Transcript Slide 1

Pervious Pavement
“We can't solve problems by using the same kind of thinking we used
when we created them." Albert Einstein. Pervious Pavements are a
different way of thinking about roads.
John Harrison, B.Sc. B.Ec. FCPA
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What Is Pervious Pavement?
 Pervious pavement is a permeable pavement surface with a
stone reservoir underneath.
 The reservoir temporarily stores surface runoff before
infiltrating it into the subsoil or sub-surface drainage and in
the process improves the water quality.
 Permeable materials such as ancient lime mortars and
pervious pavements are made using relatively mono graded
materials.
 Pervious pavements allow the earth to breathe, take in
water and be healthy. The stone and soil under them acts as
a reservoir and cleans the water just like the filter on a fish
tank.
 Pervious pavements are safer to drive on as they do not
develop "puddles", have a good surface to grip
 Subdivisions made with pervious pavement that also have
street trees can be several degrees cooler than
surrounding suburbs without.
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The Water Cycle
The water or hydrological cycle is
powered by the sun and water
changes state and is stored as it
moves through it.
Human intervention is reducing the
time it takes for water to return to
the oceans resulting in less
moisture on land, salinity and
aridity.
Source:Illustration by John M. Evans USGS, Colorado District (http://ga.water.usgs.gov/edu/watercyclegraphichi.html)
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Australia Before Settlement
In years
gone by
grassland
and forest
covered the
land
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Our Legacy
 In years gone by forests and grassland covered most of our
planet.
– When it rained much of the water naturally percolated though soils that
performed vital functions of
• slowing down the rate of transport to rivers and streams,
• purifying the water and
• replenishing natural aquifers.
 Our legacy has been to pave this natural bio filter, redirecting
the water that fell as rain as quickly as possible to the sea.
 Given global water shortages, problems with salinity, pollution,
volume and rate of flow of runoff we need to change our
practices so as to mimic the way it was for so many millions of
years before we started making so many changes.
 The key to survival in the future will be learning from nature
and mimicking her subtle processes. Road are the arteries,
veins and lymphatic system to cities.
 This presentation focuses on where we have gone wrong with
roads and the radical TecEco Permecocrete solution.
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Australia with a Little Lateral Thinking & Effort
TecEco technology provides ways of
sequestering carbon dioxide and utilising
wastes to create our techno - world
Less paper.
Other Cl free
processes - no
salinity
Evolution
away from
using trees –
paperless
office
Vehicles – more
efficient and using
fuel cells
Cows – CSIO
anti methane
bred
Organic farming
Carbon returned to
soils.
Pervious pavements prevent
immediate and polluted run-off.
Carbon dioxide and other gases
absorbed by TecEco EcoCements. Sewerage converted to
fertilizer and returned to soils.
Buildings generate own energy
etc.
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It is
essential
we learn to
live with
nature and
change our
ways6
One Planet, Many People, Many Interconnected Problems
Global Sustainability
Alliance Partners are in the
BIGGEST Business on the
Planet – Economic
Solutions to our Energy,
Global Warming, Water
and Waste Problems.
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7
Global Fresh Water
A finite resource
– Population rising
– Per capita use rising
Water-stress
– 1/3 world's population
– By 2025, 2/3 due to global warming.
– 1 person in 5 do not have access to safe drinking
water
Yet water is the most common substance on
the planet.
– Water covers 70% of the surface
– Only =~ 1% is potable
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Australia’s Water Problems
 Australia is the driest inhabited continent in
the world - only Antarctica gets less rain.
 Most of Australia has experienced drought
under El Nino conditions for the past few
years.
 Some major cities are seriously short of
water.
 Yet giga litres of stormwater go into our
coastal water ways every year carrying with
it significant levels of pollution.
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Stormwater = Rainwater + Pollution
 Pollution comes from many different
sources, however the two main sources are
Point and Non-point sources.
 Stormwater is the major cause of reduction
in water quality in rivers and the destruction
of marine environments.
 Stormwater is NOT supposed to include
sewerage!
 Pollution is why it is not a good idea to eat
too many fish from many areas near cities
Why mix rainwater and pollution?
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Point and Non-Point Source Pollution
 Point Source Pollution
Point source pollution is when high levels of
pollution enter a water system such as a wetland or
river from one source, such as a factory, mine,
sewage plant or garbage dump. Point source
pollution is easy to trace.
 Non-Point Source Pollution
Non-point source pollution is when levels of
pollution enter a water system at various points and
from various sources. This type of pollution is the
most difficult to monitor and manage. The most
common non-point source of stormwater pollution
comes from local residents throughout a catchment.
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Stormwater = Rainwater + Pollution
Source: thesource.melbournewater.com.au/.../river.htm
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Sources and Types of Pollution
Land uses
Types of pollution
Rural/agricultural &market Silt, pesticides, fertilisers, livestock
gardens faeces.
Residential properties & gardens
Detergent, pesticides, fertiliser, dog
faeces, leaf litter.
Industrial areas Industrial runoff & acidity
Roads & carparks Oil, petrol, heavy metals, leaf litter
Shopping centres
Litter, shopping bags, junk food
containers
Service stations Detergents, oil, petrol
Construction/building sites Silt, paint, packaging, bricks
Sewage treatment plant Bacteria, phosphorus, nitrates
Parks and reserves
Litter, dog and cat faeces, grass
cuttings, leaves
Adapted from: www.cwmb.sa.gov.au/kwc/section1/1-24.htm
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Types of Pollution (1)
Litter Pedestrians dropping food wrappers , cigarette butts etc.
Motorists tossing litter from their vehicles. Litter from building sites.
Industry packaging and other waste materials. Trucks with
uncovered loads which blows onto roads.
Macro
Leaves Deciduous trees drop their leaves in Autumn creating a
significant pollution problem in the waterways. Excessive leaves
enter the stormwater system, choking waterways, reducing sunlight
penetration and decomposing, causing nitrate pollution. This can
create low oxygen conditions, killing animals.
Macro
Micro and
Molecular
Sediment Sediment is a major source of pollution in stormwater.
Excessive sediment chokes creek beds and reduces flow capacity
as well as de- grading natural ecosystems by stifling aquatic plants
and animals and blocking sunlight. Sources include construction
sites, erosion along streams and rivers, soil erosion from poor
management of agricultural activities, and road runoff.
Micro
Soaps and detergents Detergent and soaps tend to contain high
levels of phosphorus. This chemical is a limiting factor in plant
growth. Excessive amounts provide the nutrients required to fuel an
algal bloom.
Molecular
Modified from: EPA stormwater code of practice from
www.cwmb.sa.gov.au/kwc/section1/1-24.htm
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Types of Pollution (2)
Oil and grease Enter the stormwater system via leaking engines,
deliberate dumping and accidental spills. High levels of oil can
directly threaten the life of animals in waterways.
Macro and
Molecular
Nutrients Enter the stormwater system via runoff from parks and
farms that use fertiliser, effluent from sewage treatment plants and
septic tanks, chemical and fertiliser spills, and rotting vegetation.
Nutrients provide fuel for algal blooms which choke waterways, cut
off light and hence kill off aquatic ecosystems. Excessive nitrogen
is one of the major factors in the die back of seagrass in our rivers.
Molecular
Faecal coliforms Enter the stormwater system by contamination
with human or animal wastes. The main sources are dogs, horses,
septic tanks and farm animals.
Macro
Micro and
Molecular
Heavy Metals Lead, zinc and copper are the major heavy metals
entering the stormwater system via roads, and in the case of lead,
via exhaust. Elevated levels can cause death and mutation in animal
populations.
Molecular
Modified from: EPA stormwater code of practice from
www.cwmb.sa.gov.au/kwc/section1/1-24.htm
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Roads Interrupt Natural Drainage
 We have dissected the
landscape with roads
and no matter what kind,
they modify the drainage
network.
 Roads themselves are
impervious and also
capture water.
 Stormwater from
buildings and from
properties usually goes
to the same drainage
system.
 Stormwater = Rainwater
+ Pollution
Various
sources!
Source: Keith Stichler, CBF
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Roads are the Drainage Network
And represent a huge wasted catchment
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Impervious Watersheds Kill Rivers and Speed
up the Water Cycle
 There is a relationship between the amount of impervious
surface cover within a watershed and the quality of
surface water within that watershed.
– 10 to 15% of an area is covered by impervious surfaces, the
increased sediment and chemical pollutants in runoff have a
measurable effect on water quality.
– 15 to 25% of a watershed is paved or impervious to drainage,
increased runoff leads to reduced oxygen levels and harms stream
life.
– If more than 25% of surfaces are paved, many types of macro and
micro organisms in streams die from concentrated runoff and
sediments Smith, A. (2001). New Satellite Maps Provide Planners Improved Urban Sprawl
Insight, NASA Goddard Space Flight Center, GSFC on-line News Releases.
The more impervious the surface the more speed,
volume and pollution water acquires.
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Purifying Water
 Pervious pavements filter water falling on them releasing it
slowly to sub-surface drains or aquifers and finally the sea.
There is little or now surface run-off to carry rubbish into
drains and streams.
 Water quality is purified by the sub-pavement acting as a
giant biofiliter allowing bacteria and oxygen to do their work
and because surface rubbish does not contaminate it.
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Pervious Pavements Act Like a Giant Biofilter
 Just as fish cannot be kept in an
aquarium without a filter system
they are not healthy in our lakes
dams creeks and rivers without
natural or man made filtration of
run off water.
 Pervious pavements and their sub
structures act as a giant biofilters
 Pervious pavement with integral
bacteria improves water quality
entering aquifers, streams and
rivers.
 The critical "first flush" of
pollutants is sent rapidly into the
cross-section where constantly
available sources of bacteria and
microbes exist and have sufficient
Source Wikipedia. Filtration system in a typical aquarium: (1) air exchange capability to maintain
Intake. (2) Mechanical filtration. (3) Chemical filtration. (4)
themselves and perform their
Biological filtration medium. (5) Outflow to tank.
cleaning functions.
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Speed, Volume Sediment Load and Pollution
Rainwater does good
all the way to the
sea. Polluted and
salty water do no
good at all
Low speed, low
volume low distance
covered = low pollution
and salts
“The Water Dynamic”
Higher speed,
higher volume,
more energy,
greater distance
covered = more
pollution and salts
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Traps Do Not Stop Micro and Molecular Pollution
Source www.dpiw.tas.gov.au/.../RPIO4YJ3KA?open
Traps are
useless for
stopping most
pollutants other
than those that
are unsightly
www.azstorm.org/public_edu.php
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The Functions of Roads
 Roads are the veins, arteries and lymphatic system of
cities.
 They provide
– The network for
• The transport of resources and wastes
• Drainage
– The route for all services
•
•
•
•
•
Water
Sewerage
Electricity
Gas
Telephone etc.
 Many different people are involved
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Current Road Designs are Not Sustainable
Drainage and
Traffic Engineers
Sewerage
Engineers
Traffic
Engineers
Management
Hydraulic
Engineers
Environmental
Scientists
Gas
Engineers
Ratepayers
Telecommunication
Engineers
Geo Technical
Engineers
The various groups with an interest in
roads do not work together holistically
Electrical
Engineers
How often do you see the
same section of road dug
up repeatedly in quick
succession?
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Changing the Road Paradigm
 Roads and associated services as they are today have
not been thought out. They have evolved.
 In the past the agencies that are responsible for these
networks and services have more or less acted
independently of each other resulting in
– Wasted Resources
– Additional Cost
 How often do you see different crews digging up the
same bit of road?
– This is not sustainable!
You never change things by fighting the existing
reality. To change something, build a new model
that makes the existing model obsolete. –
Buckminster Fuller
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Building a New Model
 The engineering paradigm too prevalent amongst the road
building fraternity is:
– “Roads are for vehicles” “water on roads in dangerous” “collect it and
get rid of it as quickly as possible”
 Given the current water crisis can this limited thinking be
allowed to continue?
 Only a small % of water reticulated through a community is
used for drinking.
– Most is used for washing, laundry, flushing toilets or watering gardens.
 Perhaps the water caught by our road drainage systems
could be used?
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Heads First for Action
 Water, CO2, waste and many other
issues are mostly in our heads.
– We must first think differently then
– Act differently!
 Roads are not just for traffic
–
–
–
–
They set drainage patterns
Carry services under them
Define wildlife zones
Prevent natural percolation to aquifers
etc.
 Roads in the future will have to be:
– Holistically designed
– Take into account previously
unintended outcomes such as local
drainage alteration and pollution.
– Capture desperately needed water
 Our model, measure and mentor for
change must be nature.
John Harrison with pervious pavement.
Photographer Peter Boyer
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Our Guide - Biomimicry - Geomimicry
 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.
 Geomimicry is similar to biomimicry but models geological
rather than biological processes.
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 and very little of energy.
Geomimicry is a natural extension of biomimicry and applies to
geological rather than living processes
We can learn from nature about how
we should construct roads
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Pervious Concrete Pavement - Addressing the Issues
Pervious pavement is a unique and effective means of addressing
environmental issues
Image source: http://www.perviouspavement.org/
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TecEco Permecocrete - Thinking About Water and Roads
Pavements are not just for
vehicles. They must do
much more
CO2
CO2
CO2
CO2
CO2
CO2
Sequestration
Cleansing microbial activity
and oxygenation
Cooling
Evaporation
Moisture
retention
The substrate must be
properly designed
Optional groundwater
recharge
Optional impervious layer, underground
drainage and storage. Dual water supply or
parks etc. only.
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Holistic Roads for the Future
In Australia we run many duplicate services down each side of
a road. Given the high cost of installing infrastructure it would
be smarter to adopt a system whereby services run down the
middle of a road down what amount to giant box culverts.
Conventional
bitumen or
concrete footpath
pavement
Pervious EcoCement concrete
pavement
(Permecocrete)
surface using
recycled
aggregates
Possible leakage
to street trees
and underground
aquifers
Services to either
side of the road.
All in same trench
of conduit
Impermeable
layer (concrete or
plastic liner)
angling for main
flow towards
collection drains
Service conduit
down middle of
road
Collection drains to
transport drain or
pipe in service
conduit at intervals
Pervious gravel
under for
collection,
cleansing and
storage of water
Foamed Eco-Cement concrete
root redirectors and pavement
protectors. Roots will grow away
from the foamed concrete
because of its general alkalinity.
It will also give to some extent
preventing surface pavement
cracking.
Its time for a road re think!
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TecEco Eco-Cement Permecocrete
- Mimicking Nature
Water feature
keeps water clean
All rainwater redirected to pavement filter.
Permecocrete pervious
pavement
Pump
Water storage
e.g. under drive
 Permecocrete is made
with Eco-Cements that
set by absorbing CO2
and can use recycled
aggregates. It does not
get any greener!
 Freedom from water
restrictions – forever!
 Pure fresh water from
your own block.
 Filtration through
Permecocrete and
water feature in garden
will keep water pure
and fresh.
 Cooler house and
garden (cycle under
slab for house
cooling/heating option).
 Lower infrastructure
costs for local council.
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Placing Pervious Pavement
Source: www.percocrete.com
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Finishing Pervious Pavement
Source: www.percocrete.com
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Laying Pervious Pavement
Source: www.percocrete.com
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Cross Section Pervious Pavement
Source: www.percocrete.com
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TecEco Permecocrete
 TecEco Eco-Cement Permecocrete concrete
pavement technology
– Is a unique and effective means to address important environmental
issues and support sustainable growth.
 Environmental Advantages
– Slows down the rate of transport to rivers and streams
• purifying water
• replenishing natural aquifers.
• Reducing salinity
– Eco-Cement Pervious concrete sequesters carbon dioxide
 Non Environmental Advantages
–
–
–
–
–
Safer for traffic
Improved acoustic properties
Reduces building maintenance
Cooler suburbs
Reduced drainage infrastructure costs
• Reduces the need for culverts, pies drains, retention ponds, swales, and
other storm water management devices.
– Less watering of street trees
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Environmental Advantages
 Reduced volume and rate of runoff
– Pervious pavement would allow the replenishment of aquifers and
reduced the cost of infrastructure to carry water out to sea as the
volume and rate of flow would be less. Not as many pollutants, rubbish
and debris would be transported reducing waterway pollution.
 Cleaner water - less pollution
– A pervious pavement with integral bacteria would improve water quality
entering aquifers, streams and rivers. The critical "first flush" of
pollutants would be sent rapidly into the cross-section where constantly
available sources of bacteria and microbes exist and have sufficient air
exchange capability to maintain themselves and perform their cleaning
functions. Pervious pavements could act as both pavements and biofilters at the same time.
 Replenish aquifers or provide water
– Reducing salinity by replenishment with fresh water.
 Permecocretes are also carbon sinks.
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Non Environmental Advantages
 Pervious pavements do not collect puddles of water making it
safer for traffic
 Pervious pavements are quieter as the absorb sound
 Pervious pavement prevent the ground drying out under
building cracking them.
 Pervious pavements made with TecEco Eco-Cements are
more durable
 Cities with pervious pavement are cooler
– They can transpire naturally (loosing latent heat of evaporation)
– Eco-Cement Permecocrete concrete pavement has a lighter albido
 Given economies of scale Tec-Eco Permecocrete pavement
should cost less
– Less infrastructure
• Reduced need for culverts, pipes, retention ponds, swales, and other
stormwater management devices
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Hot City Syndrome and Pervious Pavement
 Ever walked up a pebble beach on a hot sunny day? The heat
held by the stones can be unbearable! It’s the same in large
cities. There are so many materials with high specific heat
that during hot sunny weather and with no natural
transpiration, due to the fact that we have paved all the
ground, large cities just get hotter and hotter.
 As architects, engineers and designers of cities we need to
come to grips with the macro impacts of the materials we
use. Hot city syndrome is one of a number of man made
phenomena that the use of pervious Eco-Cement pavements
will reduce. The solution is to let the ground breathe and
pervious pavements do this. Evaporation after all is still the
principle behind many cooling systems – so why do we pave
the ground and prevent moisture entering or exiting?
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Collecting
Rain
Water
Using
Pervious
Solving the Water Problem
Pavement
 An unknown but huge quantity of water is drained away to
sea taking with it polluting substances and articles every
time it rains on our cities.
 This rapid drainage of rain requires a high cost of
investment in much larger drains than the original natural
drainage replaced because water no longer percolates
through natural vegetation and obstacles.
– In urban and some agricultural areas water gets to the sea in hours
not days!
 This water could be collected by permeable roads also
acting as giant bio filters, subterranean reservoirs (the city
of Alexandria had huge underground cisterns over 2000
years ago) and collection and redistribution network.
 An essential component of this paradigm is pervious
pavement.
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The Clogging Myth - Cleaning Pervious Pavement
Those who remain
sceptics please also
note that it is better to
have pollution collected
from a pervious
pavement by machinery
than pollute our coastal
waterways
Frimokar Australia high
pressure jet and suction
cleaning in action
The experience of many engineers is that with relatively minor control and
maintenance clogging will not reduce the infiltration rate below a design rate
within the lifecycle of the pavement. Like any other kind of surface, pervious
pavements should be cleaned periodically to remove debris and water under
pressure combined with suction is most effective.
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Making Pervious Pavement
 Ideally a pervious pavement should be made with monograded stone aggregates and a binder and be similar to
asphalt or concrete to handle and install.
– In cold areas it is important that the pavement should not trap water
otherwise in winter the water would freeze and cause cracking.
– It is also important to detail a permeable structural base and sub base
for the pavement that has a high void ratio as this acts as a reservoir,
and provide underground drainage as required.
Comparing Concrete Pervious Pavements to Asphalt
Eco-Cement Permecocrete
Pervious Pavement
Set by absorbing CO2
Can use recycled materials as long
as they are hard and mono-graded
Asphalt
Carcenogenic to workers using it.
Becoming more expensive as
petroleum supplies dwindle.
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Salinity
 Increasing salinity is one of the most significant environmental
problems facing Australia.
– While salt is naturally present in many of our landscapes, European
farming practices which replaced native vegetation with shallow-rooted
crops and pastures have caused a marked increase in the expression of
salinity in our land and water resources.
 Rising groundwater levels, caused by these farming practices,
are bringing with them dissolved salts which were stored in
the ground for millennia.
– Salt is being transported to the root-zones of remnant vegetation, crops,
pastures, and directly into our wetlands, streams and river systems. The
rising water tables are also affecting our rural infrastructure including
buildings, roads, pipes and underground cables.
– Salinity and rising water tables incur significant and costly impacts.
 According to the Australian National Action plan
(http://www.napswq.gov.au/publications/salinity.html#how)
and CSIRO web sites there are two main causes of salinity
– irrigation salinity
– dryland salinity
• Caused by clearing
• Caused by evaporation
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Irrigation Salinity
 According to the Australian National Action plan website at
http://www.napswq.gov.au/publications/salinity.html# how salinity
occurs through irrigation is because water soaks through the soil
area where the plant roots grow, adding to the existing water. The
additional irrigation water causes the underground water-table to
rise, bringing salt to the surface. When the irrigated area dries and
the underground water-table recedes, salt is left on the surface soil.
Each time the area is irrigated this salinity process is repeated.
 The government website quoted above fails to state the obvious
which is that:
– Every time water percolates through rocks and soil it picks up more salts. In the
Murray Darling system a lot of irrigation water returns on the surface and
underground to the river and is used again for irrigation, exacerbating the
problem
 The sequence forestry-agriculture-irrigation-salinity-aridity has
destroyed many civilisations – will ours be next?
Figure from the
Australian National
Action plan website
at
http://www.napswq.g
ov.au/publications/sal
inity.html#how
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Dryland Salinity – Caused by Clearing
 According to the Australian National Action plan website at
http://www.napswq.gov.au/publications/salinity.html#how
Dryland salinity is caused when the rising water-table brings
natural salts in the soil to the surface.
– The salt remains in the soil and becomes progressively concentrated as
the water evaporates or is used by plants.
– One of the main causes for rising water-tables is the removal of deep
rooted plants, perennial trees, shrubs and grasses and their
replacement by annual crops and pastures that do not use as much
water.
Figures from the Australian National Action plan website at
http://www.napswq.gov.au/publications/salinity.html#how
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Dryland Salinity – Caused by Evaporation
 Salinity also also develops as excess water moves to and collects in
poorly drained discharge zones. The buildup of excess water brings
dissolved salts to the surface where evaporation concentrates them.
Figure modified from the Manitoba Agriculture Web Site
www.gov.mb.ca/.../soilwater/soil/fbe01s06.html
Presentation downloadable from www.tececo.com
47
Salinity, Agricultural Practices and Pervious
Pavement
Native tree belts
TecEco
permecocrete
roads
Deep rooted salt tolerent species
(The PundaZoie company)
Salinity in
untreated
areas
Salinity in
untreated
areas
Contoured
swales
Deep drains
Salty water
Fresh water
 Salinity can be rectified by a combination of:
– Deep drainage.
– Mulching to increase humidity at ground level and reduce evaporative loss.
– Planting deep rooted salt tolerant species and leaving native belts that reduce
the overall rate of evapotranspiration of the fresh water lens on top of ground
water.
– Pervious rather than sealed surfaces (TecEco permecocrete pervious
pavement).
• Allowing capture of fresh water rather than run off.
– Maximising capture and use of fresh water and minimising irrigation water.
• Replenishing aquifers with fresh rain water rather than recycled water through
irrigation.
Presentation downloadable from www.tececo.com
48
How Our Theories Differ on Salinity
 Many websites including the CSIRO and Australian government
website on salinity when discussing salinity that is not clearly related
to irrigation and the re-use of water seem to think that the problem
relates to reduced evapotranspiration with agriculture and rising
water tables that bring “ancient” salts to the surface.
 We think this analysis wrong. When land is cleared natural mulches
and soil humus that retain water and reduce evaporation and rate of
run off at the surface of soils are removed.
 As a consequence what then happens is that fresh water does not
enter the water table when it rains. It runs off into our rivers.
According to the water dynamic discussed above it also picks up salt
and pollution. Gradually during dry periods the fresh water lens on
top of our aquifers is used up and the saltier water underneath
remains.
 Reused irrigation water brings with it the salt it has picked up along
the way.
Presentation downloadable from www.tececo.com
49
TecEco Eco-Cement Pervious Pavement
Permecocrete
Permecocrete
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?
TecEco have now perfected pervious pavements that can be made out of monograded recycled aggregates and other wastes and that sequester CO2.
Presentation downloadable from www.tececo.com
50
Cities as Profitable Carbon Sinks?
THERE is a way to make our
city streets as green as the
Amazon rainforest. Almost
every aspect of the built
environment, from bridges to
factories to tower blocks, and
from roads to sea walls, could
be turned into structures that
soak up carbon dioxide- the
main greenhouse gas behind
global warming. All we need to
do is change the way we make
cement. Pearce, F. (2002). "Green
Foundations." New Scientist 175(2351): 39-40.
Presentation downloadable from www.tececo.com
51
We Must Learn to Recycle Everything Including CO2
 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 calcium and magnesium
carbonate materials and other wastes in pervious
pavement mimics nature.
In eco-cement
blocks and mortars
the binder is
carbonate and the
aggregates are
preferably wastes
“Biomimicry Geomimicry”
We all use
carbon and
wastes to
make our
homes!
CO2
CO2
CO2
C
CO2
Pervious pavement
Presentation downloadable from www.tececo.com
Waste
52
Geomimicry
 There are 1.2-3 grams of
magnesium and about .4 grams of
calcium in every litre of seawater.
 Carbonate sediments such as
these cliffs represent billions
of years of sequestration
and cover 7% of the crust.
 There is enough calcium and
magnesium in seawater with
replenishment to last billions of
years at current needs for
sequestration.
 To survive we must build our
homes like these seashells using
CO2 and alkali metal cations. This
is geomimicry
Presentation downloadable from www.tececo.com
53
Geomimicry for Planetary Engineers?
 Large tonnages of carbon were put away during
earth’s geological history as limestone, dolomite,
magnesite, coal and oil by the activity of plants
and animals.
– Shellfish built shells from it and
– Trees turned it into wood.
 These same plants and animals wasted nothing
– The waste from one was the food or home for
another.
 Because of the colossal size of the flows involved
the answer to the problems of greenhouse gas
and waste is to use them both in building
materials.
Materials are very important
Presentation downloadable from www.tececo.com
54
Geomimicry for Planetary Engineers?
 Such a paradigm shift in resource usage will not occur
because it is the right thing to do.
– It can only happen economically.
 We must put an economic value on carbon to solve
global warming by
– Inventing new technical paradigms such as offered by the
Global Sustainability Alliance in Gaia Engineering.
– Evolving culturally to effectively use these technical
paradigms
– By using carbon dioxide and other wastes as a building
materials we could economically reduce their concentration in
the global commons.
Materials are very important
Presentation downloadable from www.tececo.com
55
Economically Driven Sustainability
New, more profitable
technical paradigms are
required that result in
more sustainable and
usually more efficient
moleconomic flows that
mimic natural flows or
better, reverse our
damaging flows.
$ - ECONOMICS - $
Change is only possible economically. It will not
happen because it is necessary or right.
Presentation downloadable from www.tececo.com
56
Changing the Technology Paradigm
It is not so much a matter of “dematerialisation” as a
question of changing the underlying moleconomic
flows. We need materials that require less energy to
make them, do not pollute the environment with CO2
and other releases, last much longer and that contribute
properties that reduce lifetime energies. The key is to
change the technology paradigms
“By enabling us to make productive use of particular
raw materials, technology determines what
constitutes a physical resource1”
1.Pilzer, Paul Zane, Unlimited Wealth, The Theory and Practice of Economic Alchemy, Crown
Publishers Inc. New York.1990
Presentation downloadable from www.tececo.com
57
Cultural Change







Al Gore (SOS)
CSIRO reports
STERN Report
Lots of Talkfest
IPCC Report
Branson Prize
Live Earth (07/07/07)
The media have a growing role
Presentation downloadable from www.tececo.com
58
Sustainability is Where Culture and Technology Meet
Increase in demand/price ratio for greater
sustainability due to cultural change.
$
ECONOMICS
We must rapidly
move both the
supply and demand
curves for
sustainability
Equilibrium
Shift
Supply
Greater Value/for impact
(Sustainability) and
economic growth
Increase in supply/price ratio for
more sustainable products due to
technical innovation.
Demand
#
A measure of the degree of sustainability of an industrial ecology is where the demand for
more sustainable technologies is met by their supply.
Presentation downloadable from www.tececo.com
59
Making Carbonate Building Materials to
Solve the Global Warming Problem
 How much magnesium carbonate would have to be
deposited to solve the problem of global warming?
– 12 billion tonnes CO2 ~= 22.99 billion tonnes magnesite
– The density of magnesite is 3 gm/cm3 or 3 tonne/metre3
 Thus 22.9/3 billion cubic metres ~= 7.63 cubic kilometres
of magnesite are required to be deposited each year.
 Compared to the over seven cubic kilometres of
concrete we make every year, the problem of global
warming looks surmountable.
 If magnesite was our building material of choice and we
could make it without releases as is the case with Gaia
Engineering, we have the problem as good as solved!
We must build with carbonate and waste
Gaia Engineering offers technical paradigms
allowing us to do so economically
Presentation downloadable from www.tececo.com
60
Huge Potential for Sequestration and Waste
Utilisation in the Built Environment
 Reducing the impact of the take and waste phases of the
techno-process by.
– including carbon in materials
they are potentially carbon sinks. Many wastes including CO2
can contribute to physical
– including wastes for
properties reducing lifetime
physical properties as
well as chemical composition
energies
they become resources.
– re engineering materials to
reduce the lifetime energy
CO2
of buildings
 A durable low pH high bonding
CO2
binder system is required
for effective waste utilisation
such as TecEco Tec and
Eco-Cements
CO
2
C
CO2
Waste
Pervious pavement
Presentation downloadable from www.tececo.com
61
Gaia Engineering Flowchart
CaO
Industrial CO2
TecEco
Tec-Kiln
Portland Cement
Manufacture
MgO
Clays
Fresh Water
Brine
or Sea
water
Extraction
Waste
Acid or
Bittern
s
Extraction
inputs and
outputs
depending
on method
chosen
MgCO3
and
CaCO3
“Stone”
TecEco
Cement
Manufacture
EcoCements
Valuable
Commodity
Salts or
hydrochloric
acid.
Building waste
TecCements
Building
components &
aggregates
Other waste
Built Environment
The Gaia Engineering Tececology
Industrial Ecologies are
generally thought of as
closed loop systems with
minimal or low impacts
outside the ecology
The Gaia Engineering
tececology could be
thought of as an open
technical ecology designed
to reverse major damaging
moleconomic and other
system flows outside the
tececology
The Gaia Engineering tececology is not closed and is designed
to reverse damaging moleconomic flows outside the ecology LIKE A GIANT ECOLOGICAL PUMP
Presentation downloadable from www.tececo.com
63
The Gaia Engineering Process
Inputs:
Atmospheric or industrial CO2,
brines, waste acid or bitterns, other wastes
Outputs:
Gaia Engineering delivers profitable
outcomes whilst reversing underlying
undesirable moleconomic flows from other
less sustainable techno-processes outside
the tececology.
Carbonate building materials, potable water,
valuable commodity salts.
Carbonate building components
CO2
Solar or solar
derived energy
CO2
CO2
MgO
Eco-Cement
TecEco
MgCO2
Cycle
TecEco
Kiln
MgCO3
Extraction
Process
1.29 gm/l Mg
.412 gm/l Ca
Coal
Carbon or carbon compounds
Magnesium compounds
CO2
Fossil fuels
Oil
TecEco Cements
SUSTAINABILITY
PORTLAND
POZZOLAN
Hydration of the
various components
of Portland cement
for strength.
DURABILITY
Reaction of alkali with
pozzolans (e.g. lime with fly
ash.) for sustainability,
durability and strength.
TECECO CEMENTS
STRENGTH
MAGNESIA
Hydration of magnesia => brucite fo strength, workability,
dimensional stability and durability. In Eco-cements
carbonation of brucite => nesquehonite, lansfordite and an
amorphous phase for sustainability.
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.
Presentation downloadable from www.tececo.com
65
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 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 (15-95% MgO, 85-5% OPC)
– contain more reactive magnesia than in tec-cements. Brucite in permeable
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 permeable
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.
Presentation downloadable from www.tececo.com
66
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
Presentation downloadable from www.tececo.com
67
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
Presentation downloadable from www.tececo.com
68
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 permeable substrates which are affective binders.
Reactive MgO is a new tool to be understood
with profound affects on most properties
Presentation downloadable from www.tececo.com
69
Why do Eco-Cements use Magnesium Compounds?
 At 2.09% of the crust magnesium is the 8th most abundant
element.
 Magnesium oxide is easy to make using non fossil fuel
energy and efficiently absorbs CO2
 Because magnesium has a low molecular weight,
proportionally a much greater amount of CO2 is released or
captured.
CO 2
44

 52%
MgCO3 84
CO 2
44

 43 %
CaCO 3 101
 A high proportion of water in the binder means that a little
binder goes a long way
Presentation downloadable from www.tececo.com
70
Strength with Blend & Porosity
150
Tec-cement concretes
Eco-cement concretes
100
50
High OPC
Enviro-cement
concretes
STRENGTH ON
ARBITARY SCALE 1-100
100-150
50-100
0-50
Presentation downloadable from www.tececo.com
0 High Porosity
High Magnesia
71
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.
– homogenous.
– no bleed water.
TecEco Technology - Converting Waste to Resource
Presentation downloadable from www.tececo.com
72
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.
Presentation downloadable from www.tececo.com
73
Eco-Cements
 Have high proportions of reactive magnesium oxide
 Carbonate like lime
 Generally used in a 1:5-1:12 paste basis because much more
carbonate “binder” is produced than with lime
MgO + H2O <=> Mg(OH)2
Mostly CO2
and water
Mg(OH)2 + CO2 + H2O <=> MgCO3.3H2O
58.31 + 44.01 <=> 138.32 molar mass (at least!)
24.29 + gas <=> 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
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”.
Presentation downloadable from www.tececo.com
74
Carbonation is Proportional to Porosity
Carbonation
Rate
Macro Porosity
Presentation downloadable from www.tececo.com
75
Carbonation is Proportional to Time
100 %
%
Carbonation
180 days Time
Presentation downloadable from www.tececo.com
76
CO2 Abatement in Eco-Cements
For 85 wt%
Aggregates
15 wt%
Cement
Eco-cements in
permeable
products absorb
carbon dioxide
from the
atmosphere.
Brucite carbonates
forming lansfordite,
nesquehonite and
an amorphous
phase, completing
the thermodynamic
cycle.
Portland
Cements
15 mass%
Portland
cement, 85
mass%
aggregate
Emissions
.32 tonnes to
the tonne.
After
carbonation.
Approximately
.299 tonne to
the tonne.
No
Capture
11.25% mass%
reactive
magnesia, 3.75
mass% Portland
cement, 85
mass%
aggregate.
Emissions
.37 tonnes to
the tonne. After
carbonation.
approximately
.241 tonne to
the tonne.
Capture
CO2
11.25% mass%
reactive
magnesia, 3.75
mass% Portland
cement, 85
mass%
aggregate.
Emissions
.25 tonnes to the
tonne. After
carbonation.
approximately
.140 tonne to
the tonne.
Capture
CO2. Fly and
Bottom Ash
11.25% mass%
reactive magnesia,
3.75 mass%
Portland cement,
85 mass%
aggregate.
Emissions
.126 tonnes to the
tonne. After
carbonation.
Approximately .113
tonne to the tonne.
Greater Sustainability
.299 > .241 >.140 >.113
Bricks, blocks, pavers, mortars and pavement made using eco-cement, fly
and bottom ash (with capture of CO2 during manufacture of reactive
magnesia) have 2.65 times less emissions than if they were made with
Portland cement.
Presentation downloadable from www.tececo.com
77
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
From air and water
is for example volume 811%.
Mg(OH)2 + CO2  MgCO3.5H2O
Presentation downloadable from www.tececo.com
78
Eco-Cement Strength Gain Curve
HYPOTHETICAL STRENGTH
GAIN CURVE OVER TIME
(Pozzolans added)
MPa
?
OPC Concrete
?
Eco – Cement Concrete with
50% reactive magnesia
?
?
3
Plastic
Stage
7
14
28
Log Days
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.
Presentation downloadable from www.tececo.com
79
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.
Presentation downloadable from www.tececo.com
80
Eco-Cement Reactions
In Eco - Cements
Magnesia
Amorphous Lansfordite
Brucite
Nesquehonite
MgO + nH2O  Mg(OH)2.nH2O + CO2  MgCO3.nH2O + MgCO3.5H2O + MgCO3.3H2O
Form: Massive-Sometimes Fibrous Often Fibrous Acicular - Needle-like
crystals
Hardness:
2.5 - 3.0
2.5
Solubility (mol.L-1): .00015
.01
.013 (but less in acids)
Compare to the Carbonation of Portlandite
Portlandite
Calcite
Aragonite
Ca(OH)2 + CO2  CaCO3
Form: Massive
Massive or crystalline
Hardness:
Solubility (mol.L-1):
More acicular
2.5
.024
3.5
.00014
Presentation downloadable from www.tececo.com
81
Eco-Cement Micro-Structural Strength
Elongated growths of
lansfordite and
nesquehonite near the
surface, growing inwards
over time and providing
microstructural strength.
Flyash grains (red)
reacting with lime
producing more CSH and
if alkaline enough
conditions bonding
through surface
hydrolysis. Also acting as
micro aggregates.
Portland clinker minerals
(black). Hydration
providing Imperfect
structural framework.
Micro spaces filled with
hydrating magnesia
(→brucite) – acting as a
“waterproof glue”
Mysterious amorphous
phase?
Presentation downloadable from www.tececo.com
82
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 permeable 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
Presentation downloadable from www.tececo.com
83
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 permeable
– requiring a coarse fraction to cause physical air voids and some vapour
permeability.
 Coarse fractions are required in the aggregates used!
Presentation downloadable from www.tececo.com
84
CO2 Abatement in Eco-Cements
For 85 wt%
Aggregates
15 wt%
Cement
Eco-cements in
permeable
products absorb
carbon dioxide
from the
atmosphere.
Brucite carbonates
forming lansfordite,
nesquehonite and
an amorphous
phase, completing
the thermodynamic
cycle.
Portland
Cements
15 mass%
Portland
cement, 85
mass%
aggregate
Emissions
.32 tonnes to
the tonne.
After
carbonation.
Approximately
.299 tonne to
the tonne.
No
Capture
11.25% mass%
reactive
magnesia, 3.75
mass% Portland
cement, 85
mass%
aggregate.
Emissions
.37 tonnes to
the tonne. After
carbonation.
approximately
.241 tonne to
the tonne.
Capture
CO2
11.25% mass%
reactive
magnesia, 3.75
mass% Portland
cement, 85
mass%
aggregate.
Emissions
.25 tonnes to the
tonne. After
carbonation.
approximately
.140 tonne to
the tonne.
Capture
CO2. Fly and
Bottom Ash
11.25% mass%
reactive magnesia,
3.75 mass%
Portland cement,
85 mass%
aggregate.
Emissions
.126 tonnes to the
tonne. After
carbonation.
Approximately .113
tonne to the tonne.
Greater Sustainability
.299 > .241 >.140 >.113
Bricks, blocks, pavers, mortars and pavement made using eco-cement, fly
and bottom ash (with capture of CO2 during manufacture of reactive
magnesia) have 2.65 times less emissions than if they were made with
Portland cement.
Presentation downloadable from www.tececo.com
85
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
Presentation downloadable from www.tececo.com
86
Net Emissions/Sequestration Compared
(Gaia Engineering Assumed)
Presentation downloadable from www.tececo.com
87
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.net/rosendale_natural_cement_.html
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88
A Post – Carbon Age
We all use carbon and wastes!
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89
Eco-Cement compared to Carbonating Lime Mortar.
 The underlying chemistry is very similar however eco-cements
are potentially superior to lime mortars because:
– The calcination phase of the magnesium thermodynamic cycle takes
place at a much lower temperature
– Magnesium minerals are generally more fibrous and acicular than
calcium minerals and hence a lot stronger.
– Water forms part of the binder minerals that forming making the cement
component go further.
– Magnesium hydroxide in particular and to some extent the carbonates
are less reactive and mobile and thus much more durable.
– A less reactive environment with a lower long term pH. (around 10.5
instead of 12.35)
 Because magnesium has a low molecular weight,
proportionally a much greater amount of CO2 is captured.
 Carbonation in the built environment would result in significant
sequestration because of the shear volumes involved.
 Carbonation adds considerable strength and some steel
reinforced structural concrete could be replaced with fibre
reinforced permeable carbonated concrete.
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90
A More Sustainable Built Environment
CO2
CO2 + H2O =>
Hydrocarbons
compounds using
bacteria
CO2
CO2
GREENSOLS
MAGNESIUM
CARBONATE
“There is a way to
make our city streets
as green as the
Amazon rainforest”.
Fred Pearce, New
Scientist Magazine
TECECO
KILN
MgO
ECO-CEMENT
CONCRETES
RECYCLED
BUILDING
MATERIALS
OTHER
WASTES
PERMANENT
SEQUESTRATION &
WASTE UTILISATION
(Man made carbonate
rock incorporating
wastes as a building
material)
Pareto’s principle 80% of the build
environment in non
structural and could
be carbonate from
Greensols held
together by EcoCements
SUSTAINABLE CITIES
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91
Conclusion
 Pervious pavements made with TecEco Eco-Cements
would utilise a considerable proportion of wastes
such as fly ash and as they would carbonate, provide
substantial abatement. Water entering aquifers,
streams and rivers would be of higher quality and
carry less macro pollutants.
 Cities with pervious pavements would be safer for
traffic, be cleaner and have less pollution
 Fresh water replenishment of aquifers would reduce
salinity and reverse falling water tables.
 Pervious pavements could provide a means for water
capture with in situ cleansing thereby solving the
water crisis in our cities
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92