Simulation and comparative analysis of waste in concrete slabs

Construction sector generates significant amounts of waste that affects the environment and obstructs a sustainable development. The horizontal structure (slabs and roofs) is one of the building elements, by its functional requirement (geometry and layout) and volume, who uses more raw material for its constitution (potential generators of waste) On the other hand, the choice of the system to use, is typically based on criteria such as the ease of construction, the economy availability or the technological feasibility; so, from a sustainable perspective, the generation of waste has not been considered or evaluated. This work compares and analyzes four different common elements used in slabs and the possible generation of waste produced for the construction and eventual demolition of them, in order to provide a new weighting criterion in the choice.Peer ReviewedPostprint (published version

Simulation and comparative analysis of waste in concrete slabs

Construction sector generates significant amounts of waste that affects the environment and obsturcts a sustainable development. The horizontal structure (slabs and roofs) is one of the building elements, by its functional requirement (geometry and layout) and volume, who uses more raw material for its constitution (potential generators of waste) On the other hand, the choice of the system to use, is typically based on criteria such as the ease of construction, the economy availability or the tecnological feasibility; so, from a sustainable perspective, the generation of waste has not been considered or evaluated. This work compares and analyzes four different common elements used in slabs and the possible generation of waste produced for the construction and eventual demolition of them, in order to provide a new weighiting criterion in the choice.Peer ReviewedPostprint (published version

Assessment of the human health risks and toxicity associated to particles (PM10, PM2.5 and PM1), organic pollutants and metals around cement plants

Les partícules en suspensió (PM) són el contaminant aeri més perillós per a la salut humana. Aquestes es componen de partícules sòlides i líquides que floten a l’aire i que tenen mida i composició química diversa. Les PM solen classificar-se segons la seva mida. Així, aquelles que presenten un diàmetre menor de 10 micres es nomenen PM10, les menors de 2,5 micres es coneixen com PM2.5, i les menors de 1 micres es nomenen PM1. Una de les indústries tradicionalment reconegudes com a font de PM són les cimenteres. Encara que hi ha nombrosos estudis dedicats a les PM al voltant de cimenteres, aquests solen enfocar-se en les PM10, ignorant la importància d'aquelles més petites, i que poden arribar a zones més profundes de l'aparell respiratori. En la present tesi es van recollir PM10, PM2.5 i PM1 en una àrea influenciada per una cimentera durant diferents estacions. Posteriorment, es va dur a terme una caracterització fisicoquímica d'aquestes partícules, per estudiar els seus riscos inhalatoris i contribució de la cimentera al total de PM ambiental. A més, part d'aquestes partícules es van dedicar a fer assajos in-vitro amb cèl·lules respiratòries, per avaluar la seva toxicitat. Els majors nivells de PM es van registrar a l'hivern. A més, es va trobar que més del 60% de les partícules respirables són PM1. Aquesta última fracció va contenir els majors nivells d'alguns metalls pesats i hidrocarburs policíclics, presentant els majors riscos per a la població. Les proves in-vitro van revelar que la fracció fina (PM2.5) donava lloc a una toxicitat general més gran que les PM10. Finalment, la contribució de la cimentera al total de PM ambiental va resultar patent i dependent de l'estat productiu de la planta. Els resultats d'aquesta tesi mostren la importància d'estudiar les partícules fines (PM2.5 i PM1) en entorns influenciats per fàbriques de ciment.Las partículas en suspensión (PM) son el contaminante aéreo más peligroso para la salud humana. Éstas se componen de partículas sólidas y líquidas que flotan en el aire y que tienen tamaño y composición química diversa. Las PM suelen clasificarse según su tamaño. Así, aquellas que presentan un diámetro menor de 10 µm se nombran PM10, las menores de 2,5 µm se conocen como PM2.5, y las menores de 1 µm se nombran PM1. Una de las industrias tradicionalmente reconocidas como fuente de PM son las cementeras. Aunque hay numerosos estudios dedicados a las PM alrededor de cementeras, éstos suelen enfocarse en las PM10, ignorando la importancia de aquéllas más pequeñas, y que pueden llegar a zonas más profundas del aparato respiratorio. En la presente tesis se recogieron PM10, PM2.5 y PM1 en un área influenciada por una cementera en diferentes estaciones. Posteriormente, se llevó a cabo una caracterización fisicoquímica de estas partículas, para estudiar sus riesgos inhalatorios y contribución de la cementera al total de PM ambiental. Además, parte de estas partículas se dedicaron a hacer ensayos de in-vitro con células respiratorias, para evaluar su toxicidad. Los mayores niveles de PM se registraron en invierno. Además, se encontró que más del 60% de las partículas respirables son PM1. Esta última fracción contuvo los mayores niveles de algunos metales pesados e hidrocarburos policíclicos, presentando los mayores riesgos para la población. Las pruebas in-vitro revelaron que la fracción fina (PM2.5) daba lugar a una toxicidad general mayor que las PM10. Por último, la contribución de la cementera al total de PM ambiental resultó patente y dependiente del estado productivo de la planta. Los resultados de esta tesis muestran la importancia de estudiar las partículas finas (PM2.5 y PM1) en entornos influenciados por fábricas de cemento.Particulate matter (PM) is the most dangerous air pollutant for human health. Particulate matter is composed of solid and liquid particles floating in the air and having different size and chemical composition. PMs are usually classified according to their size. Thus, those with a diameter smaller than 10 μm are named PM10, those smaller than 2.5 μm are known as PM2.5, and those smaller than 1 μm are referred as PM1. Cement plants are one of the industries traditionally recognized as sources of PM. Although there are numerous studies dedicated to PM around cement factories, they tend to focus on PM10, ignoring the importance of smaller PM, which can reach deeper areas of the respiratory system. In the present thesis PM10, PM2.5 and PM1 were collected in an area influenced by a cement plant in different seasons. Subsequently, a physicochemical characterization of these particles was carried out to study their inhalation risks and the cement plant's contribution to the total environmental PM. In addition, to evaluate their toxicity part of these particles was dedicated to performing in-vitro tests with respiratory cells. The highest PM levels were recorded in winter. In addition, it was found that more than 60% of the respirable particles are PM1. This last fraction contained the highest levels of some heavy metals and polycyclic hydrocarbons, presenting the greatest risks for the population. In-vitro tests revealed that the fine fraction (PM2.5) resulted in a higher overall toxicity than PM10. Finally, the contribution of the cement company to the total environmental PM was clear and dependent on the productive state of the plant. The results of this thesis highlight the importance of studying fine particles (PM2.5 and PM1) in environments influenced by cement factories

Implementation of Interaction Diagram of the Properties in Fresh for Mortars with Ceramic Aggregates

As the natural resources needed for the construction sector arelimited, new practices are being adopted for the managementof waste generated nowadays, including the use of constructionand demolition waste as aggregates for concrete and mortar.Considering the different typologies in construction wastes,ceramics are the second most representative material; thereforeit is important to validate their feasibility as a total orpartial replacement of natural aggregates. This work presentsa study of the properties in fresh state (consistency, density andair content) of mortars containing aggregates obtained fromrecycled ceramics, and their influence on the subsequent propertiesin the hardened state. A statistical analysis of experimentaldata was carried out by establishing regression coefficients,and then a triple-entry graph was obtained, allowing the differentproperties of mortars to be easily linked and simplifyingthe prediction of the relationships they will present since themixture design phase.

Characterization of three recycled materials for alternative use of mortars

Because natural resources in construction are limited, it is advisable to look for new alternatives that meet comparable functions, and likewise, reduce consumption of non-renewable resources. The use of recycled materials is of benefit to the uncontrolled eliminations of residues that cause the use of the public resources, such as landfills. In addition, this contributes to the reduction of the environmental imact caused by the industries in the process of obtaining the same ones. Therefore, recycled materials such as concrete or masonry demolished, glass and ceramics different, can be employed in different ways to be used in the construction industry. This work focuses on presenting the initial characterization of three reveled materials as an alternative to use in relacement of natuals sand in mortars, this as a first step for furher study in different percentages of replacement, as currently his inderstanding is unknown, or little known.Peer ReviewedPostprint (published version

Psychometric analysis in knowledge-evaluation questionnaires, identification and implication

The experience achieved using the tool “Questionnaires”, available inside the Virtual Campus of architectural engineering school in northeast Spain, is presented. “Questionnaires” is an adequate and simple instrument to evaluate the knowledge level achieved by students. This work shows and identifies the control indices of adaptation for the questionnaires, like the Facility Index, the Standard Deviation, the Discrimination Index and the Discrimination Coefficient. Derived from these parameters, the educational performances are inferred, identified and predicted. The conclusions of this work, permit to modify deficient knowledge-evaluation practices, to identify needs for specific groups or for students with particular requirements; being, in this way, feasible to apply these parameters with guarantee of success in similar evaluation processesPostprint (published version

Propiedades en estado fresco de morteros con árido reciclado de hormigón y efecto de la relación c/a

Los residuos de construcción y demolición se han convertido en un problema urbano que resulta complejo y de un alto coste de gestión. Por este motivo, en la actualidad se está innovando en legislación medioambiental para fomentar diferentes actividades que lo mitiguen; siendo el reciclado una de las más aptas (faculta su reinserción como material de segunda generación para su nuevo uso en la construcción). En esta dirección se han realizado varios estudios de morteros en los que los residuos sustituyen diferentes porcentajes de los áridos naturales, a falta de una legislación propia que marque pautas de combinación. Sin embargo, poco se ha indagado en el comportamiento de su estado en fresco, el cual es vinculado con sus propiedades en estado endurecido a posteriori. En esta investigación se han realizado ensayos de propiedades en estado fresco (consistencia, densidad y contenido de aire) de morteros que contienen diferentes porcentajes de sustitución de áridos naturales, remplazados por áridos de hormigón reciclado (10, 20, 30, 50 y 100 %) a diferentes relaciones de cemento/arena (1:3.25, 1:4 y 1:4.74). Los resultados obtenidos muestran que los morteros con áridos reciclados reportan menor densidad, necesitan mayor cantidad de agua para lograr la consistencia requerida y presentan mayor contenido de aire que los morteros de referencia, sin sustitución de áridos reciclados.Peer ReviewedPostprint (published version

Dielectric and electrochemical properties of sustainable concrete

It is planned to improve the durability of reinforced concrete structures and the total or partial replacement of their components by the use of recyclable materials; as strategies to contribute to the concrete industry sustainability. The electrical resistivity and its relationship with the microstructure and electrochemical corrosion resistance in reinforced concrete manufactured with sustainable characteristics, that is, with recycled aggregates and supplementary cementitious materials; was evaluated in this study. The electrical resistivity in reinforced concretes is closely related to the microstructure of the cementitious matrix, and with the pore structure and distribution. As a consequence of the their components nature, it is assumed that the proposed sustainable concretes present different microstructure and porosity than the conventional concretes; because of this, the electrical and electrochemical response of those systems was analyzed with the help of the electrochemical impedance spectroscopy technique.Postprint (published version

Metamorphosis in the porosity of recycled concretes through the use of a recycled polyethylene terephthalate (PET) additive. Correlations between the porous network and concrete properties

In the field of construction, sustainable building materials are currently undergoing a process of technological development. This study aims to contribute to understanding the behavior of the fundamental properties of concretes prepared with recycled coarse aggregates that incorporate a polyethylene terephthalate (PET)-based additive in their matrix (produced by synthesis and glycolysis of recycled PET bottles) in an attempt to reduce their high porosity. Techniques to measure the gas adsorption, water porosity, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to evaluate the effect of the additive on the physical, mechanical and microstructural properties of these concretes. Porosity reductions of up to 30.60% are achieved with the addition of 1%, 3%, 4%, 5%, 7% and 9% of the additive, defining a new state in the behavioral model of the additive (the overdosage point) in the concrete matrix; in addition, the porous network of these concretes and their correlation with other physical and mechanical properties are also explained.Peer ReviewedPostprint (published version

Integrating dual C and N isotopic approach to elemental and mathematical solutions for improving the PM source apportionment in complex urban and industrial cities: Case of Tarragona - Spain

Identification of dominant airborne Particulate Matter (PM) sources is essential for maintaining high air quality standards and thus ensuring a good public health. In this study, different approaches were applied for source apportionment of three PM fractions (PM1, PM2.5 and PM10) at the outdoor of 14 schools of a coastal city with a significant land use interweaving such as Tarragona (Spain). PM were collected in 24h-quartz microfiber filters in two seasonal campaigns (cold and warm), together with nine local potential sources, so a total of 84 samples were chemically, mineralogically, and isotopically characterised. Source apportionment was assessed by (i) main chemical components, (ii) Principal Component Analysis (PCA), (iii) dual C and N isotope approach, and (iv) a Bayesian isotope mixing model. When chemical concentrations were grouped into marine, crustal, secondary inorganic aerosols and organic matter + elemental carbon categories, the unaccounted component reached 45% of PM mass. The PCA allowed to identify also traffic and industrial contributions, reducing the unaccounted mass to about 25%. Adding δ13C and δ15N values, secondary organic aerosol could be estimated and a continuous contribution of diesel combustion was identified together with a remarkable use of natural gas in winter. Isotopic values were better understood when considering air masses back trajectories and a possible long-distance contribution from coal-fired electric generating units (EGUs). Finally, using Bayesian dual isotope mixing models, the unaccounted PM mass was reduced up to 5% when adding these EGUs to marine-carbonate related, road traffic, domestic heating, waste incinerator and livestock waste contributions. The added value of the dual isotope approach combined with a Bayesian isotope mixing model, in comparison with conventional chemical approaches, was thus demonstrated for PM source apportionment in an urban and industrial site where many sources and processes converge and can then be applied to other complex cities