Journal: IOP Conference Series: Earth and Environmental Science

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IOP Publishing

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1755-1315
1755-1307

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Publications 1 - 10 of 52
  • Supply chain mapping and stakeholders' assessment towards the sustainable development goals: The case of the construction sector in the informal settlement of Mathare, Nairobi
    Item type: Conference Paper
    Celentano, Giulia; Salcedo Villanueva, Jesús; Habert, Guillaume (2020)
    IOP Conference Series: Earth and Environmental Science
    The UN Sustainable Development Goals are the blueprint to achieve a more sustainable future for all. One of these targets to be tackled by their implementation is the improvement of the livelihood of 1/6 of the global population, housed in unsafe informal settlements. This paper explores the correlation between GOAL11 – Sustainable cities for all - and other aspects of the societies relevant for the achievement of the SDGs –Responsible consumption and production, No poverty, Gender inclusion, Decent work and economic growth- in a mutual and potentially virtuous relationship. The work is based on months of fieldwork conducted in 2018 in the informal settlement of Mathare and in the city of Nairobi, through observation and semi-structured interviews, with the objective of understanding the current productive and economic flows of the construction sector supplying the informal city. From the study, the following statement emerged: a) different final building users (clients) operating in Mathare have access to different building materials b) the diffusion of materials inside the settlement is strictly related to the access to the shop and to the potential client sites c) the diffusion of materials inside the settlement is highly impacted by the availability of space both by the supplier store and on the building site d) tribal division plays a significant role in the distribution of roles in the construction sector. The study shows the relevance of applying a metabolic approach to the city throughout its supply chain in order to understand its ongoing logic prior to a construction intervention. This allows to understand ongoing construction practices, identify gaps and bottlenecks and propose improvement solutions fitting with the ongoing dynamics. The local economy would benefit from such an approach, tailored on its needs and potentials.
  • Innovative Binders for the Chemo-Mechanical Treatment of Dredged Sediments
    Item type: Conference Paper
    Petti, R.; Plötze, Michael; Puzrin, Alexander; et al. (2025)
    IOP Conference Series: Earth and Environmental Science ~ TC 105 International Symposium 23/09/2024 - 27/09/2024 Grenoble, France
    The article reports results from an experimental study on the chemo-mechanical treatment of dredged marine sediments making use of sustainable and original solutions. Specifically, the research entails the use of seashells and biochar as additives for the chemo-mechanical improvement of dredged fine-grained sediments that were artificially polluted by kerosene. The study includes unconfined compression tests, chemical analyses, and SEM photographs of various sediment-based mixtures. Evidence is provided that seashells represent a viable alternative to cement, as they were found to be as effective as cement when partially replacing it. When the sediment is polluted, the overall strength of the mixture reduces but shell powder is still a viable solution, both for its mechanical and chemical efficacy. The addition of biochar is more effective when just cement is used for treatments.
  • Accessing Hidden Material Flows in the Swiss Built Environment: A Parametric Predictive Model for Building Systems’ Components Reuse Estimation
    Item type: Conference Paper
    Xiong, Shuyan; Zea Escamilla, Edwin; Habert, Guillaume (2024)
    IOP Conference Series: Earth and Environmental Science
    The global construction industry plays a pivotal role in resource consumption and greenhouse gas emissions, emphasizing the urgent need for sustainable development practices. Despite this urgency, a major challenge lies in the lack of effective resource utilization models that are consistent with the principles of a circular economy. This gap hampers progress towards sustainable resource management, especially given the trend towards urbanization and growing material needs. To address this challenge, our study introduces a Parametric Prediction Model (PPM) designed to improve resource utilization efficiency with a special focus on building systems materials, which are often neglected in previous studies. The model employs a building-by-building approach to accurately assess material inventories within the building system using local databases, thereby increasing the granularity of system composition data. By utilizing state-of-the-art machine learning algorithms, i.e. linear regression and neural network, the model can handle both categorical and non-categorical data. To illustrate the effectiveness of the model, we show a sample material flow analysis schematic using a typical radiator assessment as an example. The schematic provides predictive and concise information about material flow at aggregated level as well as individual details such as location and timing at local level. The resulting output - a refined and comprehensive database - contributes to more informed decision making in sustainable resource recovery and allocation. In addition, this contribution is aligned with broader goals, including waste minimization and resource efficiency in the built environment.
  • Comparison of 16 national methods in the life cycle assessment of carbon storage in wood products in a reference building
    Item type: Conference Paper
    Ouellet-Plamondon, Claudiane M.; Balouktsi, Maria; Delem, Laetitia; et al. (2024)
    IOP Conference Series: Earth and Environmental Science
    Wood and bio-based construction products are perceived as a way to use renewable resources, to save energy and to mitigate greenhouse gas (GHG)-emissions during production and to store carbon during the entire service life of the building. This article compares the carbon footprint per kilogram of wood products (softwood beams, plywood, oriented strand board panel, and fibre board) from the perspective of the life cycle assessment methodology for greenhouse gas (GHG) emissions of practitioners from 16 countries participating in the IEA Annex 72. These materials are used in PAL6 softwood structure multi-residential building. This article aims at comparing the carbon footprint accounting methods from 16 countries for PAL6 multi-residential building. Each national team applied the reference study period (RSP), life cycle modules covered, modelling rules, the geographical scope of inventory data as well as the LCA database according to its specific national method. The results show that there are three types of methodology to assess a building with biogenic content (0/0, -1/+1, -1/+1*). The results were more variable plywood, oriented strand board, and fibreboard than the softwood beams due to the variability in the wood transformation processes among the countries. A net negative carbon balance was obtained for the softwood beam for the countries using -1/+1* with a clear assumption of the fraction of the carbon permanently stored at the end-of-life (EoL). The carbon storage is only possible if it is secured at the EoL. Participating countries apply different definitions of permanence and EoL scenarios. Guideline on assessing, monitoring, and legally reporting carbon storage at the EoL are needed, based on concertation between standard, life cycle assessment, wood industry, and climate experts.
  • New vernacular construction: Environmental awareness and territorial inclusivity
    Item type: Conference Paper
    Bocco Guarneri, Andrea; Habert, Guillaume (2024)
    IOP Conference Series: Earth and Environmental Science
    Studies on vernacular architecture document the built heritage; discuss its preservation; and sometimes focus on its sustainability, expressing admiration for the wisdom it embodies. Traditional buildings are exemplary in terms of embodied environmental impact, but can hardly be transformed into 'sustainable' buildings in the contemporary sense, for legal, cost, technical, or cultural reasons. Today's lifestyles and expectations of comfort are very different from the original ones. Much appreciation of vernacular buildings derives from an aestheticising approach that emphasises appearance and craftsmanship. Such appreciation is tied to the perpetuation of 'traditional' forms but can lead to gentrify heritage and to design buildings that are unaffordable to local individuals and communities. We present not a literature review, but a theoretical proposal of a new vernacular, rooted in locality (origin of materials, socio-economic system, skills, etc., drawing inspiration from food self-sufficiency policies) and affordable by everyone – as it was the case with 'traditional' vernacular – but also able to respond to contemporary priorities such as counteracting climate change by opting for negative-embodied carbon materials, and meeting present expectations of comfort. Each of these criteria is discussed in detail. Within such constraints, we claim there would still much scope for creativity and innovation in terms of architectural design, behavioural choices, and policy adoption. The analysis of four recent buildings designed by outstanding contemporary architects in three continents completes the paper, substantiating very different examples in tune with the proposed approach. Open questions – including regarding the possibility of future identification of quantitative thresholds to describe 'new vernacular' buildings – are discussed in the conclusion.
  • Analysis of hydro-abrasive erosion and efficiency changes measured on the coated Pelton turbines of HPP Fieschertal
    Item type: Conference Paper
    Abgottspon, André; von Burg, Martin; Staubli, Thomas; et al. (2021)
    IOP Conference Series: Earth and Environmental Science
    Geometrical changes and material loss of Pelton turbine runners as well as changes in turbine efficiency have been measured at HPP Fieschertal in Valais, Switzerland since 2012. The HPP is equipped with two horizontal axis Pelton units, with each 32 MW nominal power, 7.5 m3/s design discharge, 515 m head and two injectors. The nozzles and the buckets are hard-coated. Due to the relatively high hydro-abrasive erosion during the summer (sediment transport season), the splitters and cut-outs of the runner buckets are grinded and re-coated on-site usually every winter. Turbine erosion was quantified based on repeated measurements on two runner buckets using 3d-scanning and a coating thickness meter. The detailed geometrical models showed amongst others that the splitter width distributions are similar for buckets of one runner, but differ considerably between runners. Changes in turbine efficiency were measured by the sliding needle procedure and continuously monitored based on operating data. From the efficiency monitoring over eight years of both turbines, efficiency differences were evaluated for each sediment season and for various refurbishment or replacement actions. The mean efficiency reduction was 0.4 % per sediment season. The on-site refurbishment works partly compensate the efficiency reductions due to erosion, leading to an efficiency drop of e.g. 2 % over six years, after which the runners are usually overhauled in the factory.
  • Numerical modelling of blast-induced crack propagation in pre-fractured rock
    Item type: Conference Paper
    Liu, Huandui; Wang, Guibin; Lei, Qinghua; et al. (2021)
    IOP Conference Series: Earth and Environmental Science
    This paper presents a series of numerical simulations to investigate blast-induced crack propagation in rock specimens embedded with a pre-existing fracture. The simulation is conducted using the particle-based discrete element method, which can effectively capture many important geomechanical processes such as solid vibration, crack growth and fracture sliding. Particles are assembled based on the grain size distribution of Beishan granite using a Voronoi tessellation algorithm, with the parameters of particle contacts calibrated against to the laboratory testing results. The pre-existing fracture is represented using the model of smooth-joint contacts. In this study, three sets of models are established to explore the effects of stress state, fracture length and fracture orientation on the damage evolution in the rock specimen subject to a blast load. In the first set of models, we observe that when the horizontal stress σx is not equal to the vertical stress σy, the maximum slip of the pre-existing fracture is positively correlated with the differential stress, i.e. Δσ= σx − σy, which further leads to the generation of different numbers of secondary cracks. The second set of models shows that the number of secondary fractures grows as a quadratic power function with the increased length of the pre-existing fracture. Furthermore, extensive tensile stress regions emerge around the tips of secondary fractures. The third set of models focuses on the sensitivity analysis of fracture orientation, showing that with the clockwise rotation of the pre-existing fracture from the vertical direction, the number of secondary fractures decreases significantly but they are still concentrated locally at the tips of the pre-existing fracture. The research findings of our paper have important implications for the assessment of excavation damaged zone properties around nuclear waste repositories built using the drilling and blasting method.
  • Modeling farmers' adaptation to climate change
    Item type: Other Conference Item
    Finger, Robert (2009)
    IOP Conference Series: Earth and Environmental Science
  • Methanogenic potential of, and C-Isotope fractionation by, diets based on C3 and C4 plants in dairy cattle and their slurry
    Item type: Other Conference Item
    Klevenhusen, Fenja; Bernasconi, Stefano M.; Kreuzer, M.; et al. (2009)
    IOP Conference Series: Earth and Environmental Science
  • When low strength materials meet funicular structures: A sustainable clay floor structure solution for emerging contexts
    Item type: Conference Paper
    Calvo Barentin, Cristián; Zornatzis, Ioannis-Athanasios; Landrou, Gnanli; et al. (2020)
    IOP Conference Series: Earth and Environmental Science
    The inevitable expansion of the built environment due to the rapid growth of the urban population in emerging contexts poses a great challenge for the sustainable development of local communities. This problem could be faced by providing adequate multistorey building solutions while using sustainable and eco-friendly materials, preferably from renewable or upcycled and locally available sources. These materials tend to have lower mechanical properties than those commonly used in conventional structures and therefore not adequate for elements subjected to bending such as floor slabs. This challenge can be met by improving the strength of the locally available materials and/or using geometries specifically designed to lower the structural stresses such as funicular structures. In this study, a novel clay-based cementless material is used. Different mixtures and additives were tested to achieve similar processing advantages as concrete. A parabolic arched floor element is designed based on a parametric analysis using graphic statics to reduce structural stresses and weight. The fabrication system is based on reusable formworks in which locally available earth is used as part of the mould. A four meters span arched floor is built to analyse its structural behaviour and to evaluate the proposed fabrication method.
Publications 1 - 10 of 52