Committee:
     PRESIDENT: GAUSA NAVARRO, MANUEL
     SECRETARI: LÓPEZ LÓPEZ, DAVID
     VOCAL: NEILA GONZÁLEZ, FRANCISCO JAVIER
Thesis abstract: This doctoral thesis aims to develop an Additive Manufacturing technique for the production of Ceramic Building Elements with controlled variable density. The research seeks to provide an alternative to the currently available building elements in the construction industry, focusing on the design of construction elements with specific characteristics through the manipulation of porosity.The hypothesis suggests that Additive Manufacturing technologies can be used to produce ceramic materials with controlled variable density, which could replace conventional systems composed of ceramics and complementary layers of different materials. Unlike other works, this proposal allows for the establishment of pore size and connectivity.The work methodology is divided into two complementary parts. On one hand, it focuses on developing the manufacturing means, including hardware and software, while on the other hand, it studies the resulting product, namely, the printed ceramics with variable density. A research, design, and construction process are carried out, which includes different steps such as studying the state of the art in additive manufacturing and materials with gradient function, selecting and constructing a 3D printer, developing a clay extrusion system adapted to the machine, calibrating the manufacturing process, defining porosity limits, creating design strategies, and manufacturing demonstration pieces.The results of this research will have broader implications in the field of architecture and construction. The additive manufacturing technique with controlled variable density will enable the creation of mono-material systems with improved properties, opening new possibilities in the design and construction of building elements. Furthermore, the use of a single constituent material with density variations can contribute to optimizing the management of construction waste and reducing the environmental impact of the industry. This research can also drive the advancement of additive manufacturing in producing materials with gradient function in various sectors, including aerospace and materials engineering.In summary, this doctoral thesis aims to develop an Additive Manufacturing technique for producing Ceramic Building Elements with controlled variable density. The methodology is based on research, design, and construction of manufacturing means, as well as the study of the resulting product. The results of this research will have implications in the design and construction of building elements, as well as in the advancement of additive manufacturing in other industrial sectors.

Committee:
     PRESIDENT: ARMENGOU ORÚS, JAUME
     SECRETARI: CASANOVAS RUBIO, MARIA DEL MAR
     VOCAL: COMA ARPON, JULIÀ
Thesis abstract: Environmental protection is a principle of both Millennium Development Goals and sustainable development, underscoring critical issues like greenhouse gases, global warming, and air pollution. Air pollution is a global challenge with severe consequences for the environment. Hence, city managers encounter an urgent need to explore the proper solutions to mitigate air pollution.This doctoral dissertation addresses air pollution reduction by harnessing the untapped potential of rooftops while focusing on pollutant reducers and taking into account specific characteristics of urban buildings. The study follows a five-phase framework, including initial investigation, feasibility study, solution exploration, sustainability evaluation, and city-scale optimization.The research method proposed in this thesis is validated for the first time in the context of Tehran, a densely populated and highly air-polluted megacity. The key achievements of this leading application encompass: feasible alternatives, sustainability assessment, optimal solutions, target building groups, and city-scale impact. Firstly, considering sustainability, effectiveness, and viability, the study identifies green roofs (GR) and photovoltaic (PV) systems as feasible rooftop-based alternatives. Second, novel sustainability assessment models are developed, combining methods like the Integrated Value Model for Sustainability Assessment (MIVES), Strengths-Weaknesses-Opportunities-Threats (SWOT), Analytic Hierarchy Process (AHP), simplified Life Cycle Assessment (LCA), and sensitivity analysis. These models enable the evaluation of pollutant reducers in terms of their environmental, economic, and social sustainability. The results reveal that the most suitable types of GR and PV are semi-intensive green roofs (SIGR) and building-attached photovoltaics (BAPV). This is while the quantitation analysis discloses that SIGR is capable of reducing 4.8 kg/m2 CO2 and 52.4 g/m2 Particulate Matter (PM), and BAPV has the potential of mitigating 211 kg/m2 CO2 and 1.2 g/m2 PM per year. Third, a compound alternative (CA), combining both GR and PV, is proposed as an optimal solution, effectively surmounting the individual shortcomings of these technologies. The optimization using mathematical patterns unveils more suitability of PV compared to GR for the case of Tehran. In this sense, the most effective combination ratio for the execution phase simplifies to 3:1 (PV:GR). Fourth, a synergistic strategy is adopted to consider optimized pollutant reducers and target buildings simultaneously. Using the Geographic Information System (GIS), the study recommends focusing on residential buildings of medium height in medium surface scale as the ideal targets. Fifth and finally, implementing the optimized CA on selected target buildings provides a significant potential to decrease over 9% of total PM and CO2 emissions from all sources and sectors across Tehran. Furthermore, the study reveals the prospect of transforming selected groups of residential buildings into Zero-PM buildings in the operational phase.This dissertation provides valuable insights into addressing rooftop-based air pollutant reducer technologies and also offers a systematic approach that can be adapted to various urban contexts. The developed framework, models, and proposed future works, can assist decision-makers in selecting the most appropriate strategies, contributing to cleaner, more sustainable, and resilient urban environments worldwide.Keywords: Climate change; Sustainability assessment; Urban air pollution; Residential buildings; Rooftops

Committee:
     PRESIDENT: DE MOURA FERREIRA DANILEVICZ, ANGELA
     SECRETARI: KAMPOUROPOULOS, KONSTANTINOS
     VOCAL: CÓSTOLA, DANIEL
Thesis abstract: The field of architecture and engineering is currently experiencing significant changes due to advances in technology and the growing role of Artificial Intelligence. This shift is largely driven by the growing urgency of promoting more efficient buildings, especially considering its substantial impact on global greenhouse gas emissions and energy usage. Consequently, it is becoming important to focus on practical design choices and utilize effective strategies to enhance energy efficiency and overall building performance. This thesis presents a comprehensive approach to optimize the shape, solar orientation, and envelope configuration of social residential buildings in a humid subtropical climate (Koppen classification: Cfa) in the southern region of Brazil. The main objective is to simultaneously minimize both heating and cooling demands, and present optimal performance design and parameter ranges to improve efficiency energy in multifamily buildings. To achieve this, the study utilizes multi-objective optimization techniques with the support of a non-dominated sorting genetic algorithm (NSGA-II). The simulations are conducted using the EnergyPlus while the optimization process is implemented through Python programming. This extensive computational effort involves a total of 480,000 simulations. The results of the optimization process demonstrate that by carefully selecting the optimal solar orientation, significant reductions in energy demand can be achieved. For instance, optimizing the solar orientation alone can lead to energy demand reductions of up to 5% for linear buildings and 11% for H buildings, when linked to the surroundings. Furthermore, when the envelope is properly addressed the energy demand between shapes achieves almost the same value. Moreover, the optimization of the building envelope configuration further enhances energy efficiency, resulting in remarkable reductions in total energy demand. In particular, linear buildings can achieve up to 60% reduction in energy demand, while H buildings reach up to 63% reduction. These findings highlight the potential benefits of considering solar orientation, surrounding shadows, and envelope design simultaneously during the early design stages of a project. The proposed three-phase optimization framework evaluates different parameter alternatives and presents a pratical guidelines to make informed decisions about the most energy-efficient configurations.

Committee:
     PRESIDENT NO PRESENCIAL: DELGADO MENDEZ, LUIS
     SECRETARI: DIAZ GOMEZ, CESAR
     VOCAL NO PRESENCIAL: CARDENAS HARO, XAVIER RICARDO
Thesis abstract: The present research is aimed at deepening the evaluation of adhesion in architectural tile coverings in the building sector; despite the improvement of new cementitious adhesives and new ceramic tiles, detachment failures still occur in tile coverings, which can be due to external forces (shocks, earthquakes, vibrations, etc.), inadequate prescription of the cementitious adhesive, incorrect installation, or lack of preparation of the substrate. How to recognize in an inspection the defective state of adhesion of a tiling of this type, in order to prevent detachment?At present, this adhesion is usually evaluated in the laboratory by means of destructive horizontal surface tensile testing systems described in the current regulations on cementitious adhesives. No non-destructive systems have been described for use on site in any layout. The objective of this research is to develop a non-destructive procedure for the evaluation of the state of adhesion of an architectural tiling that is of practical use at the construction site. Several existing alternative techniques, such as thermography or ultrasound, have been considered in the research, but finally it has been decided to focus on the analysis of the acoustic signal obtained by standardized percussion of a tiled tiling on site. This percussion technique has its antecedents in the traditional practice of the experienced architect who manually percussed the tiling with the knuckles of his hand and who, based on his experience, established the lack of adhesion as a defect associated with a "hollow and more vibrant" sound, compared to that of well-bonded tiles. Digital percussion recording analysis is a technique that is already being developed in the field of mechanics to assess the condition of fasteners.The methodology developed in this research is based on successive experimental campaigns in which the PhD student architect has been able to participate, evolving from the understanding of the different vibration phenomena of a free-standing tile depending on the support bonds, through the evaluation of the main vibration frequency of a percussive tiling to the analysis of the correlation between various proposed parameters related to energy, time and their frequency with respect to the values reached in standardized pull-off tests, before and after accelerated aging processes.It is concluded that the results achieved are very promising, although further work is needed to focus on how the acoustic signal emitted by the percussion is modified when it passes through not only the tile and the cementitious adhesive that binds it to the substrate, but especially when it passes through the contact interface between the two.

Committee:
     PRESIDENT: DE ANDRADE SILVA, FLAVIO
     SECRETARI: CORNADÓ BARDÓN, CÒSSIMA
     VOCAL: SANZ ARAUZ, DAVID
Thesis abstract: This thesis investigates the feasibility and potential applications of flax fiber-reinforced lime mortars in masonry construction, particularly focusing on the seismic retrofitting of Unreinforced Masonry (URM) buildings. The composite material, featuring a non-woven structure of flax fiber layers within the lime mortar matrix, undergoes a comprehensive examination with a specific emphasis on mechanical properties, durability, and consistency. Structured as a collection of articles, the thesis covers various dimensions to provide a holistic understanding of the material's capabilities and applications. The first article delves into the mechanical characterization of Flax Fiber Reinforced Lime Mortars. This involves a rigorous assessment of properties such as tensile strength, compressive strength, flexural strength, and toughness. These mechanical attributes are crucial for determining the material's structural integrity and its potential effectiveness in retrofitting applications.In addition to mechanical properties, the thesis explores the durability of flax fiber-reinforced lime mortars. Durability tests are designed to simulate long-term exposure to environmental conditions, including moisture, temperature changes, and other potential stressors. Evaluating the material's resistance to these factors is essential for ensuring its performance and longevity in real-world applications. An integral part of the research involves investigating the optimal configuration of flax fiber layers within the lime mortar. This aspect aims to optimize the composite's flexibility, crack resistance, and chemical compatibility with historic masonry materials. The layered composition is a critical consideration for achieving the desired structural enhancements while maintaining the material's compatibility with historical structures. Furthermore, the thesis contributes to the understanding of the adhesion between flax fiber-reinforced lime mortars and masonry materials. The adhesion characteristics play a pivotal role in determining the effectiveness of the material as a retrofitting solution for URM buildings. The study aims to provide valuable insights into the mechanical properties, durability, and adhesion to ensure a comprehensive understanding of the material's suitability for historical masonry structures.In conclusion, this research, encapsulated in a series of articles, offers a thorough exploration of flax fiber-reinforced lime mortars for masonry construction. The emphasis on mechanical properties, durability, and adhesion positions the material as a potential innovative solution for retrofitting URM buildings. This not only aligns with sustainability goals but also ensures the preservation of cultural heritage. Looking forward, the thesis provides a foundation for further research, suggesting avenues such as numerical modeling and additive manufacturing for a more nuanced understanding and practical application of the developed materials in the construction industry.

Committee:
     PRESIDENT: GRAUS ROVIRA, RAMON
     SECRETARI: CHAMORRO TRENADO, MIGUEL ÁNGEL
     VOCAL: VEGAS LOPEZ-MANZANARES, FERNANDO
Thesis abstract: In the area of architecture and construction, natural cement is the least known of traditional conglomerates. Most professionals in the sector who are interested in conglomerates have broad knowledge of the two types of lime and perhaps even of traditional plaster. However, they do not tend to be informed about natural cement. The aim of this thesis is to provide information about this type of cement in terms of how important its industry was in Catalonia and its meaning today. With this idea, we have organised the research into two parts. The first part provides a historical study of the material. It examines the first written references that reached us here, long before natural cement began to be manufactured, when and where the first natural cement was produced, how and where this industry spread around Catalonia, which types of natural cements were manufactured, their characteristics and properties, how and where they were manufactured, the first regulations governing the material, its uses, etc. This production was anonymous but relevant, with over a hundred and fifty years of history, from its beginnings in the mid-nineteenth century to the current time, spread out among various regions of Catalonia: Gironès, Alt Empordà, Ripollès and Berguedà, among many others. The second part, which we have called the present, is set from the transitory period of the civil war and postwar up to the study of natural cements that are manufactured today. A total of four quick-setting natural cements are examined. We have discovered their properties, characteristics, specific features, strengths and weaknesses.

Committee:
     PRESIDENT: WADEL RAINA, GERARDO FABIAN
     SECRETARI: ROSET CALZADA, JAIME
     VOCAL: ZABALZA BRIBIAN, IGNACIO
Thesis abstract: This research focuses on the study and comparative analysis of buildings constructed with industrialized prefabrication systems, based on the premise that industrialization implies resource optimization, technological innovation and environmental sustainability. Taking advantage of the European regulatory framework on the subject, the analysis will be based on the methodology of Life Cycle Assessment (LCA) in selected cases under parametric criteria. The methodology will also be applied to buildings in the Central American region, which does not yet have a consolidated framework for the regulation of environmental sustainability strategies, and which is ideal given the growing use of new industrialized technologies for construction in the region, immersed in a context of seismic hazards.The International Organization for Standardization (ISO) has developed a set of LCA standards that focus on the technical and organizational aspects of a building. However, pragmatically, the studies are conducted using different approaches and there is insufficient clarity as to whether their results are comparable or useful for decision making in the design process and subsequent building evaluation. Many authors agree that it is difficult to make meaningful comparisons between the results and, therefore, to draw conclusions to inform project decision making. There are allegedly several reasons for this, such as: methodological differences, discrepancies in the scope of the evaluation, data uncertainties, differences in location, and differences between units of analysis. However, in the present research, these barriers have been overcome largely by developing a calculation model with an open database that allows the same type of data to be entered for all cases, allowing comparative analysis and verification of the parameters that affect the carbon footprint throughout its life cycle. The data was also compared to the state of the art. To this end, this thesis is divided into three parts: Part I: Introduction, which includes chapters I through VI. Part II: State of the Art, which contains chapters 1 through 8. Part III: Analysis, which contains chapters 9, 10, and 11. As a whole, it represents a qualitative and quantitative research on environmental sustainability in buildings and its influencing parameters, among which; optimization, life extension, circularity and energy independence. Among the main findings, it can be stated that the decarbonization of the life cycle of a building, even without the optimization of the construction systems, can be carbon neutral in the operational phase, thanks to the surplus of renewable energy generation (photovoltaic) associated with sunlight, depending on the latitude, which is one third higher in the tropics than in the Mediterranean area.The initial hypothesis that industrialized prefabrication contributes to environmental sustainability is confirmed, despite the fact that specialized structural systems designed for disassembly require a high mechanical performance that can only be achieved through the hybridization of materials; their end-of-life recovery leads to an average reduction of 60% in the carbon footprint. On the other hand, the optimization of buildings can begin by reducing their weight, especially in the case of soils with low bearing capacity, since foundations can represent up to 50% of the embodied carbon, significantly influencing the total carbon footprint; moreover, since foundations are monolithic, their non-recovery at the end of the building's life results in the loss of raw materials. These facts lead to the important lesson of performing LCA before demolishing a building, rather than just at the beginning of the project.

Committee:
     PRESIDENT: ROSSELLO NICOLAU, MARÍA ISABEL
     SECRETARI: PAREJA EASTAWAY, MONTSERRAT
     VOCAL: ATZENI, CARLO
Thesis abstract: This thesis addresses the connections between housing and vulnerability by studying habitability in two of Barcelona’s most underprivileged neighbourhoods, as part of the debate on policies for housing rehabilitation and urban regeneration. Although there is a long tradition of increasingly multifaceted interventions it is still difficult to improve spatial conditions without leaving disadvantaged groups behind.This research is based on the idea that space plays an important role in socio-residential vulnerability and inequality, and that this role has not been studied sufficiently. An in-depth look grounded in the local context and conducted on a small scale can help to bridge the gap between the large-scale analyses provided by geographical socio-urban studies and the architectural analyses that generally guide the design and the implementation of rehabilitation programs.Our main goal is to analyse how spatial characteristics affect habitability in underprivileged areas, and to relate this with other structural factors of socio-residential vulnerability. We also hope to discuss the limitations and potential of rehabilitation polices in improving the living conditions of the most vulnerable neighbours.The study consists of an experimental analysis of housing conditions in four small underprivileged areas of Barcelona’s Besòs-Maresme and Raval neighbourhoods. With a focus on the smallest possible units of cohabitation (dwellings and common spaces), we carry out a multi-scalar approach based on extensive fieldwork to describe and evaluate residential spaces while taking into account the current inhabitants.The discussion on the role of space is addressed in three different ways:I. By analysing housing conditions and detecting the most common and severe shortcomings. This includes the description of their scale and opportunities for improvement.II. By detecting and locating critical cases and micro-inequities and describing their spatial and geographic distribution. III. By providing a context for these results in each sector in relation to morpho-typological characteristics, the history of public interventions, and non-spatial aspects such as forms of ownership and tenure or other sociodemographic and socioeconomic circumstances.The results of this study describe, localize and contextualize the general lack of adequate housing conditions and a significant proportion of critical cases in the studied areas. Particularly noteworthy are the lack of accessibility, environmental comfort and quality in interior shared spaces (common entryways, stairs and landings). Other severe deficiencies are more localized, like the insufficient dimension of interior and exterior spaces (both private and common). Micro-inequalities of different intensity are found in all areas, and they show spatial patterns that can only be observed by looking at the small scale: between neighbouring buildings or even dwellings. If we look beyond spatial and material characteristics, the lack of decent housing conditions, its scope and spatial distribution are related to other residential exclusion factors shaped by property, tenure and occupancy. Inadequate housing is closely tied to the lack of stable, affordable housing.This study highlights the need to address area-based interventions with a multifaceted and multi-scalar approach. These require coordinated polices that simultaneously address the improvement of residential spaces along with housing and social rights. Our conclusions confirm the significant role of spatial housing conditions along with socio-spatial and non-spatial aspects that must also be considered in any public interventions aimed at attaining a universal right to decent housing.