BSPP 2013Q sec18a sustainability concepts v2011 · 2016-04-12 · Sustainability Concepts...

Sustainability Concepts

Australian Asphalt Pavement Association – 2011 1

SUSTAINABILITY CONCEPTS

1 INTRODUCTION There notes are based on work by John Lambert on “Greenhouse Gas and Climate Change” reports by the National Asphalt Pavement Association on the sustainability and greenhouse gas benefits of “Perpetual Pavements”, “Warm Mix Asphalt”, Porous & Open Graded Asphalt”, “Increasing the use of Recycled Pavements” and “Carbon Footprint”.

2 SUSTAINABILITY CONCEPTS

2.1 General

The concepts of sustainability arise from the definitions of sustainability which are many and varied within the dictionary definition of “The ability to maintain, support or endure”. For humans that can be considered “The potential for long-term maintenance of well being” which requires the stewardship and responsible planning and management of resources and spans environmental, economic and social parts.

In 1987 the United Nations sought to define the concept of sustainable development as “sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”

To date there is no universally accepted definition of the concepts although the vague "sustainability is improving the quality of human life while living within the carrying capacity of supporting eco-systems" conveys the general meaning.

Sustainability can be considered as “our responsibility to improve the quality of life, where we are challenged to:

1. Minimize our impacts on scarce resources to within their carrying capacity

2. Actively seek improvements with current systems

3. Seek different and innovative solutions with more sustainable outcomes”

2.2 Balance

The definitions have embedded some concept of balance of demand and supply, which needs reference as to where we are now and what demands will be put on sustainability into the future.

Figure 2.2 World Population Growth 10,000 BC to 2008


2 Australian Asphalt Pavement Association – 2011

To remain within the macro supporting capability of the earth the influences of population and the resultant consumption of natural resources and generation of waste needs to be in balance. With the increased benefits of good health care, improved incomes, reliable food distribution and reduced effects of petulance, plague, natural disasters and war, the world has experienced exponential population growth expecting 7 billion in 2012 and over 9 billion in 2050. Figure 1 World Population growth.

Figure 2 Human welfare and ecological footprints compared

The natural carrying capacity of the Earth under current conditions (2008) 2.1 global hectares per person, average consumption in 2008 was 2.7 global hectares or 30% more. Figure 2 Human welfare and economic footprints compared reflects on the position of Australia and the USA where high qualities of life link to big footprints with conversely, only Cuba is approaching the green sustainability square, managing to reflect a sustainable position, but with a social order hard to endorse.

Figure 3: Balancing Environmental, Economic and Social parts

The responsibility to ensure sustainable outcomes and “without compromising the ability of future generations to meet their own needs” will require very robust review of the balance environmental, economic and social parts. Figure 3 shows the small central overlap required for sustainable balance.



2.3 Limits to change: mobility of people & goods

Considering the world balance and demands and the societal values of Australia, the scope or limits to change the sustainability of mobility of people or goods is constrained. Moving from high individual freedoms and wealth will require changes of values with improved and cost effective alternatives in major changes in demand are to occur. These could be promoted through taxes and legislation hastening change such as increased fuel taxes, greenhouse gas levies or carbon pricing.

From a “use of” roads perspective the modal shift from cars to public transport is possible within the city or urban context, but the cross subsidies on urban public transport have to be considered in the sustainability argument. For rural communities both people and goods mobility will continue to require roads although the vehicle types and energy sources can be expected to improve.

Overall there is least flexibility on goods transport as it is non-discretionary and reflects the viability of the consumptive and commercial viability of a society. Goods transport also places the greatest demand on road pavements.

That leaves the drive for road usage and provision sustainability and the concepts to address to:

1. Improving the quality of the mobility experience

2. Keeping the use of scarce resources within their carrying capacity

3. Looking for improvements in the performance of current systems

4. Seeking more sustainable, cost effective solutions.

2.4 Infrastructure Sustainability Assessment

There are numbers of rating systems around the world attempting to evaluate options to best promote best sustainable infrastructure solutions.

Figure 4: AGIC Infrastructure Sustainability Assessment Categories

In Australia the State Road Authorities (Victoria, NSW) have considered the development of a standardized system for roads infrastructure and works has also been undertaken by the ARRB. Another system is being developed locally from ground up by the Australian



Green Infrastructure Council (AGIC) which has a wide range of support in the road authority, construction and consultant sector.

The categories adopted for project review are detailed in Figure 4 and provide a “big picture” view of sustainability assessment. Also of use are the definitions in the categories which further explain the intention underpinning the sustainability message. For example, Category 3. Using Resources provides has the Objective: “To minimise consumption of precious resources and optimise resource efficiency through lifecycle/cradle-to-grave thinking. To move towards a world where natural resources are consumed no faster than the planet can replenish them.” With the explanation or intent further defined as: “Resources include non-renewable extractive materials from mines and quarries, old growth forest timber and processed metals. There are processes involved in obtaining, processing and transporting these materials that use energy, create pollution and generate waste. Some materials are also scarce and may not be renewable, so it is important to avoid or minimise the consumption of these or substitute with other materials. The intent of this category is to encourage the adoption of “Design For Life”/”Eco-Design” approach and consider opportunities to preserve or enhance “Natural Capital” as an alternative to options which deplete non-renewable resources.

And lastly the specific aspect of selection and use of materials in Category 3: “We need to reduce the use of “new” materials. Residual needs should be satisfied by reuse and recycled materials. Materials used should have durability appropriate to the asset lifecycle (ie fit for purpose), minimal inbuilt redundancy/failure and have minimal short or long-term impacts on the environment. Maintenance issues and demolition/disposal and recyclability are an important consideration for the life of the project. Materials selection should consider environmental aspects throughout the material lifecycle including energy aspects (ie embodied energy).”

Subsequent chapters in these notes will cover the aspects raised in this proposed rating system when considering bituminous surfaced roads and asphalt pavements.

3 SUSTAINABLE ROAD ASSET PROVISION & MANAGEMENT

3.1 GENERAL Environmental sustainability and business sustainability are both critical to the world we all live in and an important part of any successful business. Staying in business requires sustained profitability which in a market economy, such as Australia, must integrate new or strategic changes arising from technology development and new legislation and associated regulations. Environmental sustainability requires recognising the impacts of actions. Participation in road asset provision therefore requires meeting the road agency / owner expectations as well as implementing sustainable practices. This must be done whilst promoting opportunities for innovation, cost reductions and seeking opportunities to reduce usage of scarce resources. Opportunities exist for cooperation to provide new ideas to address sustainability including opportunities to reduce CO2 emissions and reduce land fill. These must also meet or exceed future regulations. Numbers of initiatives to recycle materials and reduce energy requirements are already being rolled out. Sustainable road network provision and management requires measurement, recording



and management of the asset from a position of knowledge. This must include the costs incurred by the road user as well as the direct costs incurred by the road owning authority. Without this knowledge the assessment of road transport costs are one sided. The road user contributes 10 to 400 times the cost of operating the network and those costs must be considered in overall state funding. That knowledge should drive the minimum levels of maintenance funding to ensure the optimum performance from the asset. Underfunding should be recorded and lower levels of service declared to the road user. Methods of assessing the relative impacts of gains in efficiency and alternate product CO2 generation are included in “carbon” calculators available internationally. Flexible pavements have lower impacts on CO2 emission than those including cement & steel. Bituminous pavement is also potentially 100% recyclable eliminating land fill and further reducing greenhouse emissions. Road construction and maintenance materials have supply limitations around areas of urban development but are available with longer haul distances. Peak Oil concerns are not considered to have any significance to normal operations over the next 15 to 20 years, although the price of bitumen will track any rises in energy costs. Products & systems of delivery are available that will increase the use of waste products, recycle greater quantities of scarce resources and reduce energy and CO2 – details are included. Vegetable or plant-based bitumen substitutes are becoming available in small quantities. Due to their high production cost they are currently used only to a limited extent.

3.2 SUSTAINABILITY PRINCIPLES 3.2.1 Sustainability means 1. Protecting and supporting the environment for the community & broader society 2. Remaining profitable 3. Not running out of resources:

o Binder, aggregate, PMB, sand, filler, agents o Equipment spares, tyres o Fuels – diesel, LPG, LNG, fuel oil, electricity o Human – skills, numbers, affordability

4. Reducing waste increasing recycling 5. Maintaining an acceptable social profile & impact 6. Improving efficiency – more for less, lowering costs, less energy use, greater output,

improving product performance

3.2.2 Sustainability is good business practice Better profitability in a competitive market economy will pivot on the tenets of good sustainability practice. Lower costs, greater efficiency and improved delivery are all included in the process. Without sustaining a higher income than the expenditure or profit the industry cannot be sustainable. There are opportunities for improving the Sustainability of Road Asset Management by improving the industry’s delivery & types of road products used by the State Road Authorities. Environmentally sustainable practices also make good business sense, supporting the community and operating within relevant legislative requirements.

3.2.3 Innovation promotes sustainability Good business outcomes for the supplier mean meeting the requirements of the client at a price lower than competitors (when in a lowest bid price market). Under these conditions a barrier becomes the ability to derive better asset performance outcomes which are flexible enough to accommodate the changing world impacts on price, availability, environmental impact and changing social values.



There are two extremes to the barrier:

1. One is where the client is aware of the options and leads the charge for innovative approaches but is unable to get the industry to support the initiative. This may require the innovative company to take high risks, although this could also lead to high returns if the innovation is successful. A better approach would be for risks associated with the introduction of new solutions to be shared through incentives and protection against unexpected impacts and risks on works.

2. The other extreme is the opposite, where clients are risk averse and embedded in historical specifications locked into given and reasonably performing solutions. In this case the introduction of innovative solutions with lower cost, performance based outcomes generally have a very high transfer of risk to the contractor / supplier and the setting of high performance expectations. In some cases the client may even actively oppose innovation.

Clearly there is middle ground and systems have been developed to simplify the adoption of improved solutions for road assets – Avis Technique and HAPAS are examples.

A mind set of seeking better solutions with an understanding that the road asset owner is the beneficiary of the improvement need to underpin the development. This is embedded in the UK Strategy for Sustainable Construction June 2008 where Innovation is described as “To enhance the industry’s capacity to innovate and increase the sustainability of both the construction process and its resultant assets.”

3.2.4 Drivers to enhance sustainability For a commercial entity in a market economy the key driver will be profitability and the ability to encourage ongoing investment in the sector. However, the construction sector is notorious for its big peaks and troughs in demand making investment in capacity & training a risky decision. Sustainability of demand is therefore a metric which establishes the benchmark and risk profile of the sector and significantly affects long term investment and participation by industry. The financial drivers also fit within the overall framework of laws and regulations with the criteria for working in a sector including zoning, environmental obligations, safety requirements, and in the case of road building and ownership, the service standard demands by the public and their representatives. In times of major change in legislation (e.g. new energy or carbon based charges or operational constraints) the effects will distort and rebalance the cost & efficiency assessments. Production processes will change; energy sources will switch which can lead to the removal of certain product types in favour of others. A lower order but commercially relevant driver is the quality and specification standards set for manufacturing and supplying the road products. This is particularly important were scarcities are created (PMB demand, production limitations, product availability) and there is limited opportunity for alternative or innovative options. 3.2.5 Road Asset Management principles “If you can’t measure it you cannot manage it” is a phrase as valid for road asset management as it is in any undertaking. Roads deteriorate over time and the pavement design philosophy is based on consumption of the asset over a defined time or usage. To assess the sustainable use of the road assets and then to manage the asset requires measurement and knowledge. There are limits to what measurement is possible. High value data includes safety (skid resistance, questionable geometrics and specific accidents) and condition of the pavements (materials used, cracking, deflections, age) all measured over time and usage.



Improved measurement technologies and reduced communications and data manipulation costs will allow for increasing measurement and better interpretation to promote improved efficiencies from the road assets. In particular improved measurement will highlight the direct link between the effective management of the road asset and the provision of adequate maintenance. 3.3 FUNDING SUSTAINABILITY 3.3.1 Funding as a sustainability requirement The concept of road pavements being consumed with usage and the need for geometric (space) growth to accommodate greater road usage impacts significantly on the efficient use of the road asset and on considerations of sustainability. The statement of a “stitch in time saves nine” is applicable to adequate maintenance of the road network. By underfunding maintenance and not providing the necessary waterproofing or structural enhancements expected in the original construction severely devalues the original investment. For example, a thinly surfaced granular pavement rapidly deteriorates when water penetrates the granular material reducing its strength by between 30 and 50%. As the traffic does not stop to allow the weaker pavements to dry out, this results in accelerated pavement failures often exceeding maintenance capability and leading to significant destruction of the road asset. The original asset goes through a rapid and unnecessary reduction in value, loss of service to the road user and presents a difficult and expensive situation for the Asset Manager to solve. If funds are not provided to protect and maintain the roads asset it is left to Asset Managers to gamble with what funds are available in an attempt to outguess weather and climate conditions until such time as the road completely fails and requires major reconstruction. This is not a good use of tax payer’s investments and poor as a sustainable outcome. 3.3.2 Mobility – moving vehicles on roads compared to water in pipes If the road network was compared to a water supply network it becomes easier to understand the shortcomings of current approaches to the maintenance of roads. It may be argued that this is largely driven by the lack of control on the usage of the road network and the poor understanding of the performance of the network pavements under variable loading conditions. From a road perspective the environmental extremes of weather also have a major impact on service delivery. However, these factors can be taken into account in a properly managed road construction and maintenance approach.



The water supply network is one where there are a number of suppliers of the necessary infrastructure including water collection and storage facilities, major distribution and treatment facilities leading to bulk and household specific distribution of the service – water out of a tap or into an industrial process. The quality and quantity of supply is the responsibility of the water authority and the user pays by metered consumption and this may even be limited in consumption to match supply constraints. This relationship is one of a paid supply with potential to limit over consumption. It is worth noting that there is acceptance of a “minimum consumption” level for the service which is required to maintain the “health” of the user. The water authority measures its storage and measures its supply. It has a network of multiple redundancies which allows for re-routing supply to match maintenance and demand. Further, it has a steady stream of income, linked to consumption and would be expected to measure usage overtime and provide increased capacity in advance of demand. For a water authority, the service delivery costs are reduced by improving the efficiency of the network and recognising that any major failures have an immediate “commercial” consequence. For water supply the concept of “user pays” is easy to understand and offers a comparison to the very different road “mobility” supply model. Roads deliver mobility to the user and importantly they carry the freight that underpins, sustains and grows the community. As for water, there is an expectation that there will be a minimum level of mobility & freight haulage allowing for healthy living. So if a community is cut off by floods there is little option but to fly in support which is born as a social cost to the broader community. Roads can be considered to therefore meet two clear needs:

1. One is the social support of communities and people. This is mimicked in the 70% passenger transport subsidies to rail, bus and ferry where the contribution for mobility is supported from taxes.

2. The other is support for commercial activities, mostly road freight but also commercial mobility and the generation of taxes through business activities. The investment in roads for this purpose is reflected in efficiencies and in the economy of the State with direct linkage to State Domestic Product and to overall National GDP.

Based on the above there will always be two major reasons for road funding, social and commercial. Collectively roads support our whole economy and social structure, our whole way of life. 3.3.3 Sustainability and road funding levels While social mobility & sustenance are discretionary calls on the general tax base, the commercial component must be funded as a business sustainability right and to support the economy through the commercial advantages brought by the use of the road. What sustainability in road asset funding should ensure is the provision of the minimum roads budget that sustains the network to the committed level of service. If that funding level cannot be



met, then the network should be decreased in size or the level of service reduced in consultation with the road user. Clearly, any decrease in network size or service standard transfers the costs to the road use and hence the State’s economy. This then places ongoing costs on the state’s or national economy. If the road network is allowed to continue to deteriorate, it will eventually be unable to meet community and business needs. Measurement, linked to justifiable performance outcomes, should be used to assess the quantum of funds required to maintain the network. The expenditure to achieve that standard should also ensure the overall backlog of required network maintenance is met. The table above plots the budget allocation by Queensland Transport and Main Roads since 2001 showing an increasing quantity directed to maintenance and rehabilitation but at a low percentage of the overall asset value. This, at a time when road demands are increasing, reflects a significant increasing backlog in required maintenance. 3.4 INCLUDING ALL THE COSTS 3.4.1 Overall costs of road transport – who carries the biggest load? It becomes clear from full life-cycle cost analyses of road infrastructure investment that the cost to the road user / transport operation is far greater than that of the road authority in supplying the facility. The design and construction of a road will have an impact on the long term economic and environmental costs. For example a properly designed full depth pavement used on a major freeway or toll way will have the ability to last perpetually, with only regular maintenance on the top, wearing course. Maintenance of a wearing course requires milling the top surface and replacing it with a new top layer. The old wearing course can also be reused as bituminous surfaces are 100% recyclable. The initial costs of this road will therefore be quickly recovered and the environmental impacts will be significantly reduced when compared to a road that requires major rehabilitation or reconstruction. Spray sealed roads that are appropriately designed and maintained will significantly reduce both economic and environmental costs. As well as the direct economic and social costs associated with roads, there are other costs such as greenhouse gas, use of materials, land fill etc. If an assessment of sustainably, was undertaken this would further change the design, delivery and operational / maintenance imperatives of the State. There are some greenhouse emissions associated with bituminous surfacing although bitumen is not used in the construction of a road way it is not actually consumed, being able to be fully recycled. By comparison reinforced concrete pavements which have a high level of embedded greenhouse energy associate with its production and is not fully recyclable. Based on research by Colas “Energy Consumption & Greenhouse Gas Emissions” 2003



The analysis revealed that over the 30 year design life of the pavements considered, the energy and greenhouse emissions were 10 to 400 times more from the traffic than in constructing and maintaining the roads. Conclusions drawn for the French / European market were:

Any road investment model assessing the allocation of government funds should consider life-cycle-cost which by nature must include the usage costs (e.g. fuel consumption, tyre wear, vehicle damage, user time etc), not just the agency ownership costs. If efficiencies and CO2reduction are to be improved then the gradients, road smoothness and operating speeds must be included in the assessment. With road user costs and community costs such as greenhouse emissions being many times greater than the road owner costs there are very significant economic grounds for efficiency improvements for those using the road. Allowing a road surface to become rough or slippery has accident and operating cost implications. Accidents have direct impacts on the community as well as significant economic costs. Reducing speed limits to accommodate road deficiencies also carries a double penalty. Reduced speeds mean that to convey the same quantity of freight will require increased numbers of vehicles and be less efficient. Quality of life is reduced due to lost leisure time (slower speeds and longer delays due to congestion) and increased costs of transport (slower buses and cars cost more per km travelled).

So the Road Asset Sustainability ledger should not only quantify, measure, report and track the expenditure with respect to proven need over time, but it should also track the unnecessary costs transferred to the road user through delayed maintenance. Without



Smooth roads save money, promote safety and grow the economy

measurement and reporting, informed management cannot take place, road maintenance funding will not be matched to the required level of service and road asset management will remain a gamble on the life of State assets against inadequate budgets.

3.4.3 Smooth roads reduce fuel consumption

“Published data on road surface effects on fuel consumption or rolling resistance have indicated significant influences of different textures. An experiment on road macro-‐ and mega texture influence on fuel consumption has been performed by VTI in Sweden. The result of the study shows that fuel consumption for a passenger car varies over a range of approximately 11 % from the smoothest to the roughest pavement tested.

Fuel consumption on cement concrete is about the same as on dense asphalt concrete.”

“In another experiment in the Netherlands, fuel consumption for passenger cars driving at constant speed on different types of pavements was studied. The results of the experiment show that fuel consumption varies up to 7 % for different road surfaces. The results also show that there is no significant difference in fuel consumption between asphalt and cement concrete road surfaces.”

“At WesTrac, an accelerated pavement test facility in Nevada, USA, fuel consumption for the driverless trucks used for pavement loading has been studied before and after major rehabilitation of the pavements. The data showed that rehabilitation reduced average IRI, International Roughness Index, by at least 10 %. Under otherwise identical conditions, the trucks used 4.5 % less fuel/km on smooth post-‐rehabilitation pavement than on rough pre-‐rehabilitation pavement.” Reference: EAPA TC/03/N269 Environmental and Fuel Efficiency of Road Pavements



3.5 MEASURING AND MANAGING 3.5.1 Measuring “carbon” As indicated previously sustainability is just part of good business sense and the flexible pavements industry has long been committed to reducing its costs as its normal ongoing commercial driver. As a result the flexible pavement industry is continually working to reduce greenhouse and other emission. When one adds extra commercial measures to the operating cost equation it begins to change the framework of measurement and will likely result in different outcomes, often this is the goal. The proposed Emissions Trading Scheme or possible Carbon Capping approach are typical interventions to achieve a change in behaviour. Whilst not defined as yet, the clear intention is to contribute to reducing concerns on Climate Change and reduce CO2 equivalent emissions. The road construction sector, as a major server of government investment, is aware that it will be approached for savings and reductions. A consultative approach has been adopted in some countries with “The Strategy for Sustainable Construction” scheme in the UK being an example. http://www.bis.gov.uk/files/file46535.pdf Jointly government and industry developed a business case for sustainable construction based on:

Increasing profitability by using resources more efficiently; Firms securing opportunities offered by sustainable products or ways of working; Enhancing company image and profile in the market place by addressing issues

relating to Corporate and Social Responsibility.

The road surfacing industry in Australia is gearing to meet these changed expectations and currently many hot mix asphalt contractors report, under the Australian Government, Department of Resources, Energy and Tourism, Energy Efficiency Opportunities program which has been in operation since 2005. http://www.ret.gov.au/energy/efficiency/eeo/pages/default.aspx Members have contributed their experiences on changing operational techniques and through extra measuring of itemised energy consumption have resulted in reductions in energy consumption. One example is the introduction of variable speed electric fans on the exhausts of aggregate heating drums. Previously airflow reduction was achieved through a flap or damper to the air flow, which retained the motor speed and just stalled the air flow. Measureable savings were achieved. Through the Australian Government Department of Climate Change and Energy Efficiency’s National Greenhouse and Energy Reporting Act 2007 (NGER) and Regulations, AAPA members are measuring and reporting on their energy usage and continually seeking ways to reduce the consumption of energy. 3.5.2 Embodied energy in road construction The greenhouse emissions associated with road construction are principally related to the use of energy to extract, transport process and apply materials. The amount of energy used is therefore directly related to greenhouse emissions and is referred to the “embodied energy” of the material. Heating during the manufacture of hot mix asphalt HMA consumes between 400 and 250 MJ per tonne



with the range affected by size of plant, moisture of the input materials, throughput per day and general age / condition of the plant. When considering CO2-e the source of this energy can be from granulated coal, diesel, fuel oil, LNG and LPG. All are typical energy sources, each has a cost specific to a given location and each has a different carbon dioxide equivalent value. As current drivers are financial, the cheapest available source would be targeted with a standby available if there was a disruption in supply or a sudden price spike. Should legislation of regulation impose taxes or penalties on the amount of CO2 generated then the commercial consequences would be assessed and actions taken to continue to provide the most cost efficient asphalt. If a value is attached to carbon dioxide generation then the ratios of CO2 per unit of energy would need to be included in the calculation. ( LNP = 0.72, Oil = 1, and Coal = 1.3 ) 3.5.3 Road surfacing vs road usage – carbon generation Information quoted in European investigations, EAPA and Colas, shows that the construction, maintenance and operation of roads account for between 2% and 5% of the total greenhouse gas emission. By implication 95% to 98% of greenhouse gas emissions are from the use of the road. So when considering sustainability, significant reductions in energy and greenhouse gas emission are most readily achieved through providing flatter and smoother roads. A deep road cutting or major fill may appear expensive to construct but the overall savings are reduced cost of operating the network providing efficiencies and improvements to the economy. For carbon dioxide reduction the biggest road asset contributions, the low hanging fruit, comes from improving the smoothness of the network and to reducing the road gradients in high traffic areas. 3.5.5 Carbon Footprint Calculators As to be expected in any commercial change, the potential to reposition one product versus another based on changed evaluation criteria, results in lots of submissions to clients identifying differences between products. In the case of AAPA there has been a preference to reach an internationally agreed common position based on independent assessment of the flexible pavement sectors products. The Global Asphalt Pavement Alliance (NAPA, EAPA, AAPA, Sabita, JRCA) are shortly to release documentation on this. The NAPA “Mix Plant Greenhouse Gas Calculator: Total Facility Emissions is available at http://hotmix.org/ghgc/ghgcv3.html . In the UK a calculator has been jointly developed by TRL, Highways Agency, MPA, RBA and supported by WRAP and CSS named asPECT “asphalt Pavement Embodied Carbon Tool and is available at: www.sustainabilityofhighways.org.uk

Greenhouse and Road Construction – Issues & Opportunities AAPA Presentation to RTA 2008 (Note: 1 m3 of asphalt is approximately 2.45 tonnes. Therefore the embodied energy in 1 m3 of asphalt produces approximately 0.025 CO2-eq/m3 or about 10% of the emissions from the same quantity of

t )



This calculator is in development and requires input from local plant and materials data. Currently the calculators can provide means for evaluating the greenhouse gas or carbon dioxide equivalents but the commercial implications await the pricing of these emissions.

NAPA Mix Plant Greenhouse Gas Calculator: Total Facility Emissions

RTA greenhouse gas inventory 2000-2001 – reflects relative difference in CO2-e



3.6 SCARCITY 3.6.1 Scarcity considerations for materials It is worth noting that the supply of energy is a market driven process and supply and demand has a significant impact on what is economically usable. For example a recent asphalt plant expansion in Brisbane sought to use, as base heating fuel, LPG but due to limited supply capacity for industry was prevented from using that fuel. So using CO2-e as a measure to drive change in energy use has to ensure that the supply side of the equation is also addressed. With good planning that should be through incentives provided for capacity growth and delayed penalties for switch over. Sometimes the market mechanism needs coaxing to function well. When considering scarcity the full range of materials used by the road asset sector needs to be considered. Scarcity needs to be evaluated from the availability of alternate or substitutes and from the reliability of the supply chain. These range from:

Steel used from bridge & pavement construction through guard rails to sign posts. Wood products used to repair and construct bridges Quarry products used in concrete, road pavements, asphalt and surfacing Binders: lime, cement, bitumen, polymer modified binders & emulsions Fuels for construction – diesel, petrol, kerosene, LPG, LNG, fuel oil, granulated

coal Components – fillers, fly ash, crumb rubber, SBS, EVA, PBD, sand, gravel, adhesion Roadside furniture – noise barriers, road signage, road markings Specialist traffic – control equipment – signals to computers & systems Testing equipment & systems – field to laboratory

asPECT calculator for Asphalt Pavement Embodied Carbon



“Logistic plot” 1956 the “Hubbert Curve”

DETAIL ON SOME PRODUCTS

Availability 15 to 20 years Green Alternates

Q1 Quarry products – road base OK, limits in urban areas No – cheapest option Q2 Quarry products – concrete

stone OK, limits in urban areas No – cheapest option

Q3 Quarry products – asphalt stone

OK, limits in urban areas No – cheapest option

Q4 Quarry products – surfacings As above but high PAFV Manufactured & slag C1 Cementitious – lime Capacity limitations Imports? Fly ash C2 Cementitious – cement OK, some capacity limits Imports C3 Cementitious - fly ash Capacity & quality limits B1 Binders – bitumen OK, high import capacity Research level only, plant

based, Tars – economic, not green

B2 Binders – polymer modified Production capacity limits Crumb rubber - waste B3 Binders – bitumen emulsions Production availability &

limits No

B4 Binders – cutback bitumen OK, no known limits, JetA1 Emulsions F1 Fuels – diesel OK, imports vs limits LNG F2 Fuels – petrol OK, imports vs limits Ethanol & LPG F3 Fuels – kerosene OK, no known limits, JetA1 No F4 Fuels – LPG Limited by distribution No F5 Fuels – LNG Limited by facilities No F6 Fuels – fuel oil OK, coal dust alternate LNG, LPG

3.6.2 Peak oil – myth or message Bitumen is the main glue for the operation of the Queensland road network, being sourced from the refining of crude oil. Concerns as expressed in “Peak Oil” reserves has been aired in the press and the subject of many opinions. The view of the suppliers of crude oil is that there is a reliable supply of the product long into the future and for many generations beyond the expected peak in demand for fuels. Bitumen is a product that is produced in a specialised way. Most new refineries have the ability to convert 100% of crude oil to aviation fuel, petrol and diesel, producing no bitumen at all. Some refineries in the Asia Pacific region have been geared for high volume or even dedicated production of bitumen. These refineries produce bitumen to the Australian AS2008 standard and increasing volumes of this binder are being imported and the binder is performing well on Australian and Queensland roads. Bitumen’s price is linked to its value as a fuel which is also the case for other petroleum energy products fuel oil and diesel. The overall price of energy sources is interlinked as they can act as substitutes for one another. So the price of coal is linked to the price of oil as an energy alternate, and electricity costs rise to match the coal or petroleum input costs. Whilst hydro, wind, geothermal and solar power may add to the available pool the quantities of energy that they supply in Queensland is unlikely to hold down energy costs in the medium term. Only nuclear power has the ability to peg low bulk energy costs but, even if politically acceptable, it is unlikely to impact to any significant effect for the next 20 years. So energy costs will continue to be linked to the availability of coal and crude oil both will rise in a market economy as demand increases to a level which matches alternate



supplies from alternate renewable sources of energey. Bitumen prices will match that rise and with few binder substitutes likely to be available in sufficient quantities it will continue to be in demand. Australian sources of crude oil used for making bitumen include Saudi Arabian crudes which is from the largest crude stock pile in the world and should continue to be available far into the future. Increasing bitumen prices will encourage enhancing the binder properties through polymer modification and durability improvements. Agriculturally derived vegetable or plant based binders are available, but as for ethanol included in petrol, the displacement of food production to generate petroleum substitutes is unpopular and only relatively small quantities are available. If sufficient volumes of plant or vegetable sourced binders become available then there may be the opportunity for partial inclusion or modification on normal bitumen. Peak oil as a concept is relevant but as has been seen in many past concerns about the limits to growth, mankind’s ingenuity has managed to address each of the challenges as they arise. At high prices more oil will be found and will be able to be extracted. And at very high prices substitutes will be found. For example, “Tar sands” contain large amounts of bitumen like material and simple, but high cost techniques can extract the product – Canada is already extracting commercial quantities. 3.6.3 Scarcity considerations for skills The need for smarter and more capable people in the sector with skills matched to the demands of road asset supply, management and repair will continue to be a key sustainability requirement. Skills matched to tasks and expanded to address future challenges can only be achieved through measuring the needs and managing the changes. Competition for infrastructure supply and management skills will continue to be high whilst there is growth in the State, whether through mining expansion or population growth. Boom and bust cycles impact heavily on the civil construction staffing. This is because the boom and bust is a disincentive to employment in the sector, seen to be unstable, and because of the distortion it brings between project-based pay scales and those of long term operations. Achieving a smoothed flow of funding to the road sector and advanced knowledge on planned works (maintenance & major projects) helps dampen concerns and reduces the big swings in pricing. Queensland Transport and Main Roads RIP program of 4 to 5 years of planned works ahead, along with the sharing of details of shorter term project timing is leading in this field. The benefits are tangible and result in reduced project costs of 4 to 5% to Queensland as estimated by Roads Australia. Scarcity in the skills base can be addressed through importation of skills supported with training on local knowledge and through programs to improve the image and career opportunities on offer. A smarter, up-to-date sector seen to be moving with the latest and best in technology, management systems and openness to innovation and change is a good goal to promote participation.



The SkillsDMC Sustainability Consultation Report of December 2009 has identified the need for new skills and the necessary quality resource / support materials to assist in the delivery of training. Sustaining Road Assets will need to identify the new green skills that are required to manage its assets and participate in the development of training support material. AAPA & QTMR have capabilities in this regard and are working to develop joint efforts.

More attention is also being paid to develop and identify those skills held by those people working in the industry. These are and will continue to be enhanced.

3.7 IMPROVING PERFORMANCE & SUSTAINABILITY 3.7.1 Performance improvements The industry is aware of potential performance enhancements that can assist in energy efficiencies and reduction in environmental impacts. These include:

1. Durability improvements 2. Greater functionality – skid resistance – better, thinner 3. Better pavement performance – thinner & stronger 4. Maintenance geared to requirements – cracks sealed, reseals done 5. Products matched to requirements – highly elastic binders for waterproofing 6. Waste reduction and recycling 7. Reducing energy consumption

But, without support from road asset managers the ability to benefit is limited. Examples of these improvements which are available now in Queensland follow.

3.7.2 Flexible pavement solutions available – now Perpetual pavements Conceptually the idea of not overstressing a flexing structure significantly extends its performance life, is what is addressed in the “perpetual pavements” drive in the USA. Asphalt pavement layers designed to have sufficient pavement thickness and tensile strength to prevent the initiation of cracking in

Australian Bureau of Standards – unemployment rate and participation rate reflecting the lack of skills capacity in Queensland. Mining growth and major infrastructure works will be affected.

Conceptual representation of perpetual pavement



the lowest layer results in design lives extending to in excess of 50 years. This concept could be applied to the current pavement (or even less) thicknesses being used in South East Queensland and changes the sustainability needs from structural improvement to the simple replacement of the upper wearing course layer on about a 10 to 12 year cycle to address top down cracks and reinstate skid resistance. Recycled Asphalt Pavements (RAP) In many urban areas the asphalt upper surface would be Open Graded Asphalt a noise absorbing, smooth surface which delays run off of surface water reducing the flooding impact of the road surface. And as for all bitumen bound products the Open Graded Surface is 100% recyclable and is fed back into the production of new asphalt, recovering the aggregate and reusing the bituminous binder. All bituminous bound materials removed from the road can be recycled back into hot mix asphalt production. In Queensland the amount of recycled asphalt on Transport and Main Roads works has been limited to zero. This was in contrast to asphalt used in municipal works where it is routinely included. In Brisbane City Council 100% of asphalt removed from their network is reused in the asphalt paved in wearing course and underlying layers. AAPA members have indicated that in other municipalities RAP is routinely included in the mixes used. Recent Transport and Main Roads Specification changes have permitted up to 15% on RAP in structural layers other than in the wearing course. This is an improvement but is limited in effectiveness as the layers included do not represent the high volume usage of asphalt in QTMR. The savings arising from the use of RAP are as substitute for aggregate and a proportion of the bitumen included in the RAP less the costs of acquisition and on the medium term can amount to a savings of 10 to 15% in the asphalt cost. Warm mix asphalt – change of manufacturing process for Dense Grade Asphalt In an attempt to reduce energy consumption various technologies have been applied to reduce the viscosity of bitumen at lower temperatures. To achieve adequate coating of all fine and coarse particles in asphalt the aggregate and bitumen combination is mixed at 165 to 175 C with an even higher temperature for PMBs. Warm Mix Asphalt technologies

performance of the asphalt product. This change will result in the reduction of energy consumption per tonne of asphalt and consequently the CO2-e. The recent significant investments in new asphalt production plants in SEQ has allowed for the introduction of Warm Mix Asphalt manufacturing capability and simplified inclusion of Recycled Asphalt. At present this process to produce asphalt is not being routinely accepted on QTMR projects although it is the subject of assessment on one or two projects. Warm mix asphalt has been provided with percentages of RAP in excess of 30% on the Port of Brisbane Motorway and is performing successfully. A major AAPA/Austroads validation project is currently underway in Victoria. Emulsion based primes, primer seals and seals Whilst not used extensively in Australia, bitumen emulsified with water and emulsifiers provides a temperature and heating reduction for the spreading of the binder film used for primes, primer seal and spray seals. Under normal operations sealing bitumen would be

lower the viscosity of the binder improving adhesion to the base / aggregate and providing a good coating to the seal aggregate.



Tyre stockpile awaiting conversion

providing energy savings on heating but increasing transport costs for the included water. For haulage in the 50 to 100km range from emulsion manufacturing facilities this results in appreciable savings. Use of waste materials – Crumb Rubber By nature a waste material is one that has limited use and its disposal is difficult. Motor and truck tyres have fallen into this category and their disposal presents environmental and social challenges. The bituminous product sector has the capability of including this granular crumb rubber as an elastomeric enhancer to bitumen and it is applied for road surface sealing in large quantities in Victoria and New South Wales. Its use is limited by availability and is not considered a “waste product” when used in road construction carrying a cost linked to the product that it substitutes. (SBS or PBD). Usage in Queensland is growing but specialised equipment and handling techniques need to be developed. Use of waste materials – Fly Ash As for crumbed rubber a waste product with a clear use ceases to be a waste product. Fly ash is included with asphalt as a filler (<0.075mm fraction) providing stiffening to the binder and mix. Bitumen stabilised materials Foam asphalt or similar bitumen stabilised materials provide a special solution to cemented and failing cracked pavements. The addition of a finely dispersed bitumen film into the milled road base results in a water resistant basecourse with increasing strength overtime and little or no shrinkage or thermal movement induced cracking. The current Queensland pavement stock will benefit greatly from the adoption of this technology – already proven in the State – and will provide extra levels of protection against climate change induced flooding and in the earlier reopening of roads. Protection of scarce road surfacing gravel Unsurfaced roads typically consume the wearing course gravels at a rate of 5 to 25mm per annum. Where sufficient sources of gravel exist, this conversion of natural material to airborne dust may be an economically warranted solution. However where wearing course gravel stocks are limited or the creation of dust is an unacceptable social or commercial outcome then a thin, waterproof, skid resistance and low maintenance sprayed seals becomes an option. Modified binders are lower risk to temperature rise Common practice in Victoria and New South Wales is to the extensive use modified binders for surface seals which enhance the performance and extend the life of the investment. With the climate change potential of rising temperatures the table below indicates the softening point improvements arising from the use of modified binders. Usage Name Softening Point

Range Observation

Seal grade bitumen CL170 46 - 52 Lab results Seal grade PMB low stress S0.3B 48 - 56 2 to 4 improvement Seal grade PMB high stress S4.5S 82 - 100 Seal grade Crumb Rubber S15RF 55 - 65 Asphalt grade bitumen CL320 48 - 54 Lab results Asphalt grade PMB low stress A0.6S 65 - 95 Asphalt grade PMB high stress A5S 82 - 105



By Kym Neaylon 2005

Social responsibility – low odour binders Bitumen manufacturers have additives available to reduce bitumen odours and produce bitumen with low fuming characteristics – both promote the image of asphalt production and impacts on the community.

3.7.3 Flexible pavement solutions – on the horizon Carbon Capture in bitumen production Dutch oil refineries in Rotterdam are capturing 400 000 tonnes of pure CO2 and pipe it for use in greenhouses to boost growth of vegetables and small amounts are transported to the soft drinks industry. This is only a minor way of reducing greenhouse gas emissions but shows innovation between two industries. Putting waste products to use To produce cleaner transport fuels and reduce sulphur dioxide in the atmosphere sulphur is extracted from oil and gas. This sulphur has been processed into pellets to form a bitumen modifier enhancing the durability of the bitumen. Bitumen substitutes European and local sources have been developed for limited quantities of plant-based bitumen substitutes. In the Australian case production has taken place, research results have been circulated but the product remains relatively elusive. In France significant use has been made of the Colas / Shell Vegecol a lightly coloured binder able to provide colour matching and aesthetic advantages in asphalt. Another example is a vegetable oil based oil binder was used by Shell in Norway for HMA production. The economics of production and demand for these products will be affected by carbon pricing and client interest. At this stage only very low volume capacity is possible. Energy from asphalt There are many attempts to extract energy from the emissions and movement of vehicles using the road. This includes piezo electric generation due to deflections and breaking effects. Asphalt is also a thermal sink and the heat captured from sunlight can be transferred to homes or used to reheat the road surface in areas exposed to icing. Active Asphalt Air pollution reduction is possible by using binders developed to affect emissions from vehicle exhaust emissions. Open graded asphalt, used as noise and splash reduction inhibitors provide a large surface area well placed to trap the exhaust emissions. Commercial products are currently in development.



4. SUMMARY Whole of life evaluations of the sustainability impacts of infrastructure asset investment and maintenance are fundamental to the operation of the road network as it provides quality mobility to goods and people. Into the future this will grow and the need to balance road user demand against the scarcity of materials and increasing energy costs will promote the development of new and improved ways of delivering bituminous roads.

The bituminous or flexible pavements industry is well geared to continue to provide essential products and solutions and continues to innovate with new more sustainable products, lowering energy demand whilst providing much extended performance lives.

As alternates sources of energy become available to replace crude oil products there will be a stabilisation of demand and of prices ensuring decades of bitumen for sealing or pavement construction of our current and future networks.

REFERENCES AUSTROADS (1997) – Asphalt Recycling Guide, AP-44/97

AUSTROADS (2006) – Austroads Specification Framework for Polymer Modified Binders & Multigrade Bitumens, AP-T41.

AUSTROADS (2002) – Asphalt Guide, AP-G66/02

AUSTROADS (2002) – Framework for Specifying Asphalt, AP-T18/02

AUSTROADS AP-G63/03 : Guide to the Selection of Road Surfacings (2nd ed.)

AUSTROADS AGPT05/08 : Guide to Pavement Technology - Part 5: Pavement Evaluation and Treatment Design

AUSTROADS AGPT04B/07 : Guide to Pavement Technology - Part 4B: Asphalt

AUSTROADS (1989) – APRG Technical Note 8 – Ultra Thin Asphalt Surfacings

Australian Green Infrastructure Council, Fact Sheet 2 Infrastructure Sustainability Assessment Categories, September 2009, Brisbane, Queensland

Australian Asphalt Pavement Association (1997), Implementation Guide IG1 – Open Graded Asphalt Design Guide.

Australian Asphalt Pavement Association (1997) Implementation Guide IG2 - Cold Mix Granular Materials Guide.

Australian Asphalt Pavement Association (2000) Implementation Guide IG4 – Stone Mastic Asphalt Design and Application Guide.

Australian Asphalt Pavement Association (2002) Implementation Guide IG5 – Light Duty Asphalt Pavements: Design, Specification and Construction.

Australian Asphalt Pavement Association (2002) Implementation Guide IG6 – Selection and Design of Flexible Pavements.

Australian Asphalt Pavement Association (2003) Implementation Guide IG7 – Comparison of Pavement Alternatives.



Australian Asphalt Pavement Association (2010) Greenhouse Effect on Road Construction, Presentation by John Lambert, Kew, Victoria, Australia.

Asphalt Pavement Alliance, IM-40 Perpetual Pavements – A Synthesis, Dave Newcomb, Richard Willis, David Timm, March 2010, USA

Asphalt Pavement Alliance, IM-52 Cleaner water with asphalt pavements, 2011, Lanham, MD, USA

Asphalt Pavement Alliance, IM-46 Carbon Footprint, How does asphalt stack up?, September 2010, Lanham, MD, USA

National Asphalt Pavement Association, Black and Green, Sustainable Asphalt, Now and Tomorrow, Special Report 200, September 2009, Maryland, USA

National Asphalt Pavement Association, Asphalt Pavements and the LEED Green Building System, July 2008, Maryland, USA

AAPA/Austroads Pavement Work Tips

No. 6 Polymer modified binders

No. 7 Treatment of bleeding or flushed surfaces

No. 11 Surface characteristics of bituminous surfacing

No. 18 Sprayed sealing – Selection of initial treatments

No. 19 Sprayed sealing – Selecting aggregate size

No. 25 Geotextile reinforced seals

No. 32 Sprayed seals – A brief description

BSPP 2013Q sec18a sustainability concepts v2011 · 2016-04-12 · Sustainability Concepts...

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Transcript of BSPP 2013Q sec18a sustainability concepts v2011 · 2016-04-12 · Sustainability Concepts...