Presentation on theme: "Presentation downloadable from www.tececo.com 1 Pervious Pavement We can't solve problems by using the same kind of thinking we used when we created them.""— Presentation transcript:
Presentation downloadable from www.tececo.com 1 Pervious 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
Presentation downloadable from www.tececo.com 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. 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.
Presentation downloadable from www.tececo.com 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)
Presentation downloadable from www.tececo.com 4 Australia Before Settlement In years gone by grassland and forest covered the land
Presentation downloadable from www.tececo.com 5 Australia 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 environment are many and damaging
Presentation downloadable from www.tececo.com 6 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 pervious Tec- Pavement solution.
Presentation downloadable from www.tececo.com 7 Australia 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 of sequestering carbon dioxide and utilising wastes to create our techno - world It is essential we learn to live with nature and change our ways
Presentation downloadable from www.tececo.com 8 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.
Presentation downloadable from www.tececo.com 9 Global Fresh Water A finite resource –Population rising –Per capita use rising Water-stress –1/3 world's population –By 2025, 2/3 due to global warming. –1 person in 5 do not have access to safe drinking water Yet water is the most common substance on the planet. –Water covers 70% of the surface –Only =~ 1% is potable
Presentation downloadable from www.tececo.com 10 Australias 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.
Presentation downloadable from www.tececo.com 11 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?
Presentation downloadable from www.tececo.com 12 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.
Presentation downloadable from www.tececo.com 14 Sources and Types of Pollution Land usesTypes of pollution Rural/agricultural &market gardens Silt, pesticides, fertilisers, livestock faeces. Residential properties & gardens Detergent, pesticides, fertiliser, dog faeces, leaf litter. Industrial areas Industrial runoff & acidity Roads & carparks Oil, petrol, heavy metals, leaf litter Shopping centres Litter, shopping bags, junk food containers Service stations Detergents, oil, petrol Construction/building sites Silt, paint, packaging, bricks Sewage treatment plant Bacteria, phosphorus, nitrates Parks and reserves Litter, dog and cat faeces, grass cuttings, leaves Adapted from: www.cwmb.sa.gov.au/kwc/section1/1-24.htm
Presentation downloadable from www.tececo.com 15 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. 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
Presentation downloadable from www.tececo.com 16 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
Presentation downloadable from www.tececo.com 17 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 Keith Stichler, CDR Various sources!
Presentation downloadable from www.tececo.com 18 Roads are the Drainage Network And represent a huge wasted catchment
Presentation downloadable from www.tececo.com 19 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.
Presentation downloadable from www.tececo.com 20 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.
Presentation downloadable from www.tececo.com 21 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.
Presentation downloadable from www.tececo.com 22 Speed, 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
Presentation downloadable from www.tececo.com 23 Traps 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
Presentation downloadable from www.tececo.com 24 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
Presentation downloadable from www.tececo.com 25 Current Road Designs are Not Sustainable Traffic 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
Presentation downloadable from www.tececo.com 26 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
Presentation downloadable from www.tececo.com 27 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 for these purposes.
Presentation downloadable from www.tececo.com 28 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
Presentation downloadable from www.tececo.com 29 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
Presentation downloadable from www.tececo.com 30 Pervious Concrete Pavement - Addressing the Issues Image source: http://www.perviouspavement.org/ Pervious pavement is a unique and effective means of addressing environmental issues
Presentation downloadable from www.tececo.com 31 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 CO 2 Sequestration
Presentation downloadable from www.tececo.com 32 Holistic 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.
Presentation downloadable from www.tececo.com 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 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
Presentation downloadable from www.tececo.com 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.
Presentation downloadable from www.tececo.com 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
Presentation downloadable from www.tececo.com 40 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! Its the same in large cities. There are so many materials with high specific heat that during hot sunny weather and with no natural transpiration, due to the fact that we have paved all the ground, large cities just get hotter and hotter. As architects, engineers and designers of cities we need to come to grips with the macro impacts of the materials we use. Hot city syndrome is one of a number of man made phenomena that the use of pervious Eco-Cement pavements will reduce. The solution is to let the ground breathe and pervious pavements do this. Evaporation after all is still the principle behind many cooling systems – so why do we pave the ground and prevent moisture entering or exiting?
Presentation downloadable from www.tececo.com 41 Solving the Water Problem Collecting Rain Water Using Pervious Pavement An unknown but huge quantity of water is drained away to sea taking with it polluting substances and articles every time it rains on our cities. This rapid drainage of rain requires a high cost of investment in much larger drains than the original natural drainage replaced because water no longer percolates through natural vegetation and obstacles. –In urban and some agricultural areas water gets to the sea in hours not days! This water could be collected by permeable roads also acting as giant bio filters, subterranean reservoirs (the city of Alexandria had huge underground cisterns over 2000 years ago) and collection and redistribution network. An essential component of this paradigm is pervious pavement.
Presentation downloadable from www.tececo.com 42 TecEco 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
Presentation downloadable from www.tececo.com 43 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 feature keeps water clean Pump All rainwater redirected to pavement filter.
Presentation downloadable from www.tececo.com 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
Presentation downloadable from www.tececo.com 45 Irrigation 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.g ov.au/publications/sal inity.html#how
Presentation downloadable from www.tececo.com 46 Dryland Salinity – Caused by Clearing According to the Australian National Action plan website at http://www.napswq.gov.au/publications/salinity.html#how Dryland salinity is caused when the rising water-table brings natural salts in the soil to the surface. –The salt remains in the soil and becomes progressively concentrated as the water evaporates or is used by plants. –One of the main causes for rising water-tables is the removal of deep rooted plants, perennial trees, shrubs and grasses and their replacement by annual crops and pastures that do not use as much water. 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
Presentation downloadable from www.tececo.com 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 www.gov.mb.ca/.../soilwater/soil/fbe01s06.html
Presentation downloadable from www.tececo.com 48 Salinity, 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
Presentation downloadable from www.tececo.com 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. For more information please see our web site at http://www.tececo.com/sustainability.salinity_pollution.php
Presentation downloadable from www.tececo.com 50 The 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 waterways Frimokar Australia high pressure jet and suction cleaning in action
Presentation downloadable from www.tececo.com 51 We Must Learn to Recycle Everything Including CO2 During earth's geological history large tonnages of carbon were put away as limestone and other carbonates and as coal and petroleum by the activity of plants and animals. Sequestering carbon in calcium and magnesium carbonate materials and other wastes in pervious pavement mimics nature. In eco-cement blocks and mortars the binder is carbonate and the aggregates are preferably wastes Biomimicry - Geomimicry We all use carbon and wastes to make our homes! CO 2 C Waste CO 2 Pervious pavement
Presentation downloadable from www.tececo.com 52 Geomimicry 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 CO 2 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.
Presentation downloadable from www.tececo.com 53 Geomimicry for Planetary Engineers? Large tonnages of carbon were put away during earths geological history as limestone, dolomite, magnesite, coal and oil by the activity of plants and animals. –Shellfish built shells from it and –Trees turned it into wood. These same plants and animals wasted nothing –The waste from one was the food or home for another. Because of the colossal size of the flows involved the answer to the problems of greenhouse gas and waste is to use them both in building materials. Materials are very important
Presentation downloadable from www.tececo.com 54 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
Presentation downloadable from www.tececo.com 55 Economically Driven Sustainability New, more profitable technical paradigms are required that result in more sustainable and usually more efficient moleconomic flows that mimic natural flows or better, reverse our damaging flows. $ - ECONOMICS - $ Change is only possible economically. It will not happen because it is necessary or right.
Presentation downloadable from www.tececo.com 56 Changing the Technology Paradigm By enabling us to make productive use of particular raw materials, technology determines what constitutes a physical resource 1 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
Presentation downloadable from www.tececo.com 57 Cultural Change Al Gore (SOS) CSIRO reports STERN Report Lots of Talkfest IPCC Report Branson Prize Live Earth (07/07/07) The media have a growing role
Presentation downloadable from www.tececo.com 58 Sustainability is Where Culture and Technology Meet Increase in demand/price ratio for greater sustainability due to cultural change. # $ Demand Supply Increase in supply/price ratio for more sustainable products due to technical innovation. Equilibrium Shift ECONOMICS Greater 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
Presentation downloadable from www.tececo.com 59 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 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 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.
Presentation downloadable from www.tececo.com 60 Making Carbonate Building Materials to Solve the Global Warming Problem How much magnesium carbonate would have to be deposited to solve the problem of global warming? –12 billion tonnes CO2 ~= 22.99 billion tonnes magnesite –The density of magnesite is 3 gm/cm3 or 3 tonne/metre3 Thus 22.9/3 billion cubic metres ~= 7.63 cubic kilometres of magnesite are required to be deposited each year. Compared to the over seven cubic kilometres of concrete we make every year, the problem of global warming looks surmountable. If magnesite was our building material of choice and we could make it without releases as is the case with Gaia Engineering, we have the problem as good as solved! We must build with carbonate and waste Gaia Engineering offers technical paradigms allowing us to do so economically
Presentation downloadable from www.tececo.com 61 The Gaia Engineering Process Greensols Process Fossil fuels Solar or solar derived energy Oil MgO CO 2 Coal CO 2 MgCO 3 CO 2 Inputs: Atmospheric or smokestack CO 2, brines, waste acid, other wastes Outputs: Potable water, gypsum, sodium bicarbonate, salts, building materials, bottled concentrated CO 2 (for algal fuel production and other uses). Carbon or carbon compounds Magnesium compounds 1.29 gm/l Mg TecEco MgCO 2 Cycle TecEco Kiln Carbonate building components Eco-Cement
Presentation downloadable from www.tececo.com 62 TecEco Cements SUSTAINABILITY DURABILITYSTRENGTH 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.
Presentation downloadable from www.tececo.com 63 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 its low solubility, mobility and reactivity results in greater durability. –Other benefits include improvements in density, strength and rheology, reduced permeability and shrinkage and the use of a wider range of aggregates many of which are potentially wastes without reaction problems. Eco-cements (15-95% MgO, 85-5% OPC) –contain more reactive magnesia than in tec-cements. Brucite in 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.
Presentation downloadable from www.tececo.com 64 Tec & Eco-Cement Theory Many Engineering Issues are Actually Mineralogical Issues –Problems with Portland cement concretes are usually resolved by the band aid engineering fixes. e.g. Use of calcium nitrite, silanes, cathodic protection or stainless steel to prevent corrosion. Use of coatings to prevent carbonation. Crack control joins to mitigate the affects of shrinkage cracking. Plasticisers to improve workability. –Portlandite and water are the weakness of concrete TecEco remove Portlandite it and replacing it with magnesia which hydrates to Brucite. The hydration of magnesia consumes significant water
Presentation downloadable from www.tececo.com 65 Tec & Eco-Cement Theory Portlandite (Ca(OH) 2 ) is too soluble, mobile and reactive. –It carbonates, reacts with Cl - and SO 4 - 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 B rucite which is another alkali, but much less soluble, mobile or reactive than Portlandite. In Eco-Cements brucite carbonates forming hydrated compounds with greater volume
Presentation downloadable from www.tececo.com 66 Why Add Reactive Magnesia? To maintain the long term stability of CSH. –Maintains alkalinity preventing the reduction in Ca/Si ratio. To remove water. –Reactive magnesia consumes water as it hydrates to possibly hydrated forms of Brucite. To raise the early Ph. –Increasing non hydraulic strength giving reactions To reduce shrinkage. –The consequences of putting brucite through the matrix of a concrete in the first place need to be considered. To make concretes more durable Because significant quantities of carbonates are produced in permeable substrates which are affective binders. Reactive MgO is a new tool to be understood with profound affects on most properties
Presentation downloadable from www.tececo.com 67 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 CO 2 Because magnesium has a low molecular weight, proportionally a much greater amount of CO 2 is released or captured. A high proportion of water in the binder means that a little binder goes a long way
Presentation downloadable from www.tececo.com 68 Strength with Blend & Porosity High OPC High Magnesia High Porosity STRENGTH ON ARBITARY SCALE 1-100 Tec-cement concretes Eco-cement concretes Enviro-cement concretes
Presentation downloadable from www.tececo.com 69 Solving Waste & Logistics Problems TecEco cementitious composites represent a cost affective option for –using non traditional aggregates from on site reducing transports costs and emissions –use and immobilisation of waste. Because they have –lower reactivity less water lower pH –Reduced solubility of heavy metals less mobile salts –greater durability. denser. impermeable (tec-cements). dimensionally more stable with less shrinkage and cracking. –homogenous. –no bleed water. TecEco Technology - Converting Waste to Resource
Presentation downloadable from www.tececo.com 70 Eco-Cements Eco-cements are similar but potentially superior to lime mortars because: –The calcination phase of the magnesium thermodynamic cycle takes place at a much lower temperature and is therefore more efficient. –Magnesium minerals are generally more fibrous and acicular than calcium minerals and hence add microstructural strength. Water forms part of the binder minerals that forming making the cement component go further. In terms of binder produced for starting material in cement, eco-cements are much more efficient. Magnesium hydroxide in particular and to some extent the carbonates are less reactive and mobile and thus much more durable.
Presentation downloadable from www.tececo.com 71 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 + H 2 O Mg(OH) 2 Mg(OH) 2 + CO 2 + H 2 O MgCO 3. 3H 2 O 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 CO 2 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.
Presentation downloadable from www.tececo.com 72 Carbonation is Proportional to Porosity Carbonation Rate Macro Porosity
Presentation downloadable from www.tececo.com 73 Carbonation is Proportional to Time % Carbonation Time 100 % 180 days
Presentation downloadable from www.tececo.com 74 CO 2 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 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. Portland Cements 15 mass% Portland cement, 85 mass% aggregate Emissions.32 tonnes to the tonne. After carbonation. Approximately.299 tonne to the tonne..299 >.241 >.140 >.113 Bricks, blocks, pavers, mortars and pavement made using eco-cement, fly and bottom ash (with capture of CO 2 during manufacture of reactive magnesia) have 2.65 times less emissions than if they were made with Portland cement. Capture CO 2 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate. Emissions.25 tonnes to the tonne. After carbonation. approximately.140 tonne to the tonne. Capture CO 2. 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. For 85 wt% Aggregates 15 wt% Cement Greater Sustainability
Presentation downloadable from www.tececo.com 75 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 + CO 2 MgCO 3.5H 2 O From air and water
Presentation downloadable from www.tececo.com 76 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.
Presentation downloadable from www.tececo.com 77 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. – G o r Brucite to nesquehonite = - 38.73 kJ.mol-1 –Compare to G o r 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. G o r nesquehonite to magnesite = 8.56 kJ.mol-1 –But kinetically driven by desiccation during drying. Reactive magnesia can carbonate in dry conditions – so keep bags sealed! For a full discussion of the thermodynamics see our technical documents. TecEco technical documents on the web cover the important aspects of carbonation.
Presentation downloadable from www.tececo.com 78 Eco-Cement Reactions
Presentation downloadable from www.tececo.com 79 Eco-Cement Micro-Structural Strength
Presentation downloadable from www.tececo.com 80 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 pervious materials such as concretes blocks and mortars. –Magnesium is a small lightweight atom and the carbonates that form contain proportionally a lot of CO 2 and water and are stronger because of superior microstructure. The use of eco-cements for block manufacture, particularly in conjunction with the kiln also invented by TecEco (The Tec-Kiln) would result in sequestration on a massive scale. As Fred Pearce reported in New Scientist Magazine (Pearce, F., 2002), There is a way to make our city streets as green as the Amazon rainforest. Ancient and modern carbonating lime mortars are based on this principle
Presentation downloadable from www.tececo.com 81 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 pervious –requiring a coarse fraction to cause physical air voids and some vapour permeability. Coarse fractions are required in the aggregates used!
Presentation downloadable from www.tececo.com 82 CO 2 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 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. Portland Cements 15 mass% Portland cement, 85 mass% aggregate Emissions.32 tonnes to the tonne. After carbonation. Approximately.299 tonne to the tonne..299 >.241 >.140 >.113 Bricks, blocks, pavers, mortars and pavement made using eco-cement, fly and bottom ash (with capture of CO 2 during manufacture of reactive magnesia) have 2.65 times less emissions than if they were made with Portland cement. Capture CO 2 11.25% mass% reactive magnesia, 3.75 mass% Portland cement, 85 mass% aggregate. Emissions.25 tonnes to the tonne. After carbonation. approximately.140 tonne to the tonne. Capture CO 2. 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. For 85 wt% Aggregates 15 wt% Cement Greater Sustainability
Presentation downloadable from www.tececo.com 83 TecEco Cement LCA TecEco Concretes will have a big role post Kyoto as they offer potential sequestration as well as waste utilisation The TecEco LCA model is available for download under tools on the web site
Presentation downloadable from www.tececo.com 84 Net Emissions/Sequestration Compared (Gaia Engineering Assumed)
Presentation downloadable from www.tececo.com 85 Rosendale Concretes – Proof of Durability Rosendale cements contained 14 – 30% MgO A major structure built with Rosendale cements commenced in 1846 was Fort Jefferson near key west in Florida. Rosendale cements were recognized for their exceptional durability, even under severe exposure. At Fort Jefferson much of the 150 year-old Rosendale cement mortar remains in excellent condition, in spite of the severe ocean exposure and over 100 years of neglect. Fort Jefferson is nearly a half mile in circumference and has a total lack of expansion joints, yet shows no signs of cracking or stress. The first phase of a major restoration is currently in progress. More information from http://www.rosendalecement.net/rosendale_natural_cement_.html
Presentation downloadable from www.tececo.com 86 A Post – Carbon Age We all use carbon and wastes!
Presentation downloadable from www.tececo.com 87 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 CO 2 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.
Presentation downloadable from www.tececo.com 88 A More Sustainable Built Environment MAGNESIUM CARBONATE ECO-CEMENT CONCRETES SUSTAINABLE CITIES CO 2 PERMANENT SEQUESTRATION & WASTE UTILISATION (Man made carbonate rock incorporating wastes as a building material) Paretos principle - 80% of the build environment in non structural and could be carbonate from Greensols held together by Eco- Cements CO 2 MgO TECECO KILN RECYCLED BUILDING MATERIALS OTHER WASTES There is a way to make our city streets as green as the Amazon rainforest. Fred Pearce, New Scientist Magazine CO 2 + H 2 O => Hydrocarbons compounds using bacteria GREENSOLS CO 2
Presentation downloadable from www.tececo.com 89 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