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Investigation of gypsum composites with different lightweight fillers: A physico-mechanical characterisation regarding possibilities for building applications
No full textThis paper shows the characterization of a new lightened gypsum-based material for use in buildings. Super absorbent polymer (SAP) Potassium Polyacrylate has been used as main lightener leading to a 20% density reduction. In addition, tests have been carried out with the lightened plaster material reinforced with vermiculite (VER), recycled glass wool (RGW), expanded clay (EC). A significant improvement in physical properties was achieved. After material evaluation, a new precast design was elaborated and tested for its use in building. Physical-mechanical properties of these new material have been studied. A complementary ignitability test was also conducted to set this materials suitability for its use in building. All samples performed over standard minimum requirements. Samples containing RGW obtained best results in both, thermal conductivity, and acoustic absorption. © 2023 Elsevier Lt
Development and Intervention Proposal with Earthen Refurbishments with Vegetal Origin Gel (VOG) for the Preservation of Traditional Adobe Buildings
No full textThis research focuses on the addition of an ecological, sustainable material to improve the durability of earthen constructions and for use in rehabilitation and restoration processes. Specifically, it studies the mechanical and waterproof performance of an earthen mixture with the addition of a vegetal origin gel (VOG) obtained by extracting the starch contained in rice. This solution increases the durability of the mixture and the behavior against water and improves the mechanical resistance of the system. This study is divided into two parts. First, an experimental phase was carried out in the Universitat Politècnica de Catalunya laboratory to design and develop the earthen mixtures stabilized with VOG to obtain an ecological, economical and easily replicable technology that can be transferred to any population group. The second stage consisted of the application of these mixtures and a real intervention in adobe dwellings in the community of Santa Ana Chapitiro, in the State of Michoacan, Mexico. The rehabilitation solutions and dosages were transferred to the residents of the community and applied to local adobe constructions by means of participatory design through an international development cooperation project. Good behavior of the material was found in the early stage. © 2023 by the authors
Is the analysis scale crucial to assess energy poverty? analysis of yearly and monthly assessments using the 2 M indicator in the south of Spain
No full textEnergy poverty has been addressed as a global problem. Many studies have been conducted, and several indicators have been established to detect energy poverty. However, most analyses have been performed at a yearly level without considering the differences throughout the year. This study performed a sensitivity analysis to determine these differences using the 2 M indicator in 36,230,400 case studies in the south of Spain, which is a warm zone with great energy poverty, as well as vulnerable to climate change effects. The results showed that monthly assessment could increase energy poverty situations in the months with greater climate severity, compared to yearly assessment. That increase in winter and summer months raised energy poverty cases over 20 %, with these months being those with greater vulnerability due to cold and heat waves, respectively. The results also showed that variations were independent of both the technical characteristics of the dwelling and the use of HVAC systems. Energy poverty cases were reduced only in the summer months with the adaptive approach, which considers thermal adaptation. The use of the 2 M indicator in monthly scales can detect vulnerable family units that cannot be detected by yearly studies, so monthly scales are crucial for governments to adopt energy poverty policies and strategies. © 2023 Elsevier B.V
A quarry for the construction of a Roman camp next to the Celtiberian city of Deza during the Sertorian Wars (Soria, Spain)
No full textThrough an interdisciplinary investigation, a hastily exploited individual quarry of limestone is studied. The quarry was made all at once for the construction of a nearby military camp to improve the defence of a remarkable Celtiberian city during the Sertorian Wars. This is a perfect Roman military engineering project: on the one hand, the geological deposit was exploited selectively, differentiating the areas of extraction of large and small blocks of stone, according to the needs of the work. On the other hand, the material was transported by means of small roads along a carefully studied and laid out road of about 600 m in length and of clear Roman origin. The archaeological evidence shows the existence of a large camp that, according to previous surveys, adopts the known classical models of rectangular plans and the typology of Roman construction. In the camp environment, there are enough scattered remains that seem to point to a battlefield. All this indicates the importance of the primitive Celtiberian settlement, which is justified by an analysis of the territory by the existence of springs of high guarantee for human water supply, livestock and irrigation. The existence of silver mines is another added economic value. Due to the predominance in the monetary findings of the mint of Titiakos, the possibility is raised that the Celtiberian city was linked to the ethnic group of the Titos indicating their active participation during the Sertorian Wars. © 2023, The Author(s)
Linking occupational accidents and construction firm survival
No full textIntroduction: This paper examines the relationships between the reported accidents of workers in construction firms and the probability of those firms’ survival. Method: Between 2004 and 2010, a sample of 344 Spanish construction firms from Majorca were selected. The study built panel data with the reported official accidents from the Labor Authority records and the firm survival or mortality from the Bureau van Dijḱs Iberian Balance Sheet Analysis System database. The hypothesis is that a higher number of accidents directly affects the probability of the company surviving in the sector. By using a probit regression model with panel data, the relationship between these two variables were explored to test the hypothesis. Results: The study found evidence that an increment in accidents decreases the probability of the company continuing to operate, or worse, going bankrupt. The results can be useful to highlight the importance of defining policies to control those accidents effectively, since this may be a key factor in the sustainability, competitiveness, and growth of the construction sector for the economy of a region. © 2023 The Author(s
Mechanical behaviour of poplar laminated veneer lumber with fiber reinforced polymer under shear and compression stresses
No full textThis paper presents experimental results of the mechanical behaviour of LVL (Laminated Veneer Lumber) made of poplar reinforced with fiber reinforced polymer (FRP) subjected to shear and compressive stresses. Through mechanical properties such as strength, stiffness, maximum displacement and non-destructive measurements of elastic moduli in compression and shear, the influence of different variables was analysed: 1) Type of FRP (carbon or basalt); 2) Fiber direction; 3) Quality of veneer. The influence of veneer quality under compressive stresses and the difference between carbon and basalt under shear stresses have been verified. In addition, for the unidirectional carbon reinforcement, improvements up to 21% in compressive and shear stiffness and elastic modulus was achieved, respectively. © 2022 Informa UK Limited, trading as Taylor & Francis Group
Examining urban polarization in five Spanish historic cities through online datasets and onsite perceptions
No full textAt present, the planning and management of historic districts are faced with the challenge of striking a balance between the needs of residents and seasonal pressures from visitors. These socially bustling sites could also benefit from the data cross-referencing of cultural and social patterns in order to identify areas for improvement. This research analyses geo-referenced online datasets and data from social media applications, subsequently contrasting these with onsite data from in-person interviews. These specific variables highlight parallels and conflicts between districts designated World Heritage areas in five Spanish cities. The study provides a quantitative analysis of hotspots and coldspots within the built environment. This is followed by an examination of these two types of areas using qualitative data linked to the three most challenging issues: housing and the built environment; basic services; and cultural services. When analysing the future of historic districts three major challenges to management highlighted in the results should be considered. Firstly, even in socially active districts, imbalances and dysfunctional areas are highlighted by both online data and onsite perceptions. Secondly, the study of the dynamics of districts for observing how stakeholders adapt to this social, economic, and mobility-related polarization. Thirdly, while the study acknowledges the changes to the consumption of culture, there is still potential for improvement in hosting alternative or countercultural movements. © 2023 The Author
Non-audible acoustic emission characterization of Reticulitermes termites in pine wood
No full textThis research evaluates and characterizes the acoustic emission activity generated by Reticulitermes termites as recorded by piezoelectric sensors with sensitivity in the ultrasound range (greater than 20 kHz). To this end, the acoustic emission activity was recorded under controlled conditions of temperature and moisture content in three pine wood samples in which termites were artificially inoculated: only soldiers, only workers, or a colony of workers and soldiers. Different traditional parameters of the acoustic emission signals were analyzed, in both the time and frequency domains. This study proved feasible to use acoustic emission to detect the activity of this kind of termites, although it was not possible to distinguish between workers and soldiers. It is also demonstrated that, by using several sensors, one can locate the activity of the insects, a finding of great practical interest for the accurate detection of colonies in real buildings. © 2023, The Author(s)
Consideration of natural ventilation through transient simulation models using TRNFlow
No full textSon muchas las variables a considerar al diseñar un edificio sostenible o pasivo en el que se debe reducir el consumo energético. Tenemos claro que la ventilación natural produce un efecto positivo en climas cálidos al considerar el confort en el interior o reducir al máximo la demanda energética. Cómo considerar el efecto que tiene la ventilación natural dependiendo de las condiciones climáticas del momento es lo que se debemos considerar en programas de cálculo con modelos BEM (Building Energy Model) que trabajan en régimen transitorio. Es habitual considerar un valor constante de ventilación ya que simplifica mucho el cálculo, pero no siempre nos dará un resultado real. En este trabajo se pretende analizar cómo considerar la ventilación natural dependiendo del diseño arquitectónico de los espacios habitables y de las condiciones climáticas exteriores, y cómo afecta sobre los resultados finales obtenidos. Para este trabajo se utiliza un modelo BEM considerando las variables de ventilación constantes o transitorias (variables en función de la velocidad del viento y la dirección en función del diseño del edificio). El programa utilizado es TRNSYS con la herramienta de TRNFlow
Use of eggshell waste: A green and effective method for the synthesis of pure calcium hydroxide suspensions
No full textThis paper presents a rapid method to obtain pure suspensions of Ca(OH)2 dispersed in 2-propanol. To this aim eggshell wastes (CaCO3) were decarbonated to calcium oxide (CaO) followed by sonication-assisted hydrolysis in water/2-propanol to form calcium hydroxide (Ca(OH)2). An important advantage of the method is that it does not require chemical reagents due to the high purity of eggshell in CaCO3. Moreover, CaO is fully converted into Ca(OH)2 which means that purification steps are not needed, as occurs in conventional routes of synthesis. To assess the reliability of the synthetic procedure, the purity and amount of Ca(OH)2 were studied by X-ray diffraction (XRD), infrared spectroscopy (FTIR) and thermal analysis (TG). In addition, the morphology and crystallite size were examined by transmission electron microscopy (TEM) and X-ray diffraction (XRD) using Rietveld refinement method. It was found that sonicated Ca(OH)2 suspensions (5 g/L) were composed of particles that ranged in size from several nanometers to few micrometers. Finally, the suitability of Ca(OH)2 from eggshell to reinforce architectural stone was also studied by microscopy examination, colour change tests, surface hardness and surface erosion measurements. All tests confirmed the consolidation effectiveness was comparable to conventional nanolime treatments and surface erosion was visibly reduced. © 2023 The Author