Contribution à l'évaluation de l'impact environnemental des bâtiments (modélisation numérique des émissions dans l'eau des substances dangereuses)

Tous les produits de construction ou les ouvrages qui sont en contact avec l eau de pluie, sont susceptibles de relarguer des composants chimiques potentiellement dangereux pour la santé humaine et l environnement. Actuellement, le relargage des substances dangereuses dans l eau est évalué essentiellement par des méthodes expérimentales - généralement des essais de lixiviation réalisées à l échelle du laboratoire. Par ailleurs, les impacts environnementaux des produits de construction et des bâtiments sont évalués par l approche Analyse de Cycle de Vie (ACV), réalisées à partir de données propres aux fabricants et de données génériques existantes constituées en bases de données. Or, les émissions de polluants pendant la vie en oeuvre des produits de construction sont actuellement mal prises en compte dans ces mêmes bases de données existantes et dans les méthodes utilisées pour l évaluation des performances environnementales des produits et des bâtiments.Dans ce contexte, les objectifs de ces travaux ont été : (i) de développer une méthodologie pour l évaluation du comportement à la lixiviation de différentes matrices de produits de construction et (ii) d intégrer les données de lixiviation dans les méthodes ACV à l échelle du bâtiment. La méthodologie développée pour l évaluation du comportement à la lixiviation des produits de construction est basée sur : (1) des essais de caractérisation à la lixiviation, selon les méthodes standardisées d évaluation répondant au Règlement Produits de Construction (RPC), (2) la modélisation et la simulation des phénomènes couplés chimie-transport à l échelle laboratoire et vraie grandeur et (3) l intégration des données de lixiviation, obtenues par des simulations numériques en conditions d exposition naturelle des produits de construction, dans les méthodes ACV, aux échelles produit et bâtiment.La méthodologie proposée a été appliquée et validée sur trois produits de construction : le bois traité CBA (Cuivre - Bore - Azole), la plaque fibrociment et la membrane bitumineuse. Les comportements à la lixiviation du bois traité CBA et de la plaque fibrociment a été simulé pour des conditions naturelles d exposition à long terme, en utilisant le logiciel géochimique PHREEQC®. Les modèles chimiques développées permettent de considérer les matrices organiques et minérales et leurs interactions avec les polluants. Les phénomènes de transport des substances ont été également modélisés. Les modèles d émission développés (couplage chimie-transport) permettent de simuler la lixiviation dynamique des produits considérés, pour différentes conditions d exposition. Pour la membrane bitumineuse, seule la caractérisation expérimentale a été réalisée. Les données de lixiviation obtenues lors des simulations sur la durée de vie en oeuvre des produits ont été intégrées dans les inventaires respectifs du cycle de vie (ICV) des produits. Des méthodes d impact spécifiques ont été utilisées en association avec les inventaires enrichis pour évaluer les impacts pollution de l eau , toxicité humaine et écotoxicité des produits considérés. L ACV d une maison simplifiée a été réalisée en utilisant le logiciel ELODIE. La méthode d évaluation à l échelle bâtiment consiste à intégrer les nouvelles données construites sur la base de la méthodologie développée à l échelle produit aux autres données d ACV à l échelle bâtiment. La méthodologie développée au cours de ces travaux permet donc l intégration des données de lixiviation dans les outils ACV dédiés au bâtimentAny construction product and building undergoing contact with water during its life cycle can release chemical compounds potentially hazardous for the human health and the environment. The release of dangerous substances is presently investigated especially by experimental approaches commonly by laboratory leaching tests while the environmental impacts of construction products and buildings are evaluated by a Life Cycle Assessment (LCA) approach. The dangerous substances release during use stage of construction products (leaching behaviour) is currently very poorly represented in the existing data bases and methods for environmental assessment of construction products and buildings.In this context, the main objectives of this study were: (i) to develop a methodology for the assessment of the leaching behaviour of various construction products and (ii) to integrate the leaching data in LCA approach at building scale. The methodology developed for the assessment of the leaching behaviour of construction products is based on: (1) characterisation leaching tests at lab scale, following the horizontal standardised assessment methods for harmonised approaches relating to dangerous substances under the Construction Products Regulation (CPR), (2) modelling and simulation of coupled chemical and transport phenomena at lab and field scale, and (3) utilisation of simulated leaching data for the construction products exposed in natural condition with the LCA method for the characterization of the hazardous effect during the use stage. The proposed methodology was applied and validated on three different classical construction products i.e. CBA (Copper-Boron-Azole) treated wood, fibre-cement sheets and bitumen membranes. The leaching behaviour of CBA treated wood and fibre-cement sheets was simulated over several years under natural exposure conditions, using the geochemical software PHREEQC. The chemical models consider both the mineral and the organic matrixes and their interaction with treatmentcompounds. Mass transfer and transport phenomena were modelled. The developed coupled chemical-transport models are able to represent the dynamic leaching behaviour of the respective products in various leaching conditions. For bitumen membranes only experimental characterisation was possible. The leaching data obtained by simulation over the whole use stage of the products were integrated in the life cycle inventory (LCI) and the relevant life cycle impact assessment (LCIA) methods were applied with the enriched inventory. A simplified single-family house was modelled using a software designed to evaluate the intrinsic environmental performances of a building over its entire life cycle. ELODIE software was used in this work. The building scale assessment methodology is based on coupling the methodology developed for the product scale with the Life Cycle Assessment (LCA) at building scale. This methodology allows a proper integration of leaching data in LCA tools and answers several technical questions raised in the fieldTOULOUSE-INSA-Bib. electronique (315559905) / SudocSudocFranceF

Can decentralisation contribute to promoting rule-of-law structures? The Democratic Republic of Congo, Rwanda and Burundi as examples

Decentralisation can enable a country's population to exercise political influence at regional and local level. This presupposes a willingness to assume responsibility. It also presupposes that those in power are willing to hand over some of the power. Together these two factors can foster rule-of-law structures.   This paper describes the constitutional and administrative framework for decentralisation in DR Congo, Rwanda and Burundi. It also explores the actual situation in those countries with reference to legal literature from those countries.   In addition, it raises questions regarding the effect of instruments of international law on the decentralisation processes (international organisations, regional integration and international cooperation).     &nbsp

Caractérisation des émissions dans l\u27eau des produits de construction pendant leur vie en uvre

Les différentes actions réglementaires ou volontaires incitent de plus en plus les fabricants de produits de construction à une politique dévaluation environnementale. Une approche « horizontale » dévaluation (applicable à une ou plusieurs familles de produits utilisés dans un même type dusage) est souhaitable. Cette étude se propose de contribuer au développement dune telle approche pour évaluer les émissions dans leau des produits pendant leur vie en uvre. Les dalles en béton, les dalles en bois et les gouttières en zinc ont été désélectionnées pour létude. Les essais ont été conduits à deux échelles dexpérimentation : laboratoire et pilote (exposition à leau météorique pendant un an, avec suivi météorologique). Un modèle démission (chimie - transport) a été développé pour le cas des dalles en béton. Le logiciel PHREEQC a été adapté et utilisé. Les résultats montrent que pour évaluer les émissions dans leau des produits, dans une optique dapproche « horizontale », les étapes suivantes sont nécessaires : - la caractérisation physico-chimique du produit, qui est plus au moins complexe en fonction du produit et des connaissances déjà disponibles- la caractérisation du comportement à la lixiviation en conditions statiques et dynamiques. Lessai à renouvellement en continu (CMLT) apparaît mieux adapté pour létude de la dynamique de relargage- la modélisation du comportement des produits dans un certain scénario dexposition, qui doit tenir compte des spécificités du produit et des conditions dexposition. Les résultats obtenus en laboratoire ne sont pas directement extrapolables aux conditions naturelles dexposition mais sont essentielles pour la modélisation

Modelling inorganic biocide emission from treated wood in water

International audienceThe objective of this work is to develop a chemical model for explaining the leaching behaviour of inorganic biocides from treated wood. The standard leaching test XP CEN/TS14429 was applied to a commercial construction material made of treated Pinus sylvestris (Copper Boron Azole preservative). The experimental results were used for developing a chemical model under PHREEQC (R) (a geochemical software, with LLNL, MINTEQ data bases) by considering the released species detected in the eluates: main biocides Cu and B. other trace biocides (Cr and Zn), other elements like Ca, K. Cl, SO(4)(-2), dissolved organic matter (DOC). The model is based on chemical phenomena at liquid/solid interfaces (complexation, ion exchange and hydrolysis) and is satisfactory for the leaching behaviour representation. The simulation results confronted with the experiments confirmed the hypotheses of: (1) biocide fixation by surface complexation reactions with wood specific sites (carboxyl and phenol for Cu, Zn, Cr(III), aliphatic hydroxyl for B. ion exchange to a lesser extent) and (2) biocide mobilisation by extractives (DOC) coming from the wood. The maximum of Cu, Cr(III) and Zn fixation occurred at neutral pH (including the natural pH of wood), while B fixation was favoured at alkaline pH

Caractérisation des émissions dans l'eau des produits de construction pendant leur vie en oeuvre

Les différentes actions réglementaires ou volontaires incitent de plus en plus les fabricants de produits de construction à une politique d évaluation environnementale. Une approche horizontale d évaluation (applicable à une ou plusieurs familles de produits utilisés dans un même type d usage) est souhaitable. Cette étude se propose de contribuer au développement d une telle approche pour évaluer les émissions dans l eau des produits pendant leur vie en œuvre. Les dalles en béton, les dalles en bois et les gouttières en zinc ont été désélectionnées pour l étude. Les essais ont été conduits à deux échelles d expérimentation : laboratoire et pilote (exposition à l eau météorique pendant un an, avec suivi météorologique). Un modèle d émission (chimie - transport) a été développé pour le cas des dalles en béton. Le logiciel PHREEQC a été adapté et utilisé. Les résultats montrent que pour évaluer les émissions dans l eau des produits, dans une optique d approche horizontale , les étapes suivantes sont nécessaires : - la caractérisation physico-chimique du produit, qui est plus au moins complexe en fonction du produit et des connaissances déjà disponibles ; - la caractérisation du comportement à la lixiviation en conditions statiques et dynamiques. L essai à renouvellement en continu (CMLT) apparaît mieux adapté pour l étude de la dynamique de relargage ; - la modélisation du comportement des produits dans un certain scénario d exposition, qui doit tenir compte des spécificités du produit et des conditions d exposition. Les résultats obtenus en laboratoire ne sont pas directement extrapolables aux conditions naturelles d exposition mais sont essentielles pour la modélisation.The various French and European regulatory or voluntary actions push more and more the construction products manufacturers to an environmental assessment policy. A horizontal approach (i.e., applicable to one or several families of products used in a certain scenario) is considered the best route for the assessment. Moreover, it is required by the Mandate M/366 addressed to CEN. The aim of this research is to contribute to the development of this kind of approach, in order to assess the substances emission from construction products into water, during their service life. Three products were tested: concrete slabs, wood duckboards and zinc gutters. The experiments were carried out at two scales: laboratory scale (controlled conditions) and pilot scale (outdoor / not-controlled conditions, with meteorological monitoring). At pilot scale the products were exposed to meteoric water, during one year. A release model (chemical and transport modelling) was developed for the case of the concrete slabs. PHREEQC software was adapted and used. The main results show that in order to assess the substances emission from construction products into water, in a horizontal approach framework, the following steps are required and must take into account the product and the exposure conditions specificities: - physicochemical characterisation of the product, which could be more or less complex, depending on the product and on the knowledge already available ; - characterisation of leaching behaviour, under static (equilibrium) and dynamic conditions, which must take into account especially the use and the evolution of the product during its service life. The Continuous Monolithic Leaching Test (CMLT) seems more suitable for release dynamic assessment ; - modelling of the products behaviour in a specific exposure scenario. The laboratory data cannot be directly transferred to service conditions but they are essential for the modelling of environmental behaviour.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Biodiversity impact assessment of building's roofs based on Life Cycle Assessment methods

International audienceTo fight against the biodiversity loss and to take advantage of ecosystem services that nature can offer, urban planners integrate green spaces in urban projects. However to assess green spaces, attention is generally paid to local biodiversity (i.e. "in situ") which concerns the plot on which buildings are constructed. The biodiversity impacted outside the construction site (i.e. "ex situ") which concerns the extraction of materials, transportation and waste, is rarely associated to the project assessment. In this study, two endpoint Life Cycle Assessment (LCA) methods are applied: ReCiPe 2016 and Impact World + to assess a conventional roof and three different types of green roofs. As Life Cycle Inventory (LCI) data about urban plants are missing, we created new data to model the vegetation layer of green roofs by collecting information nearby plants nursery. This work shows that 1) extensive green roof generates the least biodiversity loss, 2) "ex situ" biodiversity is 10 times more impacted than "in situ" biodiversity, 3) the impact of the vegetation layer on the biodiversity loss is significant. LCA methods do not enable to cover all pressures threatening biodiversity and they also lack precision to assess "in situ" biodiversity. Nevertheless, their main strength is to consider "ex situ" biodiversity along the value chain of the studied systems. Coupling LCA with ecological expertise should improve the assessment by taking into account local specifi-cities and both negative and positive impacts of a system (e.g. "in situ" biodiversity gains with green roofs)

Leaching of hazardous substances from a composite construction product - An experimental and modelling approach for fibre-cement sheets

International audienceThe leaching behaviour of a commercial fibre-cement sheet (FCS) product has been investigated. A static pH dependency test and a dynamic surface leaching test have been performed at lab scale. These tests allowed the development of a chemical-transport model capable to predict the release of major and trace elements over the entire pH range, in function of time. FCS exhibits a cement-type leaching behaviour with respect to the mineral species. Potentially hazardous species are released in significant quantities when compared to their total content. These are mainly heavy metals commonly encountered in cement matrixes and boron (probably added as biocide). Organic compounds considered as global dissolved carbon are released in significant concentrations, originating probably from the partial degradation of the organic fibres. The pesticide terbutryn (probably added during the preservative treatment of the organic fibres) was systematically identified in the leachates. The simulation of an upscaled runoff scenario allowed the evaluation of the cumulative release over long periods and the distribution of the released quantities in time, in function of the local exposure conditions. After 10 years of exposure the release reaches significant fractions of the species' total content - going from 4% for Cu to near 100% for B

Modelling inorganic and organic biocide leaching from CBA-amine (Copper-Boron-Azole) treated wood based on characterisation leaching tests

Numerical simulation of the leaching behaviour of treated wood is the most pertinent and less expensive method for the prediction of biocides' release in water. Few studies based on mechanistic leaching models have been carried out so far. In this work, a coupled chemistry-mass transport model is developed for simulating the leaching behaviour of inorganic (Cu, B) and organic (Tebuconazole) biocides from CBA-amine treated wood. The model is based on experimental investigations (lab-scale leaching tests coupled with chemical and structural analysis). It considers biocides' interactions with wood solid components and with extractives (literature confirmed reactions), as well as transport mechanisms (diffusion, convection) in different compartments. Simulation results helped at identifying the main fixation mechanisms, like (i) direct complexation of Cu by wood-phenolic and -carboxylic sites (and not via monoethanolamine; complex) on lignin and hemicellulose and strong dependence on extractives' nature, (ii) pH dependent binding of tebuconazole on polarized -OH moieties on wood. The role of monoethanolamine is to provide a pore-solution pH of about 7.5, when copper solubility is found to be weakest. The capability of the developed model to simulate the chemical and transport behaviour is the main result of this study. Moreover, it proved that characterization leaching tests (pH dependency and dynamic tests), combined with appropriate analytical methods are useful experimental tools. Due to its flexibility for representing and simulating various leaching conditions, chemical-transport model developed could be used to further simulate the leaching behaviour of CBA treated wood at larger scales. (C) 2013 Elsevier B.V. All rights reserved

An Empirical Research on the Behavioral Perceptions of University Students on Their ERASMUS Mobilities Abroad

The European Union (EU) labor market needs a better-skilled workforce that can work in any of the Member States. In order to develop the skills and competencies of future competitors in this market, several student mobility programs have been set up in the EU, where they can travel to universities in partner countries to further their studies and enrich their academic performance, culture and knowledge. The best known of these programs is ERASMUS (European Region Action Scheme for the Mobility of University Students). Because Romania also participates in this program in the exchange of university students, the authors wanted, through this study, to highlight the benefits and challenges of participation in the program, to analyze how international mobilities are emotionally perceived by students and what are the behavioral reasons that determine Romanian students to choose a certain university as a study destination abroad. For this purpose, the authors conducted quantitative marketing research among students from the Transilvania University of Brasov who have been abroad with ERASMUS scholarships. The research results show that an important component in choosing a certain university is not the financial expense during the mobility as might have been expected, but rather the initial desire to study abroad. Students also consider the improvement of their academic performance as an equally important reason for embarking on mobility to the social aspect of getting to know other cultures

Influence of simplification of life cycle inventories on the accuracy of impact assessment: application to construction products

The simplification of life cycle inventories (LCIs) by reducing the number of elementary flows is a major issue regarding their use in sector-specific applications. It can ease the understanding of complete LCIs and focus on the most relevant elementary flows. Current LCIs that have been created for Environmental Product Declarations (EPDs) differ from databases provided by academics, in which more than a thousand flows are considered, as they contain a reduced list of substances. In this paper, we examine the consequences of these simplified LCIs on the accuracy of the life cycle impact assessment (LCIA) step. We consider the specific case of an LCI database for building products that was developed in France. Three environmental midpoint and endpoint indicators are analysed: the global warming potential (GWP), the photochemical ozone formation potential (POCP), and the disability-adjusted life years (DALY). The results for 110 building materials indicate that a simplification is not always relevant, as large uncertainties were detected in the final results, especially for the environmental indicators describing the photochemical ozone creation and the damage to human health that require a larger number of LCI flows. In the case of the GWP indicator, the simplification is relevant for approximately 95% of the building materials. The analysis of the key elementary flows for each indicator enables the identification of missing elementary flows in the simplified LCI. Perspectives and recommendations are provided to improve the level of details of simplified LCIs according to the impact assessment methods