Post on 19-Jan-2016
description
1Presentation downloadable from www.tececo.com
Pervious PavementPervious Pavement
“We can't solve problems by using the same kind of thinking we used when we created them." Pervious pavements are a different way of thinking about roads. Albert Einstein
John Harrison, B.Sc. B.Ec. FCPA
2Presentation downloadable from www.tececo.com
What Is Pervious Pavement?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. Pervious materials such as ancient lime mortars and pervious pavements are made using relatively mono graded materials. In the case of pervious pavement this translates as a lack of "fine" materials. No fines concrete or under asphalted gravel are names for common materials used.
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. They are safer to drive on as they do not develop "puddles", have a good surface to grip and importantly, in Australia, some parts of the US and many other places in the world subdivisions made with pervious pavement that also have street trees can be several degrees cooler than surrounding suburbs without.
3Presentation downloadable from www.tececo.com
The Water CycleThe Water CycleThe 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)
4Presentation downloadable from www.tececo.com
Australia Before SettlementAustralia Before Settlement
In years gone by grasslan
d and forest
covered the land
5Presentation downloadable from www.tececo.com
Australia NowAustralia Now
Paper Mill - Soda liquor + Cl
Forestry - Cover removal
Farming - Pesticide, N P K
Cows - methane
Vehicles - carbon dioxide
Immediate and polluted water run-off.Air pollution.Carbon dioxide and other gases.Putrescible wastes. Huge linkages.
Our impacts
on the environme
nt are many and damaging
6Presentation downloadable from www.tececo.com
Our LegacyOur 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 pervious Tec-Pavement solution.
7Presentation downloadable from www.tececo.com
Australia with a Little Lateral Thinking & EffortAustralia with a Little Lateral Thinking & Effort
Less paper. Other Cl free processes - no salinity
Evolution away from using trees – paperless office
Organic farming Carbon returned to soils.
Cows – CSIO anti methane bred
Vehicles – more efficient and using fuel cells
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.
TecEco technology provides ways ofsequestering carbon dioxide and utilising wastes to create our techno - world
It is essential we learn
to live with
nature and
change our ways
8Presentation downloadable from www.tececo.com
One Planet, Many People, Many Interconnected ProblemsOne 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.
9Presentation downloadable from www.tececo.com
Global Fresh WaterGlobal Fresh WaterA 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
10Presentation downloadable from www.tececo.com
Australia’s Water ProblemsAustralia’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.
11Presentation downloadable from www.tececo.com
Stormwater = Rainwater + PollutionStormwater = 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?
12Presentation downloadable from www.tececo.com
Point and Non-Point Source PollutionPoint 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.
13Presentation downloadable from www.tececo.com
Stormwater = Rainwater + PollutionStormwater = Rainwater + Pollution
Source: thesource.melbournewater.com.au/.../river.htm
14Presentation downloadable from www.tececo.com
Sources and Types of PollutionSources and Types of Pollution
Land uses Types of pollutionRural/agricultural &market
gardensSilt, pesticides, fertilisers, livestock faeces.
Residential properties & gardensDetergent, pesticides, fertiliser, dog faeces, leaf litter.
Industrial areas Industrial runoff & acidity
Roads & carparksOil, petrol, heavy metals, leaf litter
Shopping centresLitter, 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 reservesLitter, dog and cat faeces, grass cuttings, leaves
Adapted from: www.cwmb.sa.gov.au/kwc/section1/1-24.htm
15Presentation downloadable from www.tececo.com
Types of Pollution (1)Types of Pollution (1)
Modified from:EPA stormwater code of practice from www.cwmb.sa.gov.au/kwc/section1/1-24.htm
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
16Presentation downloadable from www.tececo.com
Types of Pollution (2)Types of Pollution (2)
Source:EPA stormwater code of practice from www.cwmb.sa.gov.au/kwc/section1/1-24.htm
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
17Presentation downloadable from www.tececo.com
Roads Interrupt Natural DrainageRoads 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
Keith Stichler, CDR
Various sources!
18Presentation downloadable from www.tececo.com
Roads are the Drainage NetworkRoads are the Drainage Network
And represent a huge wasted catchment
19Presentation downloadable from www.tececo.com
Impervious Watersheds Kill Rivers and Speed up the Water Cycle
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.
20Presentation downloadable from www.tececo.com
Purifying WaterPurifying 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.
21Presentation downloadable from www.tececo.com
Pervious Pavements Act Like a Giant Biofilter
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 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.
22Presentation downloadable from www.tececo.com
Speed, Volume Sediment Load and PollutionSpeed, Volume Sediment Load and Pollution
Low speed, low volume low distance covered = low pollution and salts
Higher speed, higher volume, more energy, greater distance covered = more pollution and salts
Rainwater does good all the way to the sea. Polluted and salty water do no good at all
23Presentation downloadable from www.tececo.com
Traps Do Not Stop Micro and Molecular PollutionTraps Do Not Stop Micro and Molecular Pollution
www.azstorm.org/public_edu.php
Source www.dpiw.tas.gov.au/.../RPIO-4YJ3KA?open
Traps are useless for stopping most pollutants other than those that are unsightly
24Presentation downloadable from www.tececo.com
The Functions of RoadsThe 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
25Presentation downloadable from www.tececo.com
Current Road Designs are Not SustainableCurrent Road Designs are Not SustainableTraffic Engineers
Drainage and Traffic Engineers
Sewerage Engineers
Electrical Engineers
Telecommunication Engineers
Gas Engineers
Hydraulic Engineers
Management
Ratepayers
The various groups with an interest in roads do not work together holistically
Geo Technical Engineers
How often do you see the same section of road dug up repeatedly in quick succession?
Environmental Scientists
26Presentation downloadable from www.tececo.com
Changing the Road ParadigmChanging 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
27Presentation downloadable from www.tececo.com
Building a New ModelBuilding 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 for these purposes.
28Presentation downloadable from www.tececo.com
Heads First for ActionHeads 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
29Presentation downloadable from www.tececo.com
Our Guide - Biomimicry - GeomimicryOur 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
30Presentation downloadable from www.tececo.com
Pervious Concrete Pavement - Addressing the IssuesPervious Concrete Pavement - Addressing the Issues
Image source: http://www.perviouspavement.org/
Pervious pavement is a unique and effective means of addressing environmental issues
31Presentation downloadable from www.tececo.com
TecEco Permecocrete - Thinking About Water and Roads
TecEco Permecocrete - Thinking About Water and Roads
Optional impervious layer, underground drainage and storage. Dual water supply or parks etc. only.
Optional groundwater recharge
The substrate must be properly designed
Moisture retention
Cleansing microbial activity and oxygenation
Cooling Evaporation
Pavements are not just for vehicles. They must do much more
CO2 CO2CO2 CO2 CO2
CO2
Sequestration
32Presentation downloadable from www.tececo.com
Holistic Roads for the FutureHolistic Roads for the Future
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.
Conventional bitumen or concrete footpath pavement
Impermeable layer (concrete or plastic liner) angling for main flow towards collection drains
Pervious Eco-Cement concrete pavement (Permecocrete) surface using recycled aggregates
Pervious gravel under for collection, cleansing and storage of water
Collection drains to transport drain or pipe in service conduit at intervals
Services to either side of the road. All in same trench of conduit
Possible leakage to street trees and underground aquifers
Its time for a road re think!
Service conduit down middle of road
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.
33Presentation downloadable from www.tececo.com
Placing Pervious PavementPlacing Pervious Pavement
Source: www.percocrete.com
34Presentation downloadable from www.tececo.com
Finishing Pervious PavementFinishing Pervious Pavement
Source: www.percocrete.com
35Presentation downloadable from www.tececo.com
Laying Pervious PavementLaying Pervious Pavement
Source: www.percocrete.com
36Presentation downloadable from www.tececo.com
Cross Section Pervious PavementCross Section Pervious Pavement
Source: www.percocrete.com
37Presentation downloadable from www.tececo.com
TecEco PermecocreteTecEco 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 accoustic properties– Reduces building maintenance– Cooler Suberbs– Reduced drainage infrastructure costs
• Reduces the need for culverts, pies drains, retention ponds, swales, and other stormwater management devices.
– Less watering of street trees
38Presentation downloadable from www.tececo.com
Environmental AdvantagesEnvironmental 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.
39Presentation downloadable from www.tececo.com
Non Environmental AdvantagesNon 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
40Presentation downloadable from www.tececo.com
Hot City Syndrome and Pervious PavementHot 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?
41Presentation downloadable from www.tececo.com
Solving the Water ProblemSolving the Water ProblemCollecting Rain Water Using Pervious PavementCollecting 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.
42Presentation downloadable from www.tececo.com
TecEco Eco-Cement Pervious PavementTecEco Eco-Cement Pervious Pavement
Allow many mega litres of good fresh water to become contaminated by the pollutants on our streets and pollute coastal waterways
Capture and cleanse the water for our use?
Or
Permecocrete
TecEco have now perfected pervious pavements that can be made out of mono-graded recycled aggregates and other wastes and that sequester CO2.
Permecocrete
43Presentation downloadable from www.tececo.com
TecEco Eco-Cement Permecocrete - Mimicking Nature
TecEco 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 storage e.g. under drive
Permecocrete pervious pavement
Water featurekeeps water
clean
Pump
All rainwater redirected to pavement filter.
44Presentation downloadable from www.tececo.com
SalinitySalinity 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
45Presentation downloadable from www.tececo.com
Irrigation SalinityIrrigation Salinity According to the Australian National Action plan website at
http://www.napswq.gov.au/publications/salinity.html#how salinity occurs when irrigation 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.gov.au/publications/salinity.html#how
46Presentation downloadable from www.tececo.com
Dryland Salinity – Caused by ClearingDryland 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.
TecEco consider this view substantially incorrect. See our web site at http://www.tececo.com/sustainability.salinity_pollution.php and what follows
Figures from the Australian National Action plan website at http://www.napswq.gov.au/publications/salinity.html#how
47Presentation downloadable from www.tececo.com
Dryland Salinity – Caused by EvaporationDryland 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
48Presentation downloadable from www.tececo.com
Salinity, Agricultural Practices and Pervious PavementSalinity, Agricultural Practices and Pervious Pavement
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.
Deep rooted salt tolerent species (The PundaZoie company)
Native tree belts
Salinity in untreated areas
Deep drains
TecEco permecocrete roads
Salinity in untreated areas
Salty water
Fresh water
Contoured swales
49Presentation downloadable from www.tececo.com
How Our Theories Differ on SalinityHow 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.
For more information please see our web site at http://www.tececo.com/sustainability.salinity_pollution.php
50Presentation downloadable from www.tececo.com
The Clogging Myth - Cleaning Pervious PavementThe Clogging Myth - Cleaning Pervious Pavement
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.
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 waterwaysFrimokar Australia
high pressure jet and suction cleaning in action
51Presentation downloadable from www.tececo.com
We Must Learn to Recycle Everything Including CO2We 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
C
CO2
Waste
CO2
CO2
Pervious pavement
52Presentation downloadable from www.tececo.com
GeomimicryGeomimicry 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.
53Presentation downloadable from www.tececo.com
Geomimicry for Planetary Engineers?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
54Presentation downloadable from www.tececo.com
Geomimicry for Planetary Engineers?Geomimicry for Planetary Engineers? The answer to the problems of greenhouse gas
and waste is to use them both in building materials.– 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
55Presentation downloadable from www.tececo.com
Economically Driven SustainabilityEconomically 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.
56Presentation downloadable from www.tececo.com
Changing the Technology ParadigmChanging the Technology Paradigm
“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
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
57Presentation downloadable from www.tececo.com
Cultural ChangeCultural 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
58Presentation downloadable from www.tececo.com
Sustainability is Where Culture and Technology MeetSustainability is Where Culture and Technology Meet
Increase in demand/price ratio for greater sustainability due to cultural change.
#
$
Demand
Supply
Increase in supply/price ratio for more sustainable products due to technical innovation.
Equilibrium
ShiftECONOMICSGreater Value/for impact (Sustainability) and economic growth
A measure of the degree of sustainability of an industrial ecology is where the demand for more sustainable technologies is met by their supply.
We must rapidly move both the supply and demand curves for sustainability
59Presentation downloadable from www.tececo.com
Making Pervious PavementMaking 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 pervious 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.
Eco-Cement Permecocrete Pervious PavementSet by absorbing CO2Can use recycled materials as long as they are hard and mono-graded
AsphaltCarcenogenic to workers using it.Becoming more expensive as petroleum supplies dwindle.
60Presentation downloadable from www.tececo.com
Making Carbonate Building Materials to Solve the Global Warming Problem
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
61Presentation downloadable from www.tececo.com
The Gaia Engineering ProcessThe Gaia Engineering Process
Greensols Process
Fossil fuels
Solar or solar derived energy
Oil
MgO
CO2
Coal
CO2
MgCO3
CO2
CO2
Inputs:
Atmospheric or smokestack CO2, brines,waste acid, other wastes
Outputs:
Potable water, gypsum, sodium bicarbonate, salts, building materials, bottled concentrated CO2 (for algal fuel production and other uses).
Carbon or carbon compoundsMagnesium compounds
1.29 gm/l Mg
TecEco MgCO2
Cycle
TecEcoKiln
Carbonate building components
Eco-Cement
62Presentation downloadable from www.tececo.com
TecEco CementsTecEco CementsSUSTAINABILITY
DURABILITY STRENGTHTECECO CEMENTS
Hydration of the various components of Portland cement for strength.
Reaction of alkali with pozzolans (e.g. lime with fly ash.) for sustainability, durability and strength.
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.
PORTLAND
POZZOLAN
MAGNESIA
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.
63Presentation downloadable from www.tececo.com
TecEco FormulationsTecEco 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 pervious 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 pervious 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.
64Presentation downloadable from www.tececo.com
Tec & Eco-Cement TheoryTec & 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
65Presentation downloadable from www.tececo.com
Tec & Eco-Cement TheoryTec & 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
66Presentation downloadable from www.tececo.com
Why Add Reactive Magnesia?Why Add Reactive Magnesia?
To maintain the long term stability of CSH.– Maintains alkalinity preventing the reduction in Ca/Si ratio.
To remove water.– Reactive magnesia consumes water as it hydrates to possibly hydrated
forms of Brucite. To raise the early Ph.
– Increasing non hydraulic strength giving reactions To reduce shrinkage.
– The consequences of putting brucite through the matrix of a concrete in the first place need to be considered.
To make concretes more durable Because significant quantities of carbonates are
produced in permeable substrates which are affective binders.
Reactive MgO is a new tool to be understood with profound affects on most properties
67Presentation downloadable from www.tececo.com
Why do Eco-Cements use Magnesium Compounds?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.
A high proportion of water in the binder means that a little binder goes a long way
%5284
44
3
2
MgCO
CO
%43101
44
3
2
CaCO
CO
68Presentation downloadable from www.tececo.com
Strength with Blend & PorosityStrength with Blend & Porosity
0
50
100
150
100-150
50-100
0-50
High OPC High Magnesia
High Porosity
STRENGTH ON ARBITARY SCALE 1-100
Tec-cement concretes
Eco-cement concretes
Enviro-cement concretes
69Presentation downloadable from www.tececo.com
Solving Waste & Logistics ProblemsSolving 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
70Presentation downloadable from www.tececo.com
Eco-CementsEco-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.
71Presentation downloadable from www.tececo.com
Eco-CementsEco-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
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
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”.
72Presentation downloadable from www.tececo.com
Carbonation is Proportional to PorosityCarbonation is Proportional to Porosity
CarbonationRate
Macro Porosity
73Presentation downloadable from www.tececo.com
Carbonation is Proportional to TimeCarbonation is Proportional to Time
% Carbonation
Time
100 %
180 days
74Presentation downloadable from www.tececo.com
CO2 Abatement in Eco-CementsCO2 Abatement in Eco-Cements
Eco-cements in pervious products absorb carbon dioxide from the atmosphere. Brucite carbonates forming lansfordite, nesquehonite and an amorphous phase, completing the thermodynamic cycle.
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.
.299 > .241 >.140 >.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.
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
Greater Sustainability
75Presentation downloadable from www.tececo.com
Eco-Cement Strength DevelopmentEco-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%.
Mg(OH)2 + CO2 MgCO3.5H2O
From air and water
76Presentation downloadable from www.tececo.com
Eco-Cement Strength Gain CurveEco-Cement Strength Gain Curve
Eco – Cement Concrete with 50% reactive magnesia
OPC Concrete
HYPOTHETICAL STRENGTH GAIN CURVE OVER TIME (Pozzolans added)
MPa
Log Days Plastic Stage
?
?
?
?
7 14 28 3
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.
77Presentation downloadable from www.tececo.com
Chemistry of Eco-CementsChemistry 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.
78Presentation downloadable from www.tececo.com
Eco-Cement ReactionsEco-Cement Reactions
Hardness: 2.5 - 3.0 2.5
Form: Massive-Sometimes Fibrous Often Fibrous Acicular - Needle-like crystals
Solubility (mol.L-1): .00015 .01 .013 (but less in acids)
Magnesia Brucite Amorphous Lansfordite
MgO + nH2O Mg(OH)2.nH2O + CO2 MgCO3.nH2O + MgCO3.5H2O + MgCO3.3H2O
In Eco - Cements
Hardness: 2.5 3.5
Form: Massive Massive or crystalline More acicular
Solubility (mol.L-1): .024 .00014
Portlandite Calcite
Ca(OH)2 + CO2 CaCO3
Compare to the Carbonation of Portlandite
Aragonite
Nesquehonite
79Presentation downloadable from www.tececo.com
Eco-Cement Micro-Structural StrengthEco-Cement Micro-Structural Strength
Elongated growths of lansfordite and nesquehonite near the surface, growing inwards over time and providing microstructural strength.
Portland clinker minerals (black). Hydration providing Imperfect structural framework.
Micro spaces filled with hydrating magnesia (→brucite) – acting as a “waterproof glue”
Flyash grains (red) reacting with lime producing more CSH and if alkaline enough conditions bonding through surface hydrolysis. Also acting as micro aggregates.
Mysterious amorphous phase?
80Presentation downloadable from www.tececo.com
CarbonationCarbonation
Eco-cement is based on blending reactive magnesium oxide with other hydraulic cements and then allowing the Brucite and Portlandite components to carbonate in pervious 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
81Presentation downloadable from www.tececo.com
Aggregate Requirements for CarbonationAggregate 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 pervious– requiring a coarse fraction to cause physical air voids and some vapour
permeability. Coarse fractions are required in the aggregates used!
82Presentation downloadable from www.tececo.com
CO2 Abatement in Eco-CementsCO2 Abatement in Eco-Cements
Eco-cements in pervious products absorb carbon dioxide from the atmosphere. Brucite carbonates forming lansfordite, nesquehonite and an amorphous phase, completing the thermodynamic cycle.
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.
.299 > .241 >.140 >.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.
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
Greater Sustainability
83Presentation downloadable from www.tececo.com
TecEco Cement LCATecEco 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
84Presentation downloadable from www.tececo.com
Net Emissions/Sequestration ComparedNet Emissions/Sequestration Compared
Net Emissions (Sequestration) per kg Cement
-0.80
-0.60
-0.40
-0.20
0.00
0.20
0.40
0.60
0.80
1.00
Por
tland
Cem
ent
Mag
nesi
a
Lim
e
Tec
-Cem
ent
Eco
-Cem
ent
Lim
e M
orta
r
Env
iro-C
emen
t
Net Emissions(Sequestration) per kgCement
(Gaia Engineering Assumed)
85Presentation downloadable from www.tececo.com
Rosendale Concretes – Proof of DurabilityRosendale 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
86Presentation downloadable from www.tececo.com
A Post – Carbon AgeA Post – Carbon Age
Prehistoric Classic Renaissance Industrial Revolution Contemporary Post Carbon Age
Recyclable Recyclable
CO2
Wattle & daub Stone Mud brick Etc.
Stone
Stone Brick
Concrete Concrete Steel Aluminium
Eco-cements
We all use carbon and wastes!
87Presentation downloadable from www.tececo.com
Eco-Cement compared to Carbonating Lime Mortar. 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 pervious carbonated concrete.
88Presentation downloadable from www.tececo.com
A More Sustainable Built EnvironmentA More Sustainable Built Environment
MAGNESIUM CARBONATE
ECO-CEMENTCONCRETES
SUSTAINABLE CITIES
CO2
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 Eco-Cements
CO2
MgOTECECO KILN
RECYCLED BUILDING MATERIALS
OTHERWASTES
“There is a way to make our city streets as green as the Amazon rainforest”. Fred Pearce, New Scientist Magazine
CO2 + H2O =>Hydrocarbons compounds using bacteria
GREENSOLS
CO2
89Presentation downloadable from www.tececo.com
ConclusionConclusion 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