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Towards greener road infrastructure Life cycle assessment of case studies and recommendations for impact reductions and planning of road infrastructure

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Abstract

The increasingly serious environmental challenges of our time call for action and it is crucial that our efforts are efficient and aimed at the main sources of environmental impacts. Also, it should be ensured that the reductions of impacts to some environmental issues do not cause unwanted increase of others. Approaches for impact reduction should therefore not look at systems (e.g. goods, services) as being separated from the economy and society, but also account for the ripple effects caused by the system in focus, and include several environmental aspects to avoid problem-shifting. This thesis addresses the environmental aspects related to road infrastructure through a range of case studies from built Norwegian road projects, aiming at identifying characteristics of their environmental performance, potential measures for impact reduction and inclusion of environmental assessments in road planning. The environmental impacts are explored through Life cycle assessment (LCA), ensuring a holistic approach which embraces the whole life cycle and a wide range of environmental issues. The impact assessment method ReCiPe was applied, including 18 impact categories. This study also involves development of LCA tools and methods for application in research as well as in practical road planning, and discussions regarding potential strategies for implementation of LCA in the road planning process. The most comprehensive case study involves two highway projects in southern Norway. One project was construction of a new highway and the other an expansion of an existing highway. These cases were chosen to render evaluation of the importance of the variation in complexity and site characteristics of the constructions. It was found that the environmental impacts related to these case studies differ quite substantially, when compared on the basis of 1 m2 of effective surface area. The main aspects causing the variations are the shares of bridges, tunnels and open road sections within each road case, and different amounts of construction activities. For climate change, the expansion highway case gives about 60% of the impacts compared to the new highway, mainly due to differences in consumption of materials such as concrete, reinforcing and blasting in construction. For some categories the expanded highway causes only 40% of the impacts caused by the new highway. For both cases, the material production and operation and maintenance are the most important stages of the life cycle for most impact categories; material production contributing to slightly more impacts than operation and maintenance. However, blasting and mass transport related to tunnel construction contribute substantially. The overall most important impact parameters, considering all impact categories, are concrete, reinforcing, steel, blasting and asphalt in maintenance. This work also includes LCAs of 52 separate road elements (9 road sections, 10 tunnels and 33 bridges), which vary in size and design and are compared on the basis of 1 m2 of effective surface area. In most cases the road sections cause the lowest impacts and bridges most. There are, however, variations here as some of the road sections are more emission intensive than some of the cases in the other elements categories. For road sections the asphalt consumption, especially in maintenance, cause significant impacts to the majority of the impact categories; in many cases more than half of the totals. Other important parameters are blasting, masstransport and steel guardrails. For tunnels, concrete and reinforcing cause high shares of the overall impacts in several impact categories, and blasting cause 70 to 80% of the totals to some categories. Ventilation and lighting in the use phase are also important factors, accounting for 15 to 20% in more than half of the impact categories. Bridges are addressed separately according to what is the main material in the load-bearing system. For concrete bridges, concrete and reinforcing dominate the impacts even more than in the case of tunnels. Overall, reinforcing contributes between about 25 and 70% of the impacts and concrete causes about 30 to 50%. Other material inputs causing significant impacts are steel, asphalt (mainly in maintenance) and electricity for lighting during operation. Steel contributes the main share of the impacts in almost all categories for steel bridges, from about 40 to 90%. Concrete inputs also contribute significantly, from 20 to 40%, in the majority of categories. Other important parameters are electricity consumption for lighting and asphalt. For timber bridges, steel is the input parameter contributing the most to impacts in most categories, followed by concrete and laminated wood. Copper is also causing significant impacts to many of the categories. ReCiPe endpoint and normalised scores are calculated for the case studies. The results indicate that for road infrastructure, the most important environmental impact categories are human toxicity, particulate matter formation, fossil depletion and climate change. The second most important categories are agricultural land occupation, natural land transformation and metal depletion. This differs from what is found in previous literature and the Product Category Rule for road infrastructure. This work has contributed to the development of four LCA tools for road infrastructure; a) the SimaPro model developed for this study, b) BridgeLCA, c) the LCA module in EFFEKT, and d) the Process code LCA model. The SimaPro model on road infrastructure is fully developed by the author, for this particular research study. BridgeLCA is developed, with significant contributions from the author, as part of a joint Nordic research project (ETSI). This tool is meant for use in planning and design of road bridges in the Nordic countries. The LCA module in EFFEKT is developed by the author in collaboration with the Norwegian National Public Road Administration, for integration in the cost-benefit analysis that is part of the planning process of road infrastructure. Three bridges (steel, concrete and timber) are analysed with BridgeLCA and three alternatives for crossing of a fjord are assessed in EFFEKT. Through supervising of a master student, a first version of the Process code method is developed, for research purposes and for investigating whether such a method could be suitable for integration in road planning procedures. It is in the early planning stages of a road project one has the largest potentials for reducing environmental impacts, as it is here the big decisions are made, such as choosing the alignment of one new road corridor among several alternative ones. Hence, it is highly beneficial to have good methods for evaluating life cycle environmental impacts at early stages of planning. The LCA module included in the EFFEKT software is considered a good starting point for this, but this study shows that the method is too coarse to be able to provide the needed accuracy in LCA results, when compared to the use of more detailed methods. The challenge at early stages of road planning, however, is a lack of good estimates for the consumption of materials and energy and the amount of different activities in the construction and operation stage, hence such information is often limited and must be deducted from merely geometrical parameters of the road infrastructure. The inclusion of LCA in later planning stages, with a satisfactory level of accuracy, is a lot easier than is the case for the early planning stage. Information from such studies at later planning stages should preferably inform also the LCA tools at early stages of planning. However, if such a tool is to be an integrated part of the planning procedures for road infrastructures, the methodology, structure, accessibility and complexity of the tool must be thoroughly considered, to ensure comparability of the quality of the assessment regardless of level of LCA experience from the user.
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... Since the early 2000s, some research has used the life cycle assessment methodology to assess the environmental performances of a road and its different stages. With different analysis periods and functional units, they examined the environmental impacts of road materials [16][17][18][19][20] and compared construction techniques and maintenance activities [10,[21][22][23][24][25] with different methods and software. Marzouk et al. [21] used the software Copert 4 [26] to assess the overall environmental impacts and primary energy associated with earthwork and pavement processes. ...
... Marzouk et al. [21] used the software Copert 4 [26] to assess the overall environmental impacts and primary energy associated with earthwork and pavement processes. Hammervold [22] applied the impact assessment method ReCiPe [27] to construction and maintenance activities of two highway projects in southern Norway in order to identify the main aspects affecting LCA results. Burdens of traffic are not considered. ...
Article
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Both the construction and use of roads have a range of environmental impacts; therefore, it is important to assess the sources of their burdens to adopt correct mitigation policies. Life cycle analysis (LCA) is a useful method to obtain demonstrable, accurate and non-misleading information for decision-making experts. The study presents a “cradle to gate with options” LCA of a provincial road during 60 year-service life. Input data derive from the bill of quantity of the project and their impacts have been evaluated according to the European standard EN 15804. The study considers the impacts of the construction and maintenance stages, lighting, and use of the vehicles on the built road. The results obtained from a SimaPro model highlight that the almost half of impacts took place during the construction stage rather than the use stage. Therefore, the adoption of environmentally friendly road planning procedures, the use of low-impact procedures in the production of materials, and the use of secondary raw materials could have the largest potential for reducing environmental impacts.
... Formal academic research on LCA and Norwegian road infrastructure has increased in the last five years. Research work has mostly been focused around the Norwegian University of Science and Technology (NTNU) but research is also being carried out at the University of Agder (UiA) and Chalmers University of Technology (CUT) Johanne Hammervold completed her PhD thesis in 2014 at NTNU and carried out life cycle assessments of more than 30 bridges, tunnels and open roads in Norway (Hammervold, 2014). Her work is the most comprehensive attempt at determining emissions in various Norwegian road infrastructures and is likely the first research in Norway to include LCA of timber bridges (Hammervold, 2010). ...
... Combining IOA with LCA gives a more complete picture of emissions where reliable process data is unavailable for carrying out a traditional LCA study, especially when price data is available. Reliable process data is especially difficult to find in the early planning phases of road construction, when the most important environmental decisions are made (Hammervold, 2014). Road projects should be using hybrid LCA when determining emissions, and the newest iteration of VegLCA will utilize more hybrid LCA data to improve decision making at NPRA. ...
Conference Paper
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Effective and efficient road transportation in Norway is a continuing concern. The growth in population and the continuing need for better infrastructure to serve this population propel the growth of road construction. Roads will continue to occupy the most prominent place in the Norwegian transport puzzle as the most commonly used form of transport by both people and goods today. The quadrennial National Transport Plan guides large scale transport planning in Norway and has recently included national CO2 emissions reductions targets for all new road infrastructure and construction. At the same time, the investment in Norwegian road infrastructure is at an all-time high, as authorities seek to modernize the Norwegian road network through megaprojects, such as the Ferry Free E39. This increase in investment and construction will inevitably lead to an increase in resource consumption and emissions without wise planning decisions, smart material choices and the use of sustainability assessment tools. Life cycle assessment (LCA) is one such tool that is used to measure environmental impacts of infrastructure and construction processes, including climate change emissions. To what extent LCA is already used in Norwegian road planning and what lessons can be learned from earlier studies that can apply to today's megaprojects are of interest to road builders if emissions reduction goals are to be taken seriously. The purpose of this paper is to determine the state-of-the-art of Norwegian road LCA and determine in which direction Norwegian research should move. The first section of the paper looks at the overarching conditions for Norwegian road construction in terms of planning, trends, and policy; the second section looks at relevant LCA studies on Norwegian roads, while the third section looks at possible research paths which should be followed to better assess and reduce the impacts of emissions in road infrastructure.
... And so far, different LCA studies have been conducted in the area of road infrastructure in order to better understand the environmental impacts associated with roads and road products such as ECORCE2, DuboCalc, PaLATE, SEVE, etc. (Zukowska E. A. et al., 2014). In spite of availability of different road LCA software tools (Hammervold, 2014), different areas of coverage could be found in the domain of software that might be due to various system boundaries and intended applications. This leads to the fact that some LCA software tools may show unexpected results. ...
... EFFEKT is a software program that is developed by the Norwegian Public Road Administration (NPRA) (Hammervold, 2014). It is a tool that assesses cost-benefit and socio-economic analyses of road infrastructures. ...
Conference Paper
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Various software tools have been developed to evaluate the life cycle performances of roads to provide decision supports for road authorities and contractors. It is therefore important to compare the strengths and limitations of these software tools to understand the appropriate application and to identify the points for optimization. This study evaluated EFFEKT 6.6, EKA, and LICCER software tools, by applying the environmental life cycle assessment following the ISO 14040 standard. The assessment was based on an open-air road (excluding tunnels and bridges) with a functional unit of one kilometer and greenhouse gas emissions as well as embodied energy indicators were evaluated in the considered software tools. The open-air road was modeled for each software tool with respects to road class H9 characteristic in Norway, classed as a national road. The assessment showed that the system boundary and purpose of use differed between the considered software tools. This resulted in performing the assessment only over A1 – 4 and B6 modules according to EN 15978 standard for the hypothetical open-air road to provide a comparable boundary condition. The results demonstrated that EFFEKT overall yielded higher values for greenhouse gas emissions and embodied energy compared to the two other software tools, while, the three software tools quantified nearly the same amount of asphalt use within the 20-year analysis period.
... MIBA can replace some of these virgin materials. Considering the entire life cycle of a road, different studies indicate that the production of the construction material and its transportation constitutes the most important life cycle stage in terms of environmental impacts (Hammervold, 2014;Mroueh et al., 2001;Trunzo et al., 2019). The use of secondary materials yields overall better environmental results in terms of the climate impact and other impact categories and is therefore recommended as a strategy to improve the environmental performance of roads (Hertwich et al., 2019;Moretti et al., 2018;Simion et al., 2013). ...
Thesis
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The low-carbon benefits and emissions savings from circular economy (CE) strategies are not yet well understood, yet are crucial for global development within Planetary Boundaries. Using the mineral fraction of waste incinerator bottom ash (MIBA) as construction material in road construction is one application of a CE strategy that could lead to environmental gains by substituting energy-intensive primary material and avoiding its alternative disposal in a landfill. The aim of this thesis is to improve the current understanding of, as well as quantify the resource efficiency and greenhouse gas (GHG) mitigation potential, from using MIBA as construction material, compared to virgin material. It contributes knowledge to local decision-making and to developing the CE concept more broadly. A Life Cycle Assessment (LCA) model to assess the environmental performance of a road built with MIBA, compared to a road built with virgin material, was developed and applied to a case study in Malmö, Sweden. Resource efficiency and GHG mitigation potential were assessed using a combination of two life cycle impact assessment methods: ILCD 2011 Midpoint+ and Cumulative Energy Demand. The results indicate less potential environmental impacts for the road scenario with MIBA in almost all impact categories. The analysis of the results shows that there can be some application contexts where using MIBA in lieu of primary material, creates larger benefits than in others. Important parameters were identified to be critical determinants for the environmental performance of the road with secondary material, including the transportation distance of materials, the types of substituted material, and specific properties of the secondary material. While the results are meant to support decision making, inherent limitations to the LCA methodology, must be considered when making decisions based on these results alone. Further research is needed to better account for resource-related impacts in a local context and to explore the effect of carbonation on the potential climate benefits of using MIBA.
... The greatest opportunity to influence life cycle impacts of transport occurs in early planning stages (Hammervold, 2014;Karlsson et al., 2017;O'Born et al., 2016), such as choice of road corridor and construction type. The choice of road corridor influences route length and construction type and has thereby a large influence on environmental impacts from future traffic on the road and on impacts from road construction, operation, and maintenance. ...
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... Construction of infrastructure, and especially road infrastructure, is estimated to be a significant contributor to global GHG emissions [2]. As a road is designed and built, the most important decisions are made in the early design phase, which can have significant impacts on the overall GHG emissions of a project [3], [4]. The use of tools, such as life cycle assessment (LCA), can help determine environmental impacts in the early design phase, but use of such tools are often hindered due to lack of data, poor interface between road designs and LCA tools, and poor understanding of LCA as methodology [5]. ...
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Building information modelling (BIM) software is increasingly being used in as a visual road design tool and offers real-time information on material demands as designs change. Life cycle assessment (LCA) is a tool that is used to measure the lifetime environmental impacts of systems, materials and processes. LCA data sets are organized according to process or product, which is ideal for implementation as a parameter in BIM. This paper seeks to explore how BIM and LCA can be used together in road design by analysing existing literature, creating a Norwegian test case on a road designed in a BIM model and adding LCA data to the model before comparing to a standard LCA study of the same road. Challenges such as including machinery emissions, uncertainty, data availability, and other insights gained will be discussed. The goal of this paper is to present a path forward for road builders to combine LCA and BIM to promote simplified LCA calculations.
... Other useful studies include Ahn et al. (2010), which looked at tunnel construction, and Capony et al (2013), which looks at earthworks in road construction. A recent comprehensive study by Hammervold (2014) examined two Norwegian highway projects, and compared all together 52 separate road element cases (9 open road sections, 10 tunnels and 33 bridges) on the basis of 1 m2 of effective surface road area, using bill-of-quantity inventory data from tender and construction accounting documents. ...
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Facing the escalating crisis of global warming, life cycle assessment (LCA) for carbon footprint has recently seen rapid development in the building and construction sector. However, the landscaping field has lagged behind the general trend within this broad sector due to the lack of applicable carbon databases. In order to overcome this obstacle, the purpose of this study is to establish a localized carbon database, L-LCC, for Taiwan's landscaping industry based on the ABRI-LCC database and according to EN15978 "cradle to handover" boundary. A critical bottleneck exists in landscaping carbon LCA, which is a dilemma between handicapping complexity in the inventory calculation of construction machinery carbon in landscaping and its mandatory requirement by EN15978. To resolve this, a carbon analysis methodology, adopting a standardized landscape component system and construction process method, is introduced in this study to incorporate construction machinery carbon into an existing component-level carbon database so as to omit complicated inventory calculations. The result shows that the L-LCC database is not on the raw material level, but rather on the higher level of hard landscaping components, e.g. roadways, paving, pond, retaining walls, etc. Such a component-based carbon database exempts users from the cumbersome compilation of raw material data and, instead, directly uses simplified component carbon data to achieve the same results. Landscape project application in carbon reduction design verified this assessment system and the calculation on carbon emissions can be done quickly. The reduction of carbon emissions is 60.3% on the comparison of the traditional and natural construction methods. Consequently, carbon hotspots may be diagnosed and carbon-cutting design may be executed more efficiently in landscaping projects in conclusions.
Thesis
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In response to increasing environmental pressure due to climate change, the global community and the Norwegian government have agreed to reduce emissions of greenhouse gases. The government-run Norwegian Public Roads Administration (NPRA) have been tasked with finding ways to drastically reduce their carbon dioxide emissions from road construction and maintenance by the year 2030. In response, NPRA has invested in research and begun the process of developing policy to promote the uptake of cleaner technologies, fuels, materials and processes. This thesis will discuss the solutions and strategies that NPRA can follow to reduce their emissions by presenting a series of articles that focus on the use of life cycle assessment models to calculate emissions of road infrastructure in the early planning phases and by discussing the implementation of emissions reductions policies. The results of this study have shown the use of models can be helpful for calculating emissions but that these models must be sufficiently robust and simple to use in order to be useful during road planning. (ISBN 978-82-7117-947-2)
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