite

95
Less Freeze - Thaw Problems

• Denser concretes do not let water in.
• Brucite will to a certain extent take up internal
  stresses
• When magnesia hydrates it expands into the pores
  left around hydrating cement grains
• MgO (s) H2O (l) ? Mg(OH)2 (s)
• 40.31 18.0 ? 58.3 molar
  mass
• 11.2 18.0 ? 24.3 molar
  volumes
• 39.20 ? 24.3 molar volumes
• At least 38 air voids are created in space that
  was occupied by magnesia and water!
• Air entrainment can also be used as in
  conventional concretes
• TecEco concretes are not attacked by the salts
  used on roads

96
Rosendale Concretes Proof of Durability

• Rosendale cements contained 14 30 MgO
• A major structure built with Rosendale cements
  commenced in 1846 was Fort Jefferson near key
  west in Florida.
• Rosendale cements were recognized for their
  exceptional durability, even under severe
  exposure. At Fort Jefferson much of the 150
  year-old Rosendale cement mortar remains in
  excellent condition, in spite of the severe ocean
  exposure and over 100 years of neglect. Fort
  Jefferson is nearly a half mile in circumference
  and has a total lack of expansion joints, yet
  shows no signs of cracking or stress. The first
  phase of a major restoration is currently in
  progress.

More information from http//www.rosendalecement.n
et/rosendale_natural_cement_.html
97
Solving Waste Logistics Problems

• TecEco cementitious composites represent a cost
  affective 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.