Title: Pervious%20Pavement
1Pervious 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
2What 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.
3The 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.
SourceIllustration by John M. Evans USGS,
Colorado District (http//ga.water.usgs.gov/edu/wa
tercyclegraphichi.html)
4Australia Before Settlement
In years gone by grassland and forest covered the
land
5Our 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.
6Australia with a Little Lateral Thinking Effort
TecEco technology provides ways ofsequestering
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
Organic farming Carbon returned to soils.
Pervious pavements prevent immediate and polluted
run-off. Carbon dioxide and other gases absorbed
by TecEco Eco- Cements. Sewerage converted to
fertilizer and returned to soils. Buildings
generate own energy etc.
It is essential we learn to live with nature and
change our ways
7One 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.
8Global 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
9Australias 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.
10Stormwater 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?
11Point and Non-Point Source Pollution
- Point Source PollutionPoint 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 PollutionNon-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.
12Stormwater Rainwater Pollution
Source thesource.melbournewater.com.au/.../river.
htm
13Sources and Types of Pollution
Land uses Types of pollution
Rural/agricultural market gardens Silt, pesticides, fertilisers, livestock 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
14Types 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. MacroMicro 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
15Types 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
16Roads 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
17Roads are the Drainage Network
And represent a huge wasted catchment
18Impervious 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.
19Purifying 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.
20Pervious 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 air exchange capability to
maintain themselves and perform their cleaning
functions.
Source Wikipedia. Filtration system in a typical
aquarium (1) Intake. (2) Mechanical filtration.
(3) Chemical filtration. (4) Biological
filtration medium. (5) Outflow to tank.
21Speed, Volume Sediment Load and Pollution
Rainwater does good all the way to the sea.
Polluted and salty water do no good at all
Higher speed, higher volume, more energy, greater
distance covered more pollution and salts
Low speed, low volume low distance covered low
pollution and salts
The Water Dynamic
22Traps Do Not Stop Micro and Molecular Pollution
Source www.dpiw.tas.gov.au/.../RPIO-4YJ3KA?open
Traps are useless for stopping most pollutants
other than those that are unsightly
www.azstorm.org/public_edu.php
23The 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
24Current Road Designs are Not Sustainable
Traffic Engineers
Drainage and Traffic Engineers
Sewerage Engineers
Management
Hydraulic Engineers
Environmental Scientists
Gas Engineers
Ratepayers
Electrical Engineers
Telecommunication Engineers
Geo Technical Engineers
How often do you see the same section of road dug
up repeatedly in quick succession?
The various groups with an interest in roads do
not work together holistically
25Changing 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
26Building 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?
27Heads 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
28Our 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
29Pervious Concrete Pavement - Addressing the Issues
Pervious pavement is a unique and effective means
of addressing environmental issues
Image source http//www.perviouspavement.org/
30TecEco Permecocrete - Thinking About Water and
Roads
Pavements are not just for vehicles. They must do
much more
Cooling Evaporation
Sequestration
Moisture retention
Cleansing microbial activity and oxygenation
The substrate must be properly designed
Optional groundwater recharge
Optional impervious layer, underground drainage
and storage. Dual water supply or parks etc. only.
31Holistic 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 Eco-Cement concrete pavement
(Permecocrete) surface using recycled aggregates
Pervious gravel under for collection, cleansing
and storage of water
Services to either side of the road. All in same
trench of conduit
Service conduit down middle of road
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.
Collection drains to transport drain or pipe in
service conduit at intervals
Impermeable layer (concrete or plastic liner)
angling for main flow towards collection drains
Possible leakage to street trees and underground
aquifers
Its time for a road re think!
32TecEco Eco-Cement Permecocrete - Mimicking Nature
- 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.
Water featurekeeps water clean
All rainwater redirected to pavement filter.
Permecocrete pervious pavement
Pump
Water storage e.g. under drive
33Placing Pervious Pavement
Source www.percocrete.com
34Finishing Pervious Pavement
Source www.percocrete.com
35Laying Pervious Pavement
Source www.percocrete.com
36Cross Section Pervious Pavement
Source www.percocrete.com
37TecEco 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
38Environmental 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 bio-filters at the same time. - Replenish aquifers or provide water
- Reducing salinity by replenishment with fresh
water. - Permecocretes are also carbon sinks.
39Non 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
40Hot 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!
Its 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?
41Solving the Water Problem
Collecting Rain Water Using Pervious 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.
42The 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.
43Making Pervious Pavement
- Ideally a pervious pavement should be made with
mono-graded 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.
44Salinity
- 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.ht
mlhow) and CSIRO web sites there are two main
causes of salinity - irrigation salinity
- dryland salinity
- Caused by clearing
- Caused by evaporation
45Irrigation Salinity
- According to the Australian National Action plan
website at http//www.napswq.gov.au/publications/s
alinity.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-salin
ity-aridity has destroyed many civilisations
will ours be next?
Figure from the Australian National Action plan
website at http//www.napswq.gov.au/publications/s
alinity.htmlhow
46Dryland Salinity Caused by Clearing
- According to the Australian National Action plan
website at http//www.napswq.gov.au/publications/s
alinity.htmlhow 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/s
alinity.htmlhow
47Dryland 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.htm
l
48Salinity, Agricultural Practices and Pervious
Pavement
Native tree belts
Deep rooted salt tolerent species (The PundaZoie
company)
Salinity in untreated areas
TecEco permecocrete roads
Salinity in untreated areas
Contoured swales
Deep drains
Fresh water
Salty 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.
49How 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.
50TecEco Eco-Cement Pervious Pavement
Permecocrete
Allow many mega litres of good fresh water to
become contaminated by the pollutants on our
streets and pollute coastal waterways
Permecocrete
Or
Capture and cleanse the water for our use?
TecEco have now perfected pervious pavements that
can be made out of mono-graded recycled
aggregates and other wastes and that sequester
CO2.
51Cities 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.
52We 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.
We all use carbon and wastes to make our homes!
In eco-cement blocks and mortars the binder is
carbonate and the aggregates are preferably
wastes Biomimicry - Geomimicry
53Geomimicry
- There are 1.2-3 grams of magnesium and about .4
grams of calcium in every litre of seawater. - 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
- Carbonate sediments such as these cliffs
represent billionsof years of sequestrationand
cover 7 of the crust.
54Geomimicry for Planetary Engineers?
- Large tonnages of carbon were put away during
earths 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
55Geomimicry 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
56Economically 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.
57Changing 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 - Pilzer, Paul Zane, Unlimited Wealth, The Theory
and Practice of Economic Alchemy, Crown
Publishers Inc. New York.1990
58Cultural 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
59Sustainability is Where Culture and Technology
Meet
Increase in demand/price ratio for greater
sustainability due to cultural change.
Supply
Equilibrium Shift
Greater Value/for impact (Sustainability) and
economic growth
ECONOMICS
We must rapidly move both the supply and demand
curves for sustainability
Demand
Increase in supply/price ratio for more
sustainable products due to technical innovation.
A measure of the degree of sustainability of an
industrial ecology is where the demand for more
sustainable technologies is met by their supply.
60Making 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
61Huge 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 materialsthey are
potentially carbon sinks. - including wastes forphysical properties aswell
as chemical compositionthey become resources. - re engineering materials toreduce the lifetime
energyof buildings - A durable low pH high bondingbinder system is
requiredfor effective waste utilisationsuch as
TecEco Tec andEco-Cements
Many wastes including CO2 can contribute to
physical properties reducing lifetime energies
CO2
CO2
CO2
C
CO2
Waste
Pervious pavement
62Gaia Engineering Flowchart
Portland CementManufacture
CaO
TecEcoTec-Kiln
Industrial CO2
MgO
Clays
Fresh Water
TecEcoCementManufacture
MgCO3 and CaCO3Stone
Brine or Seawater
Extraction
Eco-Cements
WasteAcid or Bitterns
Tec-Cements
Valuable Commodity Salts or hydrochloric acid.
Buildingcomponents aggregates
Extraction inputs and outputs depending on method
chosen
Other waste
Built Environment
Building waste
63The Gaia Engineering Tececology
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
Industrial Ecologies are generally thought of as
closed loop systems with minimal or low impacts
outside the ecology
The Gaia Engineering tececology is not closed and
is designed to reverse damaging moleconomic flows
outside the ecology - LIKE A GIANT ECOLOGICAL PUMP
64The Gaia Engineering Process
Gaia Engineering delivers profitable outcomes
whilst reversing underlying undesirable
moleconomic flows from other less sustainable
techno-processes outside the tececology.
Inputs Atmospheric or industrial CO2,brines,
waste acid or bitterns, other wastes Outputs Carb
onate building materials, potable water, valuable
commodity salts.
Carbonate building components
Solar or solar derived energy
TecEcoKiln
TecEco MgCO2 Cycle
MgO
Eco-Cement
MgCO3
Extraction Process
1.29 gm/l Mg.412 gm/l Ca
Coal
Fossil fuels
Carbon or carbon compoundsMagnesium compounds
Oil
65TecEco Cements
TecEco concretes are a system of blending
reactive magnesia, Portland cement and usually a
pozzolan with other materials and are a key
factor for sustainability.
66TecEco 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 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.
67Tec 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
68Tec 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
69Why 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
70Why 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. - A high proportion of water in the binder means
that a little binder goes a long way
71Strength with Blend Porosity
Tec-cement concretes
Eco-cement concretes
High Porosity
Enviro-cement concretes
High OPC
High Magnesia
STRENGTH ON ARBITARY SCALE 1-100
72Solving 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
73Eco-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.
74Eco-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.
75Carbonation is Proportional to Porosity
CarbonationRate
Macro Porosity
76Carbonation is Proportional to Time
100
Carbonation
Time
180 days
77CO2 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 permeable 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.
78Eco-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.
79Eco-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.
80Chemistry 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.
81Eco-Cement Reactions
82Eco-Cement Micro-Structural Strength
83Carbonation
- 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
84Aggregate 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!
85CO2 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 permeable 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.
86TecEco 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
87Net Emissions/Sequestration Compared
(Gaia Engineering Assumed)
88Rosendale 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
89A Post Carbon Age
We all use carbon and wastes!
90Eco-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.
91A More Sustainable Built Environment
CO2 H2O gtHydrocarbons compounds using bacteria
CO2
OTHERWASTES
PERMANENT SEQUESTRATION WASTE UTILISATION (Man
made carbonate rock incorporating wastes as a
building material) Paretos principle -80 of the
build environment in non structural and could be
carbonate from Greensols held together by
Eco-Cements
GREENSOLS
ECO-CEMENTCONCRETES
MgO
TECECO KILN
MAGNESIUM CARBONATE
RECYCLED BUILDING MATERIALS
There is a way to make our city streets as green
as the Amazon rainforest. Fred Pearce, New
Scientist Magazine
SUSTAINABLE CITIES
92Conclusion
- 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