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Study of the Deformation Capacity of Corroded Passive Rebars
No full textThe steel used as passive reinforcements in reinforced concrete structures must have certain resistance requirements and also meet minimum ductility condi-tions. The ductility requirements have increased significantly since the 1980s as a result of the increasing use of analysis procedures for reinforced concrete structures based on the limited redistribution of moments and the greater concern in the calcu-lations of structures located in seismic zones where a greater capacity of deformation energy consumption of the structures is needed, an aspect closely linked to ductility, or in structures where stresses cannot be quantified with sufficient precision. There are different ways of assessing the ductility of a reinforcement that have changed over time. In Spain, three criteria have been used for decades to define the ductility of a reinforcement: (i) quotient between the breaking stress and the elastic limit; (ii) deformation measured at the point of maximum stress and (iii) breaking strain measured in 5 diameters. In many internationally used regulations of the above three parameters the first two are used, but the third is not considered. In the present study, 68 B 500 SD steel trusses have been subjected to a corrosion procedure, measuring the loss of midsection, testing for traction and obtaining the two deformation param-eters that take into account the Spanish regulations. The results indicate that, for corroded armor, there is no relationship between them
Development of a bim add-in for the quantification and reduction of construction waste in residential buildings in Andalusia
No full textLa industria de la construcción es un sector económico clave en el desarrollo sostenible del modelo productivo mundial, cuya actividad representa, al mismo tiempo, una de las mayores amenazas para el medioambiente. En Europa, por ejemplo, es la principal fuente de residuos y la mayor consumidora de recursos. Por esta razón la Unión Europea (UE) ha establecido un nuevo Plan de Acción para mejorar el uso eficiente de recursos y convertirse en una Economía Circular en la que se reduzca, entre otros, la generación de Residuos de Construcción y Demolición (RCD). Existe consenso en la literatura en que la fase de diseño del proyecto de un edificio o una infraestructura es crucial para reducir los Residuos de Construcción (RC), para eliminar las causas fundamentales de su generación. Modelos de producción como los del “lean construction”, “zero waste”, o “economía circular”, destacan la importancia de reducir los RC en su origen, en lugar de reciclarlos y recuperarlos. Sin embargo, uno de los principales problemas para lograr modelos de construcción de baja generación de residuos es la falta de instrumentos eficaces integrados en las propias herramientas de diseño, que permitan la estimación precisa de los RC durante las fases iniciales del proyecto. En este sentido, en los últimos años, la metodología BIM (Building Information Modelling) ha ganado relevancia en los procesos de digitalización del ciclo de vida de un edificio. Con gran capacidad para manejar y compartir datos, BIM se ha convertido en una herramienta eficaz para la simulación del comportamiento ambiental del edificio durante la fase de diseño, brindando así una oportunidad para evaluar los RC a nivel de proyecto. La principal hipótesis de esta Tesis doctoral se fundamenta en que la arquitectura debe constituir un activo ambiental ante el cambio climático. Por tanto, el objetivo principal de esta investigación es dotar a los diseñadores de una herramienta tecnológica digital implementada en la metodología BIM, que les permita tomar decisiones basadas en el conocimiento detallado de la cantidad de RC que produce el diseño ideado en una fase temprana del desarrollo de un proyecto. Para ello, se propone integrar un modelo matemático de cuantificación de RCD, validado, en el entorno de la metodología BIM. En ese sentido, la Tesis realiza un recorrido metodológico de complejidad creciente en relación con: el nivel de automatismo de los procesos de cálculo, las opciones de análisis de resultados, el empleo de entornos de trabajo BIM y el desarrollo de la arquitectura informática; a medida que la intervención del usuario-diseñador se va reduciendo en cuanto a la introducción de datos y el conocimiento específico en la gestión de los RC y su impacto ambiental obtenido a partir del Análisis del Ciclo de Vida (ACV) de un edificio. Mediante este recorrido metodológico se constata la capacidad de implementación que tiene el modelo de cuantificación de RCD seleccionado en la metodología BIM. Los resultados proporcionan evidencia de que los métodos propuestos permiten la identificación y cuantificación automática de los RC generados por cada elemento del edificio durante la etapa de diseño, así como el conocimiento del impacto ambiental causado por su gestión. Disponer de información fiable, comparable y verificable resulta fundamental para que el diseñador pueda tomar decisiones más sostenibles acordes con las directrices de la economía circular.Construction is an important economic sector for the sustainable development of the global production model, and its activities are also one of the most serious environmental threats. For example, in Europe, it is the main source of waste and the main consumer of resources. Therefore, the European Union (EU) has developed a new Action Plan to improve resource efficiency and to become a circular economy, including reducing the production of Construction and Demolition Waste (CDW). The literature consensus has been that the design stage of building or infrastructure projects is crucial to reducing Construction Waste (CW) by eliminating the basic causes of its production. Production models such as “lean construction”, “zero waste”, or “circular economy”, highlight the importance of reducing CW at its source, instead of recycling and recovering it. However, one of the main problems in achieving low waste construction models is the lack of effective instruments integrated into the design tools, which allow accurate estimation of the CW during the initial phases of the project. In this respect, in recent years, the BIM methodology (Building Information Modelling) methodology has gained relevance in the digitisation processes of the life cycle of a building. Given its ability to handle data, BIM has become an effective tool for simulating the environmental behaviour of the building during the design phase, thus providing an opportunity to assess CW at the project level. The main hypothesis of this Thesis is that architecture should be an environmental asset facing climate change. Therefore, the main objective of this research is to provide designers with a digital technological tool implemented in the BIM methodology, which allows them to make decisions based on detailed knowledge of the amount of CW produced by the design developed in an early stage of the project. For this, a validated CDW quantification mathematical model is proposed in the context of the BIM methodology. In this regard, the Thesis carries out a methodological journey of increasing complexity in relation to the level of automation of the calculation processes, the options for analysis of results, the use of BIM work environments, and the development of computer architecture; as the intervention of the user-designer is reduced in terms of data entry and specific knowledge in the management of CW and its environmental impact obtained from the Life Cycle Analysis (LCA) of a building. Through this methodological journey, the implementation capacity of the CDW quantification model selected in the BIM methodology is verified. The results provide evidence that the proposed methods allow the identification and automatic quantification of the RC generated by each element of the building during the design stage, as well as the knowledge of the environmental impact caused by its management. Having reliable, comparable, and verifiable information is essential for the designer to make more sustainable decisions according to the guidelines of the circular economy
Impact of Environmental Conditions on Construction Materials Throughout Long-Term Surveys to Promote Preventive Conservation. Case Study of Courtyards Located in Mediterranean Climate
No full textThis chapter presents the environmental conditions linked to the micro-climate developed in the Mediterranean courtyards, in order to know the impact on the conservation of traditional building materials. Thus, this work aims to estab-lish a relationship between environmental parameters (Temperature and Relative Humidity) and the preservation of plasterworks, wooden carpentries and ceilings, and tilings. Results will easily reveal which are the most adequate conditions of conservation of these materials and the influence of ambient conditions in the degra-dation process of materials present in the Courtyard of the Maidens (Royal Alcazar of Seville). To this end, a long-term monitoring of the environmental conditions of the Courtyard of the Maidens was carried out during 2021 and 2022 and the subsequent statistical analysis of the parameters
Effects of High Temperatures on Concrete with Recycled Aggregates from Ceramic Stoneware Waste
No full textThe Spanish ceramic tiles industry is a major player on the market, with an annual production of 587 million m2, that generates around 4,855 million euro. Most of this production (94%) is concentrated geographically in a cluster in the province of Castellón (Spain). However, it is estimated that around 1.5–2% of the ceramic products contain defects or cracks, most of which ends up in landfills. Ceramic stoneware is a type of ceramic known for its strength and durability that is created at very high temperatures (1,200ºC). This study examines using waste ceramic stoneware as a recycled aggregate to create structural concrete and its properties at high temperatures. Five concrete mixes are studied: the reference, and different replacements of natural calcareous sand and gravel with fine and coarse ceramic stoneware waste. The study evaluates the properties of aggregates, such as size distribution, density, absorption, and hardness, and looks at the properties of the resulting concrete mixes. Concrete is tested for compression, and also for thermal conductivity at room temperature. Concretes compressive strength is also evaluated after being exposed to high temperatures (200ºC, 400ºC, 600ºC, 800ºC), with air cooling. The results show that the strength values obtained at room temperature are similar in all the mixes. Thermal conductivity decreases as the percentage of ceramic waste rises. Finally, replacing natural aggregates with ceramic stoneware offers significant improvements to concrete’s residual compressive strength after being exposed to 400ºC and 600ºC. This was observed mainly with a high replacement percentage. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG
The Thermal Potential of Wastewater for Heating and Cooling Buildings: A Case Study of a Low Exergy Building in Madrid
No full textThe use of technologies that allow for the utilization of renewable energies wasted around buildings is one of the ways to ensure the decarbonization of the sector. Wastewater from buildings is a renewable source of thermal energy. Groundwater and rainwater are important components of wastewater that flow into sewerage systems. The main objective of this research is to estimate the thermal potential of wastewater for the heating and cooling of buildings. In this paper, an office building with a low-energy system (TABS) was studied for one year to assess the energy contribution of wastewater in a hybrid system that includes geothermal exchangers and a wastewater exchanger. This study shows that wastewater from sewerage systems that flows faster than 5 L/s can make enough heat to power an office building with a power demand of 45 kW (60 W/m2). The energy contribution of wastewater from the sewerage system is more favorable in heating scenarios than in cooling ones, improving the system efficiency by over 22% compared to geothermal systems. Rainwater enhances cooling efficiency by over 14% compared to geothermal systems. This finding could help to establish a predictive method or guidelines for the design and sizing of heat exchangers in sewerage systems. © 2023 by the authors
¿Cómo afectan la forma urbana y las diferencias socioeconómicas a la temperatura de un distrito residencial?
No full textUrban temperature is crucial to reach world sustainable development goals. This could affect building energy consumption and human thermal comfort, among other social, economic, and environmental issues. Meanwhile, cities can aggravate such problems by generating the phenomenon of urban heat islands (UHI). The main purpose of this research is to classify the urban form of Temuco city, Chile, and simulate the urban temperatures in several socioeconomic districts to understand how these differences could affect the neighborhoods in terms of house-building energy and thermal performance. For this, the local climate zone classification methodology was applied, then the urban weather generator (UWG) software was used to perform the different climate files. Also, data loggers were installed in the studied districts to validate the simulations in UWG. The results showed that low-income neighborhoods have higher UHI intensity reaching 9.5°C, while high-income neighbourhoods have UHI intensity as high as 5°C. These results can strongly affect the building energy performance in energy-vulnerable districts once all cities have the same energy and thermal official standards. Future investigations will be carried out to better understand how housing stock is affected. © 2023 by The authors
Analysing energy poverty in warm climate zones in Spain through artificial intelligence
No full textUsing automated tools to detect energy poverty (EP) is a developing field. Artificial intelligence and data mining could be used to provide solutions to reduce EP cases. As for Spain, there is no study addressing this characterization that could be significant in warmer zones of the country (i.e., the most exposed zones to climate change). Simulated energy consumption data were used with data of energy prices and family units incomes based on the public income indicator of multiple effects (IPREM in Spanish). In addition, the high share of energy expenditure in income (2 M) was used to assess EP. A total of 36,230,400 cases were simulated to train and test 312 prediction models, 104 by each algorithm. The algorithms were multilayer perceptron (MLP), random forest (RF), and M5P. The results showed that these three algorithms were appropriate, with tree-type models obtaining better estimates. For greater effectiveness, prediction models should also be used for the income threshold considered in their development. The results also showed the utility of artificial intelligence in the prediction of EP without performing an energy analysis in detail, thus optimizing energy managers and social workers work. In addition, prediction tools could be used to estimate monthly family units’ EP situation. © 2023 Elsevier Lt
Utilisation of Ceramic Stoneware Tile Waste as Recycled Aggregate in Concrete
No full textThe construction industry has a significant environmental impact and concrete production is responsible for a large part of CO2 emissions and energy consumption. This study focused on the reutilisation of a specific type of tiles ceramic waste (TCW), composed only of stoneware and porcelain stoneware tiles, hereafter referred to as ceramic stoneware (CS), as recycled aggregate in concrete. Natural limestone and CS aggregates (sand and gravel) were characterised (particle size distribution, water absorption, resistance to wear, density and X-ray diffraction analyses) and recycled aggregate concrete (RAC) was prepared by replacing 20, 50 and 100 vol.% of sand and gravel, separately. Concrete workability generally improved with CW addition, especially when replacing natural gravel. Although the compressive strengths of the concrete specimens prepared with recycled sand were slightly lower than those of the reference specimens, similar or better results were recorded with the recycled CS gravel. In consonance, the RAC developed with recycled gravel obtained lower water penetration depths than the reference concrete. No significant variation in tensile strength was observed when varying CS content (values within the 2.33–2.65 MPa range). The study contributes to sustainable construction practices and circular economy by promoting the valorisation and reutilisation of industrial waste and reducing the consumption of natural resources. © 2023 by the authors
Risk Factors for Working Pregnant Women and Potential Adverse Consequences of Exposure: A Systematic Review
No full textObjective: To assess the risk factors perceived as stressors by pregnant women in the work environment and the possible adverse consequences of such exposure for the normal development of pregnancy. Methods: Systematic review, guided by the PRISMA guidelines, and using Pubmed, Web of Science, Dialnet, SciELO, and REDIB databases. Methodological quality was assessed using the critical appraisal tools for non-randomised studies of the Joanna Briggs Institute. Results: A total of 38 studies were included. The main risk factors found in the work environment of pregnant women were chemical, psychosocial, physical-ergonomic-mechanical factors, and other work-related factors. The main adverse consequences of exposure to these factors include low birth weight, preterm birth, miscarriage, hypertension and pre-eclampsia, as well as various obstetric complications. Conclusion: During pregnancy, working conditions that are considered acceptable in normal situations may not be so during this stage due to the major changes that occur during pregnancy. Many obstetric effects may have an important impact in the mother’s psychological status; therefore, it is important to optimise working conditions during this stage and to reduce or eliminate possible risks. Copyright © 2023 Corchero-Falcón, Gómez-Salgado, García-Iglesias, Camacho-Vega, Fagundo-Rivera and Carrasco-González
Feasibility of Ecofriendly Mortars with Different Hemp Additions for Use in Building Sector
No full textCement mortars are commonly used in building works for the execution of enclosures and exterior rehabilitation of facades. The incorporation of plant-based additives enables the development of ecofriendly construction materials. In this work, a physical and mechanical characterisation of cement mortars with the incorporation of hemp in three morphologies (fibre, powder and pellet) was conducted. The results show how the additions of hemp powder and pellets with a partial replacement of natural aggregate reduce the final density of cement mortars and their thermal conductivity by more than 16% and 19%, respectively. On the other hand, the addition of hemp fibres reduces shrinkage during the setting of cement mortars, improving their flexural strength and increasing their durability. For this reason, it is possible to recommend the use of these mortars with the addition of natural hemp fibres without prior surface treatment to improve the physical-mechanical properties of these construction materials and extend their application field as ecofriendly materials for masonry work. © 2023 by the authors