Life Cycle Assessment of low temperature asphalt mixtures for road pavement surfaces: a comparative analysis. Resources, Conservation and Recycling, Elsevier, 2018, pp.

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This paper proposes a methodology to optimize the longitudinal profile of roads according to either an energy consumption or Global Warming Potential (GWP) criterion calculated for both construction and operation phases. For the construction phase assessment, this methodology is based on a earthworks model that computes the geometric differences between the natural terrain and the longitudinal road profile and moreover uses environmental data validated with real experiments. The operation phase is assessed by simulating traffic over a ten-years period. Traffic simulations are based on vehicle dynamic models, also validated with real experiments. The optimization problem is set up in a finite dimensional optimization. A case study illustrates this methodology. By taking into account actual traffic measurements, the optimized profile decreases by 6 % the total primary energy consumption and by 8 % the GWP.

This study presents the contributions of materials, earth engineering machines and construction techniques to potential environmental impacts from the main items of typical road earthworks. To achieve this goal, the overall activity at a 1.9-km long French earthworks project site for a heavily trafficked highway was surveyed during its 2007–2009 construction period. Using data collected and a numerical model of road life cycle assessment (LCA), i.e. ECORCE, six indicators could be evaluated, namely: energy consumption, global warming potential, acidification, eutrophication, photochemical ozone creation, and human chronic toxicity. When available, several life cycle inventories were implemented in order to appraise indicator sensitivity with respect to the considered panel of pollutants. Results also allowed estimating from an LCA point of view: (i) the conservation of both aggregates and soil as induced by quicklime treatment and (ii) the duration necessary for projected traffic levels to offset the potential environmental impacts of the earthworks stage

International audienceAbstractPurposeThis paper presents a specific tool called “ECORCE” (French acronym for ECO-comparator applied to Road Construction and Maintenance) dedicated to the road pavement life cycle assessment. This tool aims to reduce the consumption of materials, water, and energy by means of evaluating impacts.MethodsThe environmental assessment has been based on the LCA framework established by the SETAC and ISO 14040 series of standards, as well as by NFP 01010 for French products. The pavement life cycle is divided into the initial construction and maintenance operations. Several functional units can be defined in order to compare roads or road layers that have been designed to offer the same service. The system is built by selecting the processes to be considered during the impact assessment; this selection step relies on lists of main processes, such as road materials, road equipment, and material transport. The keys to building this tool were to specifically propose simple functionalities for road engineers and researchers, allow for quick case study implementation, and display a user-friendly interface. Moreover, the tool takes into account civil engineering practices and provides a set of dedicated data related to road materials, road works, and earthworks. ECORCE also allows easily changing input data (geometry, operations, materials, and transport distances); its output screens and tables offer several approaches to investigating environmental LCA results on roads.Results and discussionIt becomes possible to compare not only the materials used in a given layer but also the pavement structures composed of several layers using various mixed materials. Lastly, the tool is able to assess initial construction and maintenance policies. Various road structures and their associated traffic conditions may be examined with ECORCE. Results obtained with the tool are detailed in the paper for a highway case study aimed at demonstrating its possible uses. These results highlight that the relative magnitude of impacts from each main process can be analyzed for road design optimization.ConclusionsThe tool reveals that road pavement materials have more impact than other processes such as transport and non-road equipment running within the life cycle. The investigation of standard road practices can thus focus on various alternative materials and pavement structures, depending on the configurable functional units already implemented in the tool, as explained in this paper. The highway case study and accompanying sensitivity testing campaign serve to discuss the benefits of this tool

In accordance with the environmental concerns that national policies still address throughout the world, railways have been extensively studied to provide quantified indicators for assessing construction/operations practices. It is essential to take energy consumption, into account since energy can be measured worldwide, in addition to constituting a global environmental load that is time-limited as regards resource availability and known as a discriminating criterion in comparing transport infrastructure. This article introduces an innovative, generic and systemic method dedicated to determining the energy consumption of a railway line during the pre-project phase by taking into account the complete life cycle of the rail infrastructure, including construction, maintenance and operations. The method developed (called « PEAM ») focuses on assessing project variants during the design stage and therefore integrates both the geometric longitudinal constraints of the line and the thicknesses/volumes over the entire itinerary as design parameters for input into the various construction scenarios. PEAM combines methodologies stemming from Life Cycle Assessment with a consumption model derived from physical modeling. The models associated with this method are then applied to study the energy consumption of a new high-speed line located in France that also has major implications for the European connections currently under investigation as well. Two project variants are compared in terms of total energy for a 50-year service life and a given characteristic rail traffic, including passenger and freight flows. Results obtained reveal a 30 % difference between the two variants, which prior to applying PEAM were considered to be relatively similar.

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