Browsing by Keyword "Civil and Structural Engineering"
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Item Activating inclusive growth in railway SMEs by workplace innovation(2020-09) Carranza, Garazi; Garcia, Marta; Sanchez, Begoña; Policies for Innovation and TechnologyThe digital revolution is happening, transforming the way we move and produce. Success in the digital revolution means that the rail industries need to use the best available technologies focusing on people. The managerial and organizational practices adopted by railway entities have considerable significance for Railway's ability to succeed in global competition. One of the challenges for railway entities is to deliver innovative products, offering quickness and flexibility to respond to changing demands from their customers. Non-technological innovations and especially Workplace innovation, have a key role to play in the digitalization and acceleration of technological developments, therefore in the railway sector competitiveness. This draws attention to the importance of innovation climate and employees' commitment aiming at improving staff motivation and working conditions, thereby enhancing labor productivity, organizational performance, innovation capability, reactivity to market change, and consequently business competitiveness. As with any emerging opportunity, there is no established path to follow to activate inclusive growth in railway SMEs to uptake Workplace innovation. To address these issues, this paper develops and tests a research model that covers individual behavior, organizational practices, and process practices of innovation among employees, analyzing the impact of Workplace Innovation on firm performance.Item Analysis of life-cycle boundaries for environmental and economic assessment of building energy refurbishment projects(2017-02-01) Oregi, Xabat; Hernandez, Patxi; Hernandez, Rufino; Tecnalia Research & Innovation; PLANIFICACIÓN ENERGÉTICADespite the standardization of the life-cycle assessment methodology for the construction sector, analysts tend to apply some simplifications in relation to the system boundaries, omitting some of the life-cycle stages. In particular, for building energy refurbishment projects, there is a general focus on the operational stage, linked to the main objective of reducing operational energy use. This paper evaluates the relevance of each life-cycle stage in relation to the overall environmental and economic impact on residential building energy refurbishment projects. The results from the analysis of the refurbishment strategies at a case study in Spain show the relatively minor importance of the transport and end of life stages. The construction process stage is also of relatively minor importance regarding the environmental performance. The product, maintenance and replacement stages are generally of higher importance, particularly for economic evaluation. An extensive sensitivity analysis demonstrates the difficulties of simplifying the life-cycle boundaries, suggesting that potential simplifications should take into account various parameters, including the climate region, building typologies, and expected service life. As an example, the results have shown that for cold climate zones and buildings, where large energy savings from energy refurbishment strategies can be achieved, the other life-cycle phases are less important and, in most cases, represent less than 10% of life-cycle environmental impacts.Item An analysis of the potential of envelope-integrated solar heating and cooling technologies for reducing energy consumption in European climates(2018-06) Elguezabal, Peru; Arregi, Beñat; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓN; EDIFICACIÓN DE ENERGÍA POSITIVAThere is a clear trend towards the increased contribution of renewable energy at European level, and EU policies are oriented towards that direction. The building sector is no exception and presents an urgent necessity for increasing the share of renewable energy sources (RES) to reduce the impact on the environment. The aim of this paper is to examine the potential of solar heating and cooling technologies in reducing energy consumption by incorporating solar thermal and PV collectors within the building’s envelope. Although generally envisaged to be integrated in the roof, preferably oriented to the south, this study explores also their potential for integration into the façades. External climate influences both the demand for space heating and cooling (influenced by temperature) and the potential from solar renewable energy (incident global irradiation). However, a time lag exists since supply and demand peak at different times within the day as well as during the year. This study assesses the interplay of solar energy supply with heating and cooling energy demand. An analysis is performed over climate data files for five European locations, based on daily weather data. Besides the extent of incident solar irradiation, its seasonal usability is assessed with regard to the thermal demand. The impact of the inclination of solar collector devices is assessed by comparing their placement on a horizontal plane, on the inclination of maximum exposure for each climate, and on vertical planes for the four cardinal directions. As a conclusion, the utilization of solar energy for different scenarios is assessed and a discussion on the integration of solar thermal and PV collectors over façades is presented, building on the potential of these technologies for developing innovative solutions that could significantly upgrade the buildings’ energy performance in the near future.Item Automatised and georeferenced energy assessment of an Antwerp district based on cadastral data(2018-08-15) Oregi, Xabat; Hermoso, Nekane; Prieto, Iñaki; Izkara, Jose Luis; Mabe, Lara; Sismanidis, Panagiotis; Tecnalia Research & Innovation; PLANIFICACIÓN ENERGÉTICA; LABORATORIO DE TRANSFORMACIÓN URBANAMunicipalities play a key role in supporting Europe's energy transition towards a low-carbon economy. However, there is a lack of tools to allow municipalities to easily formulate a detailed energy vision for their city. Nevertheless, most municipalities have access to georeferenced cartographic and cadastre information, including that on basic building characteristics. This article describes an innovative method to calculate and display the current hourly thermal energy demand for each building in a district based on basic cartography, cadastre, and degree-day values. The method is divided into two main blocks: (1) input data processing to obtain geometric information (e.g. geolocation, building and facades’ dimensions) and semantic data (e.g. use, year of construction), and (2) district energy assessment to calculate the thermal energy demand using data obtained in block 1. The proposed method has been applied and tested in the historical district of Antwerp. The reliability and thoroughness of the results obtained using the method are demonstrated based on two different validations: (1) comparison of the results with those calculated using an existing dynamic energy simulation tool, and (2) comparison of the results with the real gas consumption of a partial sector of the selected district. The first validation shows that the average difference between the two methodologies is less than 11% for the heating demand, less than 11% for the cooling demand, and less than 15% for the domestic hot water demand. The second validation shows a 24% difference between the real natural gas consumption and that obtained by new methodology. Finally, the results have been presented to the municipality of Antwerp, which plans to use the method to design the district heating expansion within the city centre. Furthermore, sensitivity assessment was used to determine the relevance of the main input parameters considered in this method, such as the base temperature, energy system schedules, window-to-wall ratio, and solar gains.Item Bearing assessment tool for longitudinal bridge performance(2020-11-01) Garcia-Sanchez, David; Fernandez-Navamuel, Ana; Sánchez, Diego Zamora; Alvear, Daniel; Pardo, David; Tecnalia Research & Innovation; E&I SEGURAS Y RESILIENTESThis work provides an unsupervised learning approach based on a single-valued performance indicator to monitor the global behavior of critical components in a viaduct, such as bearings. We propose an outlier detection method for longitudinal displacements to assess the behavior of a singular asymmetric prestressed concrete structure with a 120 m high central pier acting as a fixed point. We first show that the available long-term horizontal displacement measurements recorded during the undamaged state exhibit strong correlations at the different locations of the bearings. Thus, we combine measurements from four sensors to design a robust performance indicator that is only weakly affected by temperature variations after the application of principal component analysis. We validate the method and show its efficiency against false positives and negatives using several metrics: accuracy, precision, recall, and F1 score. Due to its unsupervised learning scope, the proposed technique is intended to serve as a real-time supervision tool that complements maintenance inspections. It aims to provide support for the prioritization and postponement of maintenance actions in bridge management.Item BIM4Ren: Barriers to BIM Implementation in Renovation Processes in the Italian Market: Barriers to BIM implementation in renovation processes in the Italian market(2019-09-01) Elagiry, M.; Marino, V.; Lasarte, N.; Elguezabal, P.; Messervey, T.; E&I SEGURAS Y RESILIENTES; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓNAs a part of BIM4REN (Building Information Modelling based tools & technologies for fast and efficient RENovation of residential buildings) H2020 project, an analysis of the barriers of the renovation process, the potential of digitalization to overcome those barriers, and the requirements to ensure a successful digital workflow. This paper focuses on the Italian market where surveys, interviews, and a workshop were conducted, and then a diagnosis was made on the results obtained. Results show that technological innovation on BIM tools cannot be a stand-alone action to reach a full digitalization of the renovation sector, but it shall be supported by a major awareness of the actors involved, improved skills, and competences, as well as an important change of approach in the current construction practice.Item Bonding strength of stainless steel rebars in concretes exposed to marine environments(2018-05-30) Calderon-Uriszar-Aldaca, I.; Briz, E.; Larrinaga, P.; Garcia, H.; Tecnalia Research & InnovationMany studies have corroborated the use of Stainless Steel Reinforcements (SSR) for structures in corrosive environments. However, even though the conditions for their employment are specified in different standards, their use is always tied to the same requirements for standard carbon steel rebars (B500SD), among which an equivalent carbon content for weldability that is inappropriate for SSR. Further studies are therefore needed to develop suitable standards that will focus on addressing not only the content, but also the technical advantages of SSR for structural engineering under specific conditions. The results of this study show improvements in the maximum bond strength behaviour of different SSRs in simulated marine environments, in comparison with B500SD, in terms of several variables: Bond index, curing time, w/c ratio, and corrosion. Specifically, the test results showed that: (a) the Bond index was not a suitable parameter for the evaluation of the bonding strength of SSR; (b) the curing time increased the bonding strength of Lean Duplex Stainless Steel (LDSS); (c) a higher w/c ratio tended to decrease bond strength, although less so in LDSS; and, (d) corrosion reduced bond strength, especially in B500SD.Item Cable-driven parallel robot for curtain wall module installation(2022-06) Iturralde, K.; Feucht, M.; Illner, D.; Hu, R.; Pan, W.; Linner, T.; Bock, T.; Eskudero, I.; Rodriguez, M.; Gorrotxategi, J.; Izard, J.B.; Astudillo, J.; Cavalcanti Santos, J.; Gouttefarde, M.; Fabritius, M.; Martin, C.; Henninge, T.; Nornes, S.M.; Jacobsen, Y.; Pracucci, A.; Cañada, J.; Jimenez-Vicaria, J.D.; Alonso, R.; Elia, L.; Normes, S. M.; DIGITALIZACIÓN Y AUTOMATIZACIÓN DE LA CONSTRUCCIÓN; ROBOTICA_AUTOMA; Tecnalia Research & InnovationA cable-driven parallel robot (CDPR) was developed for the installation of curtain wall modules (CWM). The research addressed the question of whether the CDPR was capable installing CWMs with sufficient accuracy while being competitive compared to conventional manual methods. In order to develop and test such a system, a conceptual framework that consisted of three sub-systems was defined. The tests, carried out in two close-to-real demonstration buildings, revealed an absolute accuracy of the CWM installation of 4 to 23 mm. The working time for installing a CWM was reduced to 0.51 h. The results also show that the system is competitive for a workspace greater than 96 m2 compared to conventional manual methods. However, improvements such as reducing the hours for setting up the CDPR on the one hand and achieving a faster and more robust MEE on the other hand will be still necessary in the future.Item Characterization and thermal performance evaluation of infrared reflective coatings compatible with historic buildings(2018-04-15) Becherini, Francesca; Lucchi, Elena; Gandini, Alessandra; Casado Barrasa, Maria; Troi, Alexandra; Roberti, Francesca; Sachini, Maria; Di Tuccio, Maria Concetta; Garmendia Arrieta, Leire; Pockelé, Luc; Bernardi, Adriana; Tecnalia Research & Innovation; LABORATORIO DE TRANSFORMACIÓN URBANATwo infrared reflective coatings recently developed as part of the EFFESUS European research project are characterized and evaluated in this paper. Thermal performance, durability, compatibility with historic fabric, and reversibility are all analysed. The results of extensive research that include laboratory analysis of selected substrates, measurements on a large-scale traditional masonry mock-up, thermodynamic simulations, and finally application in to a real historic building in Istanbul, all support the potential of the new coatings to improve the thermal performance of historic buildings, in keeping with their visual integrity and cultural value. Besides their reflective properties, proven by the thermal stress reductions on the treated surfaces, the new coatings are characterized by low visual impact, easy application, material compatibility, and reversibility after application, as well as durability over time.Item Climate change risk assessment: A holistic multi-stakeholder methodology for the sustainable development of cities: A holistic multi-stakeholder methodology for the sustainable development of cities(2021-02) Gandini, Alessandra; Quesada, Laura; Prieto, Iñaki; Garmendia, Leire; Tecnalia Research & Innovation; LABORATORIO DE TRANSFORMACIÓN URBANACities are at risk due to global climate change, increasing both the frequency and the intensity of storms and extreme precipitation, sea-level rise, and other extreme weather events. Disaster risk reduction and adaptation to climate change should include a holistic and multi-scale perspective, to address the challenges of sustainable urban development and the conservation of the cultural value of our cities. In this research, an integral multi-stakeholder methodological approach is presented for risk assessment, supported by a data-collection and analysis strategy and a multi-scale urban model based on CityGML. A method of sampling buildings is presented together with the necessary data analysis, in order to perform the analysis at city scale. The methodology is implemented in Donostia- San Sebastián (northern Spain), a city located alongside a river estuary on the coastline. A sample of 2262 buildings are analyzed with varied characteristics at risk of extreme precipitation and/or storm surges and sea-level rise. The results demonstrated the effectiveness of the methodology at generating a unique risk index through a balance between the resources for data collection and the accuracy of the results, supported by a graphical 3D representation to facilitate results interpretation, and the subsequent evidence-based decision-making for prioritizing sustainable interventions.Item A comparison of thermal comfort conditions in four urban spaces by means of measurements and modelling techniques(2015-11-01) Acero, Juan A.; Herranz-Pascual, Karmele; Tecnalia Research & Innovation; CALIDAD Y CONFORT AMBIENTALMicroclimatic conditions inside urban areas depend on the result of the interaction of the regional climate with the whole urban area and on the local characteristics of the urban development. Inadequate human thermal comfort conditions can affect quality of life and the use of public open spaces. In this study, outdoor thermal conditions are examined through three field campaigns in Bilbao in the north of the Iberian Peninsula. Climate variables are measured in four different areas of the city in different regional climate conditions. Thermal comfort evaluation is undertaken by means of the thermal index PET (Physiological Equivalent Temperature). Measurements are compared with estimated values derived from ENVI-met model. Results show that the differences between modelled and measured climatic variables can imply a relevant deviation in PET (i.e. difference between modelled and measured values). Regression and correlation analyses account for the importance of the deviation of each climatic variable in the deviation of PET values. Deviation of PET appears to be highly conditioned by the deviation of mean radiant temperature values especially during clear sky days. Under overcast conditions deviation of wind speed also becomes a relevant aspect. Consequently, reliable estimation of these variables is required if modelling techniques are to be used in the assessment of thermal comfort in outdoor urban spaces.Item Comprehensive study on the most sustainable concrete design made of recycled concrete, glass and mineral wool from C&D wastes(2021-03-01) Gebremariam, Abraham T.; Vahidi, Ali; Di Maio, Francesco; Moreno-Juez, J.; Vegas-Ramiro, I.; Łagosz, Artur; Mróz, Radosław; Rem, Peter; TRAZABILIDAD CIRCULAR; GENERALThis study focuses on formulating the most sustainable concrete by incorporating recycled concrete aggregates and other products retrieved from construction and demolition (C&D) activities. Both recycled coarse aggregates (RCA) and recycled fine aggregates (RFA) are firstly used to fully replace the natural coarse and fine aggregates in the concrete mix design. Later, the cement rich ultrafine particles, recycled glass powder and mineral fibres recovered from construction and demolition wastes (CDW) are further incorporated at a smaller rate either as cement substituent or as supplementary additives. Remarkable properties are noticed when the RCA (4–12 mm) and RFA (0.25–4 mm) are fully used to replace the natural aggregates in a new concrete mix. The addition of recycled cement rich ultrafines (RCU), Recycled glass ultrafines (RGU) and recycled mineral fibres (RMF) into recycled concrete improves the modulus of elasticity. The final concrete, which comprises more than 75% (wt.) of recycled components/materials, is believed to be the most sustainable and green concrete mix. Mechanical properties and durability of this concrete have been studied and found to be within acceptable limits, indicating the potential of recycled aggregates and other CDW components in shaping sustainable and circular construction practices.Item Data driven model for heat load prediction in buildings connected to District Heating by using smart heat meters(2022-01-15) Lumbreras, Mikel; Garay-Martinez, Roberto; Arregi, Beñat; Martin-Escudero, Koldobika; Diarce, Gonzalo; Raud, Margus; Hagu, Indrek; Tecnalia Research & Innovation; EDIFICACIÓN DE ENERGÍA POSITIVAAn accurate characterization and prediction of heat loads in buildings connected to a District Heating (DH) network is crucial for the effective operation of these systems. The high variability of the heat production process of DH networks with low supply temperatures and derived from the incorporation of different heat sources increases the need for heat demand prediction models. This paper presents a novel data-driven model for the characterization and prediction of heating demand in buildings connected to a DH network. This model is built on the so-called Q-algorithm and fed with real data from 42 smart energy meters located in 42 buildings connected to the DH in Tartu (Estonia). These meters deliver heat consumption data with a 1-h frequency. Heat load profiles are analysed, and a model based on supervised clustering methods in combination with multiple variable regression is proposed. The model makes use of four climatic variables, including outdoor ambient temperature, global solar radiation and wind speed and direction, combined with time factors and data from smart meters. The model is designed for deployment over large sets of the building stock, and thus aims to forecast heat load regardless of the construction characteristics or final use of the building. The low computational cost required by this algorithm enables its integration into machines with no special requirements due to the equations governing the model. The data-driven model is evaluated both statistically and from an engineering or energetic point of view. R2 values from 0.70 to 0.99 are obtained for daily data resolution and R2 values up to 0.95 for hourly data resolution. Hourly results are very promising for more than 90% of the buildings under study.Item Design and testing of an adhesively bonded CFRP strengthening system for steel structures(2018-12-15) Chataigner, S.; Benzarti, K.; Foret, G.; Caron, J.F.; Gemignani, G.; Brugiolo, M.; Calderon, I.; Piñero, I.; Birtel, V.; Lehmann, F.; Tecnalia Research & Innovation; E&I SEGURAS Y RESILIENTESIn the framework of sustainable development policies, it is essential that infrastructure owners can rely on effective repair or strengthening solutions, designed and tested in relevance to actual service conditions. In the case of steel structures, fatigue damage is a major concern that can significantly affect the lifespan of the structure, and so far, there are very few operational methods capable of preventing fatigue cracks in the field. Adhesively bonded carbon fiber reinforced polymer (CFRP) composites are being successfully applied to the rehabilitation of concrete structures for more than two decades, and they are currently receiving much interest for the strengthening of steel elements, but mainly for curative purpose after severe damage has occurred. In the present study, which is part of a European project called FASSTbridge, a specific CFRP system has been developed as a preventive method against fatigue damage of steel structures. The proposed system consists of a commercially available ultra-high modulus (UHM) CFRP composite plate compatible with the stiffness of the host steel structures, which is bonded to the steel support using a novel hybrid epoxy/polyurethane adhesive. A first part of the paper presents the main specifications that should be adopted in the design of CFRP strengthening systems applied to steel structures, and that were identified from an extensive literature survey. These specifications have guided the development of the polymer adhesive and the choice of a peculiar commercial CFRP plate in the preliminary phase of the project. Experimental characterizations were then conducted (i) on the formulated hybrid polymer adhesive to optimize its curing schedule and check the previous specifications are fulfilled, and (ii) on CFRP reinforced steel specimens in order to verify the effectiveness of the proposed strengthening system. This experimental program involved both short term and durability tests that were performed by different laboratories. Such an inter-laboratory study made it possible to verify the performances of the developed strengthening system and to assess the influence of installation parameters and environmental conditions.Item Design of knowledge-based systems for automated deployment of building management services(2020-11) Schneider, Georg F.; Kontes, Georgios D.; Qiu, Haonan; Silva, Filipe J.; Bucur, Mircea; Malanik, Jakub; Schindler, Zdenek; Andriopolous, Panos; de Agustin-Camacho, Pablo; Romero-Amorrortu, Ander; Grün, Gunnar; Tecnalia Research & Innovation; LABORATORIO DE TRANSFORMACIÓN URBANA; EDIFICACIÓN DE ENERGÍA POSITIVADespite its high potential, the building's sector lags behind in reducing its energy demand. Tremendous savings can be achieved by deploying building management services during operation, however, the manual deployment of these services needs to be undertaken by experts and it is a tedious, time and cost consuming task. It requires detailed expert knowledge to match the diverse requirements of services with the present constellation of envelope, equipment and automation system in a target building. To enable the widespread deployment of these services, this knowledge-intensive task needs to be automated. Knowledge-based methods solve this task, however, their widespread adoption is hampered and solutions proposed in the past do not stick to basic principles of state of the art knowledge engineering methods. To fill this gap we present a novel methodological approach for the design of knowledge-based systems for the automated deployment of building management services. The approach covers the essential steps and best practices: (1) representation of terminological knowledge of a building and its systems based on well-established knowledge engineering methods; (2) representation and capturing of assertional knowledge on a real building portfolio based on open standards; and (3) use of the acquired knowledge for the automated deployment of building management services to increase the energy efficiency of buildings during operation. We validate the methodological approach by deploying it in a real-world large-scale European pilot on a diverse portfolio of buildings and a novel set of building management services. In addition, a novel ontology, which reuses and extends existing ontologies is presented.Item Development of ultra-high performance concretes with self-healing micro/nano-additions(2017-05-01) García Calvo, J. L.; Pérez, G.; Carballosa, P.; Erkizia, E.; Gaitero, J. J.; Guerrero, A.; Gerrero, A.; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓN; Tecnalia Research & InnovationUHPC are developed in present paper incorporating an innovative self-healing system based on two micro/nano-additions: silica microcapsules containing epoxy sealing compound (CAP) and amine functionalised silica nanoparticles. Although CAP are well integrated within the cementitious matrix, their inclusion promotes a reduction in the mechanical performance so CAP could act as weak points. However, the inclusion of these additions refines pore distribution thus increasing the expected durability in aggressive media. An effective autonomous self-healing capacity is assessed/confirmed which is unexpectedly higher in the concretes with the lower healing additions content studied. This capacity depends on the crack width and the healing period considered.Item Direct route from ethanol to pure hydrogen through autothermal reforming in a membrane reactor: Experimental demonstration, reactor modelling and design: Experimental demonstration, reactor modelling and design(2018-01-15) Spallina, V.; Matturro, G.; Ruocco, C.; Meloni, E.; Palma, V.; Fernández-Gesalaga, E.; Melendez, J.; Pacheco Tanaka, David A.; Viviente Sole, J.L.; van Sint Annaland, M.; Gallucci, F.; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThis work reports the integration of thin (∼3–4 μm thick) Pd-based membranes for H2 separation in a fluidized bed catalytic reactor for ethanol auto-thermal reforming. The performance of a fluidized bed membrane reactor has been investigated from an experimental and numerical point of view. The demonstration of the technology has been carried out over 50 h under reactive conditions using 5 thin Pd-based alumina-supported membranes and a 3 wt%Pt-10 wt%Ni catalyst deposited on a mixed CeO2/SiO2 support. The results have confirmed the feasibility of the concept, in particular the capacity to reach a hydrogen recovery factor up to 70%, while the operation at different fluidization regimes, oxygen-to-ethanol and steam-to-ethanol ratios, feed pressures and reactor temperatures have been studied. The most critical part of the system is the sealing of the membranes, where most of the gas leakage was detected. A fluidized bed membrane reactor model for ethanol reforming has been developed and validated with the obtained experimental results. The model has been subsequently used to design a small reactor unit for domestic use, showing that 0.45 m2 membrane area is needed to produce the amount of H2 required for a 5 kWe PEM fuel-cell based micro-CHP system.Item Disaggregation process for dynamic multidimensional heat flux in building simulation(2017-08-01) Garay, Roberto; Riverola, Alberto; Chemisana, Daniel; Martinez, Roberto Garay; Tecnalia Research & InnovationHeat transfer across envelopes (façade, roof, glazed areas) represents a big share of the energy flow within the heat balance of buildings. This paper focuses on areas of the envelope where multi-dimensional heat transfer occurs. These areas are commonly defined as thermal bridges, due to a localized reduction of thermal resistance of constructions in these places. This paper reviews common standardized methods to assess heat transfer in buildings, under various modelling assumptions: one-dimensional, multi-dimensional, steady state and dynamic. Within presently developed modelling and assessment methods, a need for improvement has been identified over existing methods for the thermal assessment of multi-dimensional heat transfer under dynamic conditions. A phasorial approach to differential heat transfer in thermal bridges has been developed, which serves as the dynamic extension of steady-state thermal bridge coefficients. This formulation is applied to the junction of a masonry wall with a concrete slab.Item ELECTRIC ARC FURNACE SLAG AND ITS USE IN HYDRAULIC CONCRETE(2015-08-15) Arribas, Idoia; Santamaria, Amaia; Ruiz, Estela; Ortega-Lopez, Vanesa; Manso, Juan M.; TRAZABILIDAD CIRCULARElectric arc furnace oxidizing slag (EAFS) is a by-product of the steelmaking industry, generated after the melting and the preliminary acid refining of liquid steel. It is a stony material that is easy to crush for use as aggregate in concrete mixes. This study examines the long-term aging reactions of EAFS and its volumetric stability, to gain further knowledge of this by-product, its behaviour as a construction material, and its inherent risk of swelling. Additionally, the good compressive strength of hydraulic mixes that incorporate this slag can be analyzed and explained on the basis of its steady and expansive compounds and its chemical evolution over time in the interfacial transition zone (ITZ); the appearance of calcium carbonate enhances the cohesiveness, stiffness and strength of this zone and, as a consequence, of the hydraulic concreteItem Experimental and numerical thermal performance assessment of a multi-layer building envelope component made of biocomposite materials(2020-05-01) Arregi, Beñat; Garay-Martinez, Roberto; Astudillo, Julen; García, Miriam; Ramos, Juan Carlos; Tecnalia Research & Innovation; EDIFICACIÓN DE ENERGÍA POSITIVA; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓNBuilding envelope systems are rapidly evolving, driven by increasingly stringent requirements for limiting energy consumption. Current trends favour lightweight, prefabricated wall assemblies with high levels of insulation, which have been shown to be particularly sensitive to thermal bridging through anchoring and framing elements. This paper presents a self-supporting multi-layer wall component made from bio-based materials, where novel biocomposite profiles are used instead of conventional metallic frames. The thermal performance of the proposed solution is calculated from numerical modelling and characterised through in-situ measurement of a full-scale prototype. For the plane areas of the wall with continuous insulation, theoretical calculations are broadly in line with results from experimental monitoring (7–15% deviation). Additionally, an area along a framing profile was specifically monitored, and it was found that the numerical model overestimated thermal resistance with a deviation of 121%. The presence of air gaps between the rigid insulation and framing elements, linked to the fabrication process of the prototype, was identified as a plausible cause. A subsequent explanatory numerical assessment, considering the effect of such cavities in the numerical model, provided results that are consistent with measurements from the experiment and previous literature. The study aims at demonstrating the insulation levels achievable with the use of novel bio-based materials of low thermal conductivity, and more generally, contributing to a better understanding of the thermal performance of framed lightweight insulated assemblies in service conditions, by monitoring and modelling the impact of thermal bridges and workmanship at framing elements.
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