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Pervious Pavement “We can't solve problems by using the same kind of thinking we used when we created them." Albert Einstein. Pervious Pavements are a.

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Presentation on theme: "Pervious Pavement “We can't solve problems by using the same kind of thinking we used when we created them." Albert Einstein. Pervious Pavements are a."— Presentation transcript:

1 Pervious Pavement “We can't solve problems by using the same kind of thinking we used when we created them." Albert Einstein. Pervious Pavements are a different way of thinking about roads. John Harrison, B.Sc. B.Ec. FCPA

2 What Is Pervious Pavement?
Pervious pavement is a permeable pavement surface with a stone reservoir underneath. The reservoir temporarily stores surface runoff before infiltrating it into the subsoil or sub-surface drainage and in the process improves the water quality. Permeable materials such as ancient lime mortars and pervious pavements are made using relatively mono graded materials. Pervious pavements allow the earth to breathe, take in water and be healthy. The stone and soil under them acts as a reservoir and cleans the water just like the filter on a fish tank. Pervious pavements are safer to drive on as they do not develop "puddles", have a good surface to grip Subdivisions made with pervious pavement that also have street trees can be several degrees cooler than surrounding suburbs without.

3 The Water Cycle The water or hydrological cycle is powered by the sun and water changes state and is stored as it moves through it. Human intervention is reducing the time it takes for water to return to the oceans resulting in less moisture on land, salinity and aridity. Source:Illustration by John M. Evans USGS, Colorado District (http://ga.water.usgs.gov/edu/watercyclegraphichi.html)

4 Australia Before Settlement
John Harrison Presentation AASMIC Conference Australia Before Settlement HUGE MATERIALS FLOWS IN THE BUILT ENVIRONMENT The built environment is our footprint, a major proportion of the techno-sphere and our lasting legacy on the planet. In this dominant proportion of all materials flows and unsustainable practices abound from the logging of old growth forests to the high volume of wastage at landfill. The dominant proportion of what we take, manipulate and make that we do not consume immediately goes into the materials with which we build the built environment or “techno-sphere”. Buildings and infrastructure probably account for around 70% of all materials flows (TecEco estimate). Buildings alone account for 40 percent of the materials and about a third of the energy consumed by the world economy. Construction activities contributed over 35% of total global CO2 emissions in 1999. According to the Green Building Council of Australia Building waste is 40% of all waste going to landfill in Australia. In years gone by grassland and forest covered the land

5 Our Legacy In years gone by forests and grassland covered most of our planet. When it rained much of the water naturally percolated though soils that performed vital functions of slowing down the rate of transport to rivers and streams, purifying the water and replenishing natural aquifers. Our legacy has been to pave this natural bio filter, redirecting the water that fell as rain as quickly as possible to the sea. Given global water shortages, problems with salinity, pollution, volume and rate of flow of runoff we need to change our practices so as to mimic the way it was for so many millions of years before we started making so many changes. The key to survival in the future will be learning from nature and mimicking her subtle processes. Road are the arteries, veins and lymphatic system to cities. This presentation focuses on where we have gone wrong with roads and the radical TecEco Permecocrete solution.

6 Australia with a Little Lateral Thinking & Effort
John Harrison Presentation AASMIC Conference Australia with a Little Lateral Thinking & Effort TecEco technology provides ways of sequestering carbon dioxide and utilising wastes to create our techno - world Less paper. Other Cl free processes - no salinity Evolution away from using trees – paperless office Cows – CSIO anti methane bred 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. HUGE MATERIALS FLOWS IN THE BUILT ENVIRONMENT The built environment is our footprint, a major proportion of the techno-sphere and our lasting legacy on the planet. In this dominant proportion of all materials flows and unsustainable practices abound from the logging of old growth forests to the high volume of wastage at landfill. The dominant proportion of what we take, manipulate and make that we do not consume immediately goes into the materials with which we build the built environment or “techno-sphere”. Buildings and infrastructure probably account for around 70% of all materials flows (TecEco estimate). Buildings alone account for 40 percent of the materials and about a third of the energy consumed by the world economy. Construction activities contributed over 35% of total global CO2 emissions in 1999. According to the Green Building Council of Australia Building waste is 40% of all waste going to landfill in Australia. It is essential we learn to live with nature and change our ways

7 One Planet, Many People, Many Interconnected Problems
Global Sustainability Alliance Partners are in the BIGGEST Business on the Planet – Economic Solutions to our Energy, Global Warming, Water and Waste Problems.

8 Global Fresh Water A finite resource Water-stress
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

9 Australia’s Water Problems
Australia is the driest inhabited continent in the world - only Antarctica gets less rain. Most of Australia has experienced drought under El Nino conditions for the past few years. Some major cities are seriously short of water. Yet giga litres of stormwater go into our coastal water ways every year carrying with it significant levels of pollution.

10 Stormwater = Rainwater + Pollution
Pollution comes from many different sources, however the two main sources are Point and Non-point sources. Stormwater is the major cause of reduction in water quality in rivers and the destruction of marine environments. Stormwater is NOT supposed to include sewerage! Pollution is why it is not a good idea to eat too many fish from many areas near cities Why mix rainwater and pollution?

11 Point and Non-Point Source Pollution
Point Source Pollution Point source pollution is when high levels of pollution enter a water system such as a wetland or river from one source, such as a factory, mine, sewage plant or garbage dump. Point source pollution is easy to trace. Non-Point Source Pollution Non-point source pollution is when levels of pollution enter a water system at various points and from various sources. This type of pollution is the most difficult to monitor and manage. The most common non-point source of stormwater pollution comes from local residents throughout a catchment.

12 Stormwater = Rainwater + Pollution
Source: thesource.melbournewater.com.au/.../river.htm

13 Sources 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:

14 Types of Pollution (1) Litter Pedestrians dropping food wrappers , cigarette butts etc. Motorists tossing litter from their vehicles. Litter from building sites. Industry packaging and other waste materials. Trucks with uncovered loads which blows onto roads. Macro Leaves Deciduous trees drop their leaves in Autumn creating a significant pollution problem in the waterways. Excessive leaves enter the stormwater system, choking waterways, reducing sunlight penetration and decomposing, causing nitrate pollution. This can create low oxygen conditions, killing animals. Macro Micro and Molecular Sediment Sediment is a major source of pollution in stormwater. Excessive sediment chokes creek beds and reduces flow capacity as well as de- grading natural ecosystems by stifling aquatic plants and animals and blocking sunlight. Sources include construction sites, erosion along streams and rivers, soil erosion from poor management of agricultural activities, and road runoff. Micro Soaps and detergents Detergent and soaps tend to contain high levels of phosphorus. This chemical is a limiting factor in plant growth. Excessive amounts provide the nutrients required to fuel an algal bloom. Molecular Modified from: EPA stormwater code of practice from

15 Types of Pollution (2) Oil and grease Enter the stormwater system via leaking engines, deliberate dumping and accidental spills. High levels of oil can directly threaten the life of animals in waterways. Macro and Molecular Nutrients Enter the stormwater system via runoff from parks and farms that use fertiliser, effluent from sewage treatment plants and septic tanks, chemical and fertiliser spills, and rotting vegetation. Nutrients provide fuel for algal blooms which choke waterways, cut off light and hence kill off aquatic ecosystems. Excessive nitrogen is one of the major factors in the die back of seagrass in our rivers. Molecular Faecal coliforms Enter the stormwater system by contamination with human or animal wastes. The main sources are dogs, horses, septic tanks and farm animals. Macro Micro and Molecular Heavy Metals Lead, zinc and copper are the major heavy metals entering the stormwater system via roads, and in the case of lead, via exhaust. Elevated levels can cause death and mutation in animal populations. Modified from: EPA stormwater code of practice from

16 Roads Interrupt Natural Drainage
We have dissected the landscape with roads and no matter what kind, they modify the drainage network. Roads themselves are impervious and also capture water. Stormwater from buildings and from properties usually goes to the same drainage system. Stormwater = Rainwater + Pollution Various sources! Source: Keith Stichler, CBF

17 Roads are the Drainage Network
And represent a huge wasted catchment

18 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.

19 Purifying Water Pervious pavements filter water falling on them releasing it slowly to sub-surface drains or aquifers and finally the sea. There is little or now surface run-off to carry rubbish into drains and streams. Water quality is purified by the sub-pavement acting as a giant biofiliter allowing bacteria and oxygen to do their work and because surface rubbish does not contaminate it. 

20 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.

21 Speed, 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”

22 Traps Do Not Stop Micro and Molecular Pollution
Source Traps are useless for stopping most pollutants other than those that are unsightly

23 The Functions of Roads Roads are the veins, arteries and lymphatic system of cities. They provide The network for The transport of resources and wastes Drainage The route for all services Water Sewerage Electricity Gas Telephone etc. Many different people are involved

24 Current Road Designs are Not Sustainable
Drainage and Traffic Engineers Sewerage Engineers Traffic Engineers Management Hydraulic Engineers Environmental Scientists Gas Engineers Ratepayers Telecommunication Engineers Geo Technical Engineers Electrical Engineers The various groups with an interest in roads do not work together holistically How often do you see the same section of road dug up repeatedly in quick succession?

25 Changing the Road Paradigm
Roads and associated services as they are today have not been thought out. They have evolved. In the past the agencies that are responsible for these networks and services have more or less acted independently of each other resulting in Wasted Resources Additional Cost How often do you see different crews digging up the same bit of road? This is not sustainable! You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete. – Buckminster Fuller

26 Building a New Model The engineering paradigm too prevalent amongst the road building fraternity is: “Roads are for vehicles” “water on roads in dangerous” “collect it and get rid of it as quickly as possible” Given the current water crisis can this limited thinking be allowed to continue? Only a small % of water reticulated through a community is used for drinking. Most is used for washing, laundry, flushing toilets or watering gardens. Perhaps the water caught by our road drainage systems could be used?

27 Heads First for Action Water, CO2, waste and many other issues are mostly in our heads. We must first think differently then Act differently! Roads are not just for traffic They set drainage patterns Carry services under them Define wildlife zones Prevent natural percolation to aquifers etc. Roads in the future will have to be: Holistically designed Take into account previously unintended outcomes such as local drainage alteration and pollution. Capture desperately needed water Our model, measure and mentor for change must be nature. John Harrison with pervious pavement. Photographer Peter Boyer

28 Our Guide - Biomimicry - Geomimicry
John Harrison Presentation AASMIC Conference Our Guide - Biomimicry - Geomimicry The term biomimicry was popularised by the book of the same name written by Janine Benyus Biomimicry is a method of solving problems that uses natural processes and systems as a source of knowledge and inspiration. It involves nature as model, measure and mentor. Geomimicry is similar to biomimicry but models geological rather than biological processes. The theory behind biomimicry is that natural processes and systems have evolved over several billion years through a process of research and development commonly referred to as evolution. A reoccurring theme in natural systems is the cyclical flow of matter in such a way that there is no waste of matter and very little of energy. Geomimicry is a natural extension of biomimicry and applies to geological rather than living processes We can learn from nature about how we should construct roads

29 Pervious Concrete Pavement - Addressing the Issues
Pervious pavement is a unique and effective means of addressing environmental issues Image source:

30 TecEco Permecocrete - Thinking About Water and Roads
Pavements are not just for vehicles. They must do much more CO2 CO2 CO2 CO2 CO2 CO2 Cooling Evaporation Sequestration Cleansing microbial activity and oxygenation Moisture retention The substrate must be properly designed Optional groundwater recharge Optional impervious layer, underground drainage and storage. Dual water supply or parks etc. only.

31 Holistic Roads for the Future
In Australia we run many duplicate services down each side of a road. Given the high cost of installing infrastructure it would be smarter to adopt a system whereby services run down the middle of a road down what amount to giant box culverts. Conventional bitumen or concrete footpath pavement Pervious 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. Impermeable layer (concrete or plastic liner) angling for main flow towards collection drains Collection drains to transport drain or pipe in service conduit at intervals Possible leakage to street trees and underground aquifers Its time for a road re think!

32 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 feature keeps water clean All rainwater redirected to pavement filter. Permecocrete pervious pavement Pump Water storage e.g. under drive

33 Placing Pervious Pavement
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34 Finishing Pervious Pavement
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35 Laying Pervious Pavement
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36 Cross Section Pervious Pavement
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37 TecEco Permecocrete TecEco Eco-Cement Permecocrete concrete pavement technology Is a unique and effective means to address important environmental issues and support sustainable growth. Environmental Advantages Slows down the rate of transport to rivers and streams purifying water replenishing natural aquifers. Reducing salinity Eco-Cement Pervious concrete sequesters carbon dioxide Non Environmental Advantages Safer for traffic Improved acoustic properties Reduces building maintenance Cooler suburbs Reduced drainage infrastructure costs Reduces the need for culverts, pies drains, retention ponds, swales, and other storm water management devices. Less watering of street trees

38 Environmental Advantages
Reduced volume and rate of runoff Pervious pavement would allow the replenishment of aquifers and reduced the cost of infrastructure to carry water out to sea as the volume and rate of flow would be less. Not as many pollutants, rubbish and debris would be transported reducing waterway pollution. Cleaner water - less pollution A pervious pavement with integral bacteria would improve water quality entering aquifers, streams and rivers. The critical "first flush" of pollutants would be sent rapidly into the cross-section where constantly available sources of bacteria and microbes exist and have sufficient air exchange capability to maintain themselves and perform their cleaning functions. Pervious pavements could act as both pavements and bio-filters at the same time. Replenish aquifers or provide water Reducing salinity by replenishment with fresh water. Permecocretes are also carbon sinks.

39 Non Environmental Advantages
Pervious pavements do not collect puddles of water making it safer for traffic Pervious pavements are quieter as the absorb sound Pervious pavement prevent the ground drying out under building cracking them. Pervious pavements made with TecEco Eco-Cements are more durable Cities with pervious pavement are cooler They can transpire naturally (loosing latent heat of evaporation) Eco-Cement Permecocrete concrete pavement has a lighter albido Given economies of scale Tec-Eco Permecocrete pavement should cost less Less infrastructure Reduced need for culverts, pipes, retention ponds, swales, and other stormwater management devices

40 Hot City Syndrome and Pervious Pavement
John Harrison Presentation AASMIC Conference Hot City Syndrome and Pervious Pavement Ever walked up a pebble beach on a hot sunny day? The heat held by the stones can be unbearable! It’s the same in large cities. There are so many materials with high specific heat that during hot sunny weather and with no natural transpiration, due to the fact that we have paved all the ground, large cities just get hotter and hotter. As architects, engineers and designers of cities we need to come to grips with the macro impacts of the materials we use. Hot city syndrome is one of a number of man made phenomena that the use of pervious Eco-Cement pavements will reduce. The solution is to let the ground breathe and pervious pavements do this. Evaporation after all is still the principle behind many cooling systems – so why do we pave the ground and prevent moisture entering or exiting?

41 Solving the Water Problem
Collecting Rain Water Using Pervious Pavement Solving the Water Problem 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.

42 The Clogging Myth - Cleaning Pervious Pavement
Those who remain sceptics please also note that it is better to have pollution collected from a pervious pavement by machinery than pollute our coastal waterways Frimokar Australia high pressure jet and suction cleaning in action The experience of many engineers is that with relatively minor control and maintenance clogging will not reduce the infiltration rate below a design rate within the lifecycle of the pavement. Like any other kind of surface, pervious pavements should be cleaned periodically to remove debris and water under pressure combined with suction is most effective.

43 Making Pervious Pavement
John Harrison Presentation AASMIC Conference Making 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.

44 Salinity Increasing salinity is one of the most significant environmental problems facing Australia. While salt is naturally present in many of our landscapes, European farming practices which replaced native vegetation with shallow-rooted crops and pastures have caused a marked increase in the expression of salinity in our land and water resources. Rising groundwater levels, caused by these farming practices, are bringing with them dissolved salts which were stored in the ground for millennia. Salt is being transported to the root-zones of remnant vegetation, crops, pastures, and directly into our wetlands, streams and river systems. The rising water tables are also affecting our rural infrastructure including buildings, roads, pipes and underground cables. Salinity and rising water tables incur significant and costly impacts. According to the Australian National Action plan (http://www.napswq.gov.au/publications/salinity.html#how) and CSIRO web sites there are two main causes of salinity irrigation salinity dryland salinity Caused by clearing Caused by evaporation

45 Irrigation Salinity According to the Australian National Action plan website at how salinity occurs through irrigation is because water soaks through the soil area where the plant roots grow, adding to the existing water. The additional irrigation water causes the underground water-table to rise, bringing salt to the surface. When the irrigated area dries and the underground water-table recedes, salt is left on the surface soil. Each time the area is irrigated this salinity process is repeated. The government website quoted above fails to state the obvious which is that: Every time water percolates through rocks and soil it picks up more salts. In the Murray Darling system a lot of irrigation water returns on the surface and underground to the river and is used again for irrigation, exacerbating the problem The sequence forestry-agriculture-irrigation-salinity-aridity has destroyed many civilisations – will ours be next? Figure from the Australian National Action plan website at

46 Dryland Salinity – Caused by Clearing
According to the Australian National Action plan website at 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

47 Dryland Salinity – Caused by Evaporation
Salinity also also develops as excess water moves to and collects in poorly drained discharge zones. The buildup of excess water brings dissolved salts to the surface where evaporation concentrates them. Figure modified from the Manitoba Agriculture Web Site

48 Salinity, 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 Salty water Fresh water Salinity can be rectified by a combination of: Deep drainage. Mulching to increase humidity at ground level and reduce evaporative loss. Planting deep rooted salt tolerant species and leaving native belts that reduce the overall rate of evapotranspiration of the fresh water lens on top of ground water. Pervious rather than sealed surfaces (TecEco permecocrete pervious pavement). Allowing capture of fresh water rather than run off. Maximising capture and use of fresh water and minimising irrigation water. Replenishing aquifers with fresh rain water rather than recycled water through irrigation.

49 How Our Theories Differ on Salinity
Many websites including the CSIRO and Australian government website on salinity when discussing salinity that is not clearly related to irrigation and the re-use of water seem to think that the problem relates to reduced evapotranspiration with agriculture and rising water tables that bring “ancient” salts to the surface. We think this analysis wrong. When land is cleared natural mulches and soil humus that retain water and reduce evaporation and rate of run off at the surface of soils are removed. As a consequence what then happens is that fresh water does not enter the water table when it rains. It runs off into our rivers. According to the water dynamic discussed above it also picks up salt and pollution. Gradually during dry periods the fresh water lens on top of our aquifers is used up and the saltier water underneath remains. Reused irrigation water brings with it the salt it has picked up along the way.

50 TecEco 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.

51 Cities as Profitable Carbon Sinks?
THERE is a way to make our city streets as green as the Amazon rainforest. Almost every aspect of the built environment, from bridges to factories to tower blocks, and from roads to sea walls, could be turned into structures that soak up carbon dioxide- the main greenhouse gas behind global warming. All we need to do is change the way we make cement. Pearce, F. (2002). "Green Foundations." New Scientist 175(2351):

52 We Must Learn to Recycle Everything Including CO2
During earth's geological history large tonnages of carbon were put away as limestone and other carbonates and as coal and petroleum by the activity of plants and animals. Sequestering carbon in calcium and magnesium carbonate materials and other wastes in pervious pavement mimics nature. CO2 C Waste Pervious pavement 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”

53 John Harrison Presentation AASMIC Conference
Geomimicry There are 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 billions of years of sequestration and cover 7% of the crust.

54 Geomimicry for Planetary Engineers?
John Harrison Presentation AASMIC Conference 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

55 Geomimicry for Planetary Engineers?
John Harrison Presentation AASMIC Conference Geomimicry for Planetary Engineers? Such a paradigm shift in resource usage will not occur because it is the right thing to do. It can only happen economically. We must put an economic value on carbon to solve global warming by Inventing new technical paradigms such as offered by the Global Sustainability Alliance in Gaia Engineering. Evolving culturally to effectively use these technical paradigms By using carbon dioxide and other wastes as a building materials we could economically reduce their concentration in the global commons. Materials are very important

56 Economically Driven Sustainability
John Harrison Presentation AASMIC Conference Economically Driven Sustainability New, more profitable technical paradigms are required that result in more sustainable and usually more efficient moleconomic flows that mimic natural flows or better, reverse our damaging flows. ECONOMICALLY DRIVEN SUSTAINABILITY Our approach must not only be holistic, but also economic if we are to have any hope of success. Working for sustainability market forces will make all the difference. The challenge is to move the supply and demand of resources towards more sustainable outcomes by stimulating and harnessing human behaviours which underlay economic demand phenomena, through cultural change push by governments and other leaders, and real improvement in technical and other properties as I will explain in the next slide. Sustainable processes like the new TecEco technologies are more efficient and therefore more economic. $ - ECONOMICS - $ Change is only possible economically. It will not happen because it is necessary or right.

57 Changing the Technology Paradigm
John Harrison Presentation AASMIC Conference Changing the Technology Paradigm It is not so much a matter of “dematerialisation” as a question of changing the underlying moleconomic flows. We need materials that require less energy to make them, do not pollute the environment with CO2 and other releases, last much longer and that contribute properties that reduce lifetime energies. The key is to change the technology paradigms “By enabling us to make productive use of particular raw materials, technology determines what constitutes a physical resource1” Pilzer, Paul Zane, Unlimited Wealth, The Theory and Practice of Economic Alchemy, Crown Publishers Inc. New York.1990

58 Cultural Change The media have a growing role 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

59 Sustainability is Where Culture and Technology Meet
John Harrison Presentation AASMIC Conference Sustainability 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 CULTURAL CHANGE AND PARADIGM SHIFTS IN TECHNOLOGY Changes in the market interaction of demand and supply reducing energy and resource usage and detrimental linkages with the planet can be achieved through cultural change and innovative changes in the technical paradigm. 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.

60 John Harrison Presentation AASMIC Conference
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 ~= 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

61 John Harrison Presentation AASMIC Conference
Huge Potential for Sequestration and Waste Utilisation in the Built Environment Reducing the impact of the take and waste phases of the techno-process by. including carbon in materials they are potentially carbon sinks. including wastes for physical properties as well as chemical composition they become resources. re engineering materials to reduce the lifetime energy of buildings A durable low pH high bonding binder system is required for effective waste utilisation such as TecEco Tec and Eco-Cements Many wastes including CO2 can contribute to physical properties reducing lifetime energies CO2 CO2 UTILISING WASTE IN CITIES TecEco advocate the development of materials that include waste based on physical as well as chemical properties and that reduce the lifetime energy of buildings by introducing new properties. CO2 C CO2 Waste Pervious pavement

62 Gaia Engineering Flowchart
Portland Cement Manufacture CaO TecEco Tec-Kiln Industrial CO2 MgO Clays Fresh Water TecEco Cement Manufacture MgCO3 and CaCO3 “Stone” Brine or Sea water Extraction Waste Acid or Bitterns Eco-Cements Tec-Cements Valuable Commodity Salts or hydrochloric acid. Building components & aggregates Extraction inputs and outputs depending on method chosen Other waste Built Environment Building waste

63 The 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

64 The Gaia Engineering Process
John Harrison Presentation AASMIC Conference The 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: Carbonate building materials, potable water, valuable commodity salts. Carbonate building components CO2 CO2 Solar or solar derived energy CO2 TecEco Kiln TecEco MgCO2 Cycle CO2 Eco-Cement MgO MgCO3 Extraction Process 1.29 gm/l Mg .412 gm/l Ca Coal Fossil fuels Carbon or carbon compounds Magnesium compounds Oil

65 John Harrison Presentation AASMIC Conference
TecEco Cements SUSTAINABILITY DURABILITY STRENGTH TECECO 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.

66 John Harrison Presentation AASMIC Conference
TecEco Formulations Tec-cements (5-15% MgO, 85-95% OPC) contain more Portland cement than reactive magnesia. Reactive magnesia hydrates in the same rate order as Portland cement forming Brucite which uses up water reducing the voids:paste ratio, increasing density and possibly raising the short term pH. Reactions with pozzolans are more affective. After all the Portlandite has been consumed Brucite controls the long term pH which is lower and due to it’s low solubility, mobility and reactivity results in greater durability. Other benefits include improvements in density, strength and rheology, reduced permeability and shrinkage and the use of a wider range of aggregates many of which are potentially wastes without reaction problems. Eco-cements (15-95% MgO, 85-5% OPC) contain more reactive magnesia than in tec-cements. Brucite in permeable materials carbonates forming stronger fibrous mineral carbonates and therefore presenting huge opportunities for waste utilisation and sequestration. Enviro-cements (5-15% MgO, 85-95% OPC) contain similar ratios of MgO and OPC to eco-cements but in non permeable concretes brucite does not carbonate readily. Higher proportions of magnesia are most suited to toxic and hazardous waste immobilisation and when durability is required. Strength is not developed quickly nor to the same extent. TECECO FORMULATIONS We have three main formulations to date, Tec-Cements which are really pre-mix concretes, Eco-Cements which have much more magnesia in them and set by carbonation in pervious substrates and Enviro-Cements which are relatively weak as they do not carbonate, they are however potentially suitable for toxic and hazardous wastes.

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

68 Tec & Eco-Cement Theory
John Harrison Presentation AASMIC Conference Tec & Eco-Cement Theory Portlandite (Ca(OH)2) is too soluble, mobile and reactive. It carbonates, reacts with Cl- and SO4- and being soluble can act as an electrolyte. TecEco generally (but not always) remove Portlandite using the pozzolanic reaction and TecEco add reactive magnesia which hydrates, consuming significant water and concentrating alkalis forming Brucite which is another alkali, but much less soluble, mobile or reactive than Portlandite. In Eco-Cements brucite carbonates forming hydrated compounds with greater volume

69 Why Add Reactive Magnesia?
John Harrison Presentation AASMIC Conference 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

70 Why do Eco-Cements use Magnesium Compounds?
John Harrison Presentation AASMIC Conference 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 WHY MAGNESIUM COMPOUNDS Because magnesium has a low molecular weight, proportionally a much greater amount of CO2 is released or captured. This, together with the high proportion of water in the binder is what makes construction the built environment out of CO2 and water so exciting. Imagine the possibilities if CO2 could be captured during the manufacture of eco-cement!

71 Strength with Blend & Porosity
John Harrison Presentation AASMIC Conference Strength with Blend & Porosity Tec-cement concretes Eco-cement concretes High Porosity Enviro-cement concretes High OPC High Magnesia STRENGTH ON ARBITARY SCALE 1-100

72 Solving Waste & Logistics Problems
John Harrison Presentation AASMIC Conference Solving Waste & Logistics Problems TecEco cementitious composites represent a cost affective option for using non traditional aggregates from on site reducing transports costs and emissions use and immobilisation of waste. Because they have lower reactivity less water lower pH Reduced solubility of heavy metals less mobile salts greater durability. denser. impermeable (tec-cements). dimensionally more stable with less shrinkage and cracking. homogenous. no bleed water. TecEco Technology - Converting Waste to Resource

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

74 John Harrison Presentation AASMIC Conference
Eco-Cements Have high proportions of reactive magnesium oxide Carbonate like lime Generally used in a 1:5-1:12 paste basis because much more carbonate “binder” is produced than with lime MgO + H2O <=> Mg(OH)2 Mg(OH)2 + CO2 + H2O <=> MgCO3.3H2O <=> molar mass (at least!) gas <=> 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”.

75 Carbonation is Proportional to Porosity
Carbonation Rate Macro Porosity

76 Carbonation is Proportional to Time
100 % % Carbonation 180 days Time

77 CO2 Abatement in Eco-Cements
John Harrison Presentation AASMIC Conference CO2 Abatement in Eco-Cements For 85 wt% Aggregates 15 wt% Cement Portland Cements 15 mass% Portland cement, 85 mass% aggregate Emissions .32 tonnes to the tonne. After carbonation. Approximately .299 tonne to the tonne. No Capture 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate. Emissions .37 tonnes to the tonne. After carbonation. approximately .241 tonne to the tonne. Capture CO % mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate. Emissions .25 tonnes to the tonne. After carbonation. approximately tonne to the tonne. Capture CO2. Fly and Bottom Ash 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate. Emissions .126 tonnes to the tonne. After carbonation. Approximately .113 tonne to the tonne. 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 CO2 ABATEMENT IN AN ECO-CEMENT BLOCK This slide shows that for an eco-cement concrete in a block which is 15% eco-cement if the eco-cement contains 75% reactive magnesia and with capture of CO2 during the manufacturing process net emissions are less than a third as much. .299 > .241 >.140 >.113 Bricks, blocks, pavers, mortars and pavement made using eco-cement, fly and bottom ash (with capture of CO2 during manufacture of reactive magnesia) have 2.65 times less emissions than if they were made with Portland cement.

78 Eco-Cement Strength Development
John Harrison Presentation AASMIC Conference Eco-Cement Strength Development Eco-cements gain early strength from the hydration of PC. Later strength comes from the carbonation of brucite forming an amorphous phase, lansfordite and nesquehonite. Strength gain in eco-cements is mainly microstructural because of More ideal particle packing (Brucite particles at 4-5 micron are under half the size of cement grains.) The natural fibrous and acicular shape of magnesium carbonate minerals which tend to lock together. More binder is formed than with calcium Total volumetric expansion from magnesium oxide to lansfordite is for example volume 811%. Mg(OH)2 + CO2  MgCO3.5H2O From air and water

79 Eco-Cement Strength Gain Curve
John Harrison Presentation AASMIC Conference Eco-Cement Strength Gain Curve Eco-cement bricks, blocks, pavers and mortars etc. take a while to come to the same or greater strength than OPC formulations but are stronger than lime based formulations.

80 Chemistry of Eco-Cements
John Harrison Presentation AASMIC Conference Chemistry of Eco-Cements There are a number of carbonates of magnesium. The main ones appear to be an amorphous phase, lansfordite and nesquehonite. The carbonation of magnesium hydroxide does not proceed as readily as that of calcium hydroxide. Gor Brucite to nesquehonite = kJ.mol-1 Compare to Gor Portlandite to calcite = 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.

81 John Harrison Presentation AASMIC Conference
Eco-Cement Reactions John Harrison Presentation AASMIC Conference

82 Eco-Cement Micro-Structural Strength
John Harrison Presentation AASMIC Conference Eco-Cement Micro-Structural Strength

83 John Harrison Presentation AASMIC Conference
Carbonation Eco-cement is based on blending reactive magnesium oxide with other hydraulic cements and then allowing the Brucite and Portlandite components to carbonate in permeable materials such as concretes blocks and mortars. Magnesium is a small lightweight atom and the carbonates that form contain proportionally a lot of CO2 and water and are stronger because of superior microstructure. The use of eco-cements for block manufacture, particularly in conjunction with the kiln also invented by TecEco (The Tec-Kiln) would result in sequestration on a massive scale. As Fred Pearce reported in New Scientist Magazine (Pearce, F., 2002), “There is a way to make our city streets as green as the Amazon rainforest”. Ancient and modern carbonating lime mortars are based on this principle

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

85 CO2 Abatement in Eco-Cements
John Harrison Presentation AASMIC Conference CO2 Abatement in Eco-Cements For 85 wt% Aggregates 15 wt% Cement Portland Cements 15 mass% Portland cement, 85 mass% aggregate Emissions .32 tonnes to the tonne. After carbonation. Approximately .299 tonne to the tonne. No Capture 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate. Emissions .37 tonnes to the tonne. After carbonation. approximately .241 tonne to the tonne. Capture CO % mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate. Emissions .25 tonnes to the tonne. After carbonation. approximately tonne to the tonne. Capture CO2. Fly and Bottom Ash 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate. Emissions .126 tonnes to the tonne. After carbonation. Approximately .113 tonne to the tonne. 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 CO2 ABATEMENT IN AN ECO-CEMENT BLOCK The above slide shows that for an eco-cement concrete in a block which is 15% eco-cement if the eco-cement contains 75% reactive magnesia and with capture of CO2 during the manufacturing process and the use of a pozzolan after carbonation net emissions are less than a third as much. .299 > .241 >.140 >.113 Bricks, blocks, pavers, mortars and pavement made using eco-cement, fly and bottom ash (with capture of CO2 during manufacture of reactive magnesia) have 2.65 times less emissions than if they were made with Portland cement.

86 John Harrison Presentation AASMIC Conference
TecEco Cement LCA TecEco Concretes will have a big role post Kyoto as they offer potential sequestration as well as waste utilisation TECECO LCA MODEL For more information on the contribution our Tec and Eco-Cements can make to the global carbon balance please consult our LCA model under tools on the web site. The TecEco LCA model is available for download under “tools” on the web site

87 Net Emissions/Sequestration Compared
(Gaia Engineering Assumed)

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

89 John Harrison Presentation AASMIC Conference
A Post – Carbon Age ECO-CEMENTS The main magnesium carbonate that form in eco-cement is nesquehonite which is 83 mass % water and CO2 – cheap binder? Lansfordite, another mineral that forms has even more water in it! Magnesium carbonates are generally fibrous and acicular and therefore add microstructural strength. The long term pH is much lower than Portland cement concretes. Combined with the fact that magnesium minerals seem to stick well to other materials the result is that a high proportion of wastes can be included. As mentioned earlier TecEco cements are generally also much more durable. Materials that last longer are much more sustainable We all use carbon and wastes!

90 Eco-Cement compared to Carbonating Lime Mortar.
John Harrison Presentation AASMIC Conference Eco-Cement compared to Carbonating Lime Mortar. The underlying chemistry is very similar however eco-cements are potentially superior to lime mortars because: The calcination phase of the magnesium thermodynamic cycle takes place at a much lower temperature Magnesium minerals are generally more fibrous and acicular than calcium minerals and hence a lot stronger. Water forms part of the binder minerals that forming making the cement component go further. Magnesium hydroxide in particular and to some extent the carbonates are less reactive and mobile and thus much more durable. A less reactive environment with a lower long term pH. (around 10.5 instead of 12.35) Because magnesium has a low molecular weight, proportionally a much greater amount of CO2 is captured. Carbonation in the built environment would result in significant sequestration because of the shear volumes involved. Carbonation adds considerable strength and some steel reinforced structural concrete could be replaced with fibre reinforced permeable carbonated concrete. ECO-CEMENTS COMPARED TO CARBONATING LIME MORTARS 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.

91 A More Sustainable Built Environment
John Harrison Presentation AASMIC Conference A More Sustainable Built Environment CO2 + H2O => Hydrocarbons compounds using bacteria CO2 OTHERWASTES CO2 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 GREENSOLS MgO ECO-CEMENT CONCRETES MAGNESIUM CARBONATE TECECO KILN RECYCLED BUILDING MATERIALS “There is a way to make our city streets as green as the Amazon rainforest”. Fred Pearce, New Scientist Magazine TECECO’S DREAM Our dream is to create cities that mimic nature in that have a balance of carbon, other wastes and energy. SUSTAINABLE CITIES

92 Conclusion Pervious pavements made with TecEco Eco-Cements would utilise a considerable proportion of wastes such as fly ash and as they would carbonate, provide substantial abatement. Water entering aquifers, streams and rivers would be of higher quality and carry less macro pollutants. Cities with pervious pavements would be safer for traffic, be cleaner and have less pollution Fresh water replenishment of aquifers would reduce salinity and reverse falling water tables. Pervious pavements could provide a means for water capture with in situ cleansing thereby solving the water crisis in our cities


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