Thesis (Ph. D.)--Institute of Paper Chemistry, 1943. / Includes bibliographical references (p. 84-85).

Μελετάται η ανάπτυξη μεθόδου για την εις βάθος συσσωμάτωση χαλαρών εδαφών που προορίζονται για οικοδόμηση καθώς και για εδάφη περιοχών που υποφέρουν από κατολισθήσεις. Με την ίδια κατά βάση μεθοδολογία, επιχειρείται η επίτευξη στεγανοποίησης κατασκευών σκυροδέματος που υποφέρουν από διαρροές ή από υγρασία και είναι αναγκαία η άμεση αποκατάσταση τους με χαμηλό κόστος. Και στις δύο περιπτώσεις η νέα μεθοδολογία αποτελεί καινοτομία φιλική στο περιβάλλον. Για το σκοπό αυτό προτάθηκε ένα σύστημα υδατοδιαλυτών χημικών με σκοπό την επί τόπου καταβύθιση ενός δυσδιάλυτου άλατος στα τοιχώματα των πόρων του σκυροδέματος και την μείωση της υδατοπερατότητας του υλικού. Το προτεινόμενο άλας ήταν το οξαλικό ασβέστιο (CaC2O4). Το οξαλικό ασβέστιο είναι το κύριο συστατικό των λίθων του ουροποιητικού. Το μονοένυδρο και διένυδρο οξαλικό ασβέστιο έχουν ανιχνευθεί στην πατίνα, το επιφανειακό επίστρωμα που έχει σχηματιστεί σε αρχαία μνημεία, αγάλματα και φυσικά σχηματισμένους βράχους. Μέχρι σήμερα θεωρείται ότι το στρώμα αυτό οξαλικού ασβεστίου στην επιφάνεια των αρχαίων μνημείων, παίζει σημαντικό προστατευτικό ρόλο για την επιφάνεια που καλύπτει. Αρχικά έγινε συστηματική μελέτη της αυθόρμητης καταβύθισης του οξαλικού ασβεστίου σε αντιδραστήρες διαλείποντος έργου. Οι πειραματικές συνθήκες ήταν τέτοιες που να προσομοιάζουν τις συνθήκες κατά την εφαρμογή των χημικών στο σκυρόδεμα (θερμοκρασία 25°C, pH=6.5 και 10). Μελετήθηκε η επίδραση συνθετικών κρυστάλλων μονοένυδρου οξαλικού ασβεστίου (COM) και κόκκων τσιμεντοκονιάματος. Σε όλες τις περιπτώσεις ανιχνεύθηκε το COM στην καταβυθιζόμενη φάση. Οι κρύσταλλοι αναπτύσσονται πάνω στους κόκκους τους τσιμεντοκονιάματος και σχηματίζουν μεγάλα συσσωματώματα. Το μέγεθός τους (8-10 μm) και το σχήμα τους (εξαγωνικό πρισματικό) είναι χαρακτηριστικά που ευνοούν το οξαλικό ασβέστιο να παίξει το ρόλο συνδετικού υλικού σε πορώδη μέσα. Ο κύριος μηχανισμός κρυσταλλικής ανάπτυξης είναι η επιφανειακή διάχυση των δομικών μονάδων στην επιφάνεια του κρυστάλλου. Τέλος, μελετήθηκε η επί τόπου καταβύθιση του COM σε δοκίμια τσιμεντοκονιάματος. Τα διαλύματα εισέρχονταν στο εσωτερικό του δοκιμίου με τη βοήθεια της βαρύτητας. Στα δοκίμια τσιμεντοκονιάματος πραγματοποιήθηκαν πειράματα τριχοειδούς εισρόφησης νερού και μηχανικής επιφανειακής απότριψης. Κατεργασία του τσιμεντοκονιάματος με διάλυμα οξαλικού νατρίου σε υψηλές θερμοκρασίες, φαίνεται να μειώνει την εισρόφηση του νερού. / A new environmental friendly method, for the stabilization of loose soils to be used as building sites and for the amelioration of the properties of concrete constructions suffering from water leaks or humidity has been developed. The novelty of the proposed method is lying on the in situ precipitation of calcium oxalate monohydrate (COM) within the porous structure of soil or on the pore walls of the construction material (concrete) in order to minimize water leakage. Calcium oxalate, encountered often in kidney stones in the form of COM, is notorious for the formation of hard, non-porous aggregates which adhere tenaciously onto substrates. Calcium oxalate in the form of a protective patina is often met as surface layer in marbles or limestones. Mechanistic information concerning the formation of COM in supersaturated solutions may be obtained in seeded growth experiments. In these experiments, supersaturated solutions are seeded either with seed crystals of the same under investigation salt or of any other insoluble solid material on which the heterogeneous formation of the salt of interest may take place. Among the objectives of the present work was to investigate the role of concrete grains on the nucleation and crystal growth of COM. The analysis of the kinetics data showed that the prevalent mechanism for COM precipitation was surface diffusion. In all cases the only crystalline phase forming in the supersaturated solutions was identified as COM. In the second part of the present work the in situ precipitation of COM into mortar samples was studied. SEM analysis showed that crystallization indeed took place within the pores of the concrete. Best results in terms of waterproofing of concrete material were obtained in the case of treating concrete surfaces with sodium oxalate solution at high temperature.

O estudo do colagênio na pele sobre sua estrutura e propriedades, composição e interações com substâncias levam a um maior entendimento das alterações químicas, micro e macroscópicas que ocorrem durante o processo de produção do couro. No processamento do couro são realizadas várias etapas que promovem a alteração da estrutura dérmica da pele, como acontece no acabamento molhado, onde reações químicas com a molécula de colagênio curtido são realizadas pela adição de produtos químicos, como recurtentes e óleos de engraxe, influenciando na estrutura macroscópica final, e ainda, dando propriedades específicas para o produto final, conforme a aplicação do couro. O acabamento final tem o objetivo de agregar valor ao artigo de couro, e as interações dos produtos aplicados sobre o couro nas camadas mais externas da estrutura que acontecem nesta etapa são determinantes quanto à qualidade do couro que se quer obter e suas propriedades, inclusive na parte estética e funcional. Ainda, durante seu processamento, o couro mantém propriedades importantes da estrutura fibrosa formada pelo colagênio, sendo este o principal motivo do couro, como produto industrializado, apresentar propriedades únicas e particulares, fazendo dele um material de vasta aplicação e de alto valor agregado. Neste trabalho, foram feitas determinações para comparar formulações de engraxe para couro estofamento automotivo (uma para couro hidrofugado e outra não), e verificar a influência dessas formulações utilizadas sobre as propriedades dos couros em estágio de processo wet-blue, semi-acabado e após aplicação de acabamento. Ainda, na determinação de propriedades, foi estudada a influência do local de retirada da amostra no couro nos experimentos realizadas com repetição em couros distintos, duplicata para três regiões do couro, e para cada etapa do processo. Para comparação entre as formulações, os couros utilizados foram meio gêmeos, usando o mesmo critério da região do couro. As variáveis de resposta de propriedades dos couros assim obtidos foram baseadas nas análises de resistência mecânica, caracterizações químicas e absorção de água, e ainda para evidenciar a modificação da estrutura do couro foram feitas análises de MEV (microscopia eletrônica de varredura) e superfície interna pelo método BET. Os resultados indicam que as técnicas analíticas utilizadas mostram reprodutibilidade para os diferentes couros testados, quando comparados região a região, uma vez que os resultados indicam que existe forte tendência da retirada do local de amostragem conforme experimento por regiões do couro, ficando assim indicado que em trabalhos futuros, essa variável seja controlada. Conforme esperado, o couro hidrofugado teve menor absorção de água do que o couro apenas engraxado, devido à sua menor área superficial, evidenciado pelo MEV e BET. O estágio de processo teve maior influência nos resultados dos testes físicos. As caracterizações químicas serviram para evidenciar as diferenças entre o couro wet-blue e os couros acabados de maneira geral. / The study of changes in collagen from the hide related to its structure, properties and chemical interactions should be accompanied during the process of leather production. In the processing of leather, some stages are carried out promoting changes on the dermic structure of the hide, as it happens in wet-finishing stage, where chemical reactions happen into collagen molecules by the addition of chemical products, as re-tanning agents and fatliquors, influencing the final macroscopic structure and still giving specific properties for the finished leather according to its application. The finishing stage has the objective to add value to the leather article, and the interactions of products applied on the leather in external layers of the structure are determinative to the desired quality and properties of the leather, as well to the aesthetic and other functions. Still during its processing, the leather keeps important properties by the structure of the fibers formed of collagen, being this the main reason of the leather, as industrialized product, to present particular properties and making of it a material of vast application and high aggregate value. In this work, analyses are made to compare formulations of fatliquoring and hidrofugation for automotive leather in order to verify the influence of these on the properties of leathers in stages of wet-blue, crust and finishing. Moreover, the influence of the region of withdrawal of the sample from the hide was studied with repetition in distinct leathers. Still, the determination of properties, we studied the influence of local removal of the leather sample in the experiments performed with repetition in different leathers, duplicate for three regions of leather, and for each process step. For comparison between the formulations, the leathers used were half twins, using the same criteria in the region of the leather. The response variables of the properties of leather thus obtained were based on analysis of mechanical strength, chemical characterization and water absorption, and also to highlight the changed structure of the leather were analyzed by SEM (scanning electron microscopy) and the inner surface the BET method. The results indicate that the analytical techniques used to show the reproducibility of different leathers tested compared region by region, since the results indicate a strong trend of withdrawal of the sampling location as experiment by regions of the leather, thus indicated that in future work, this variable is controlled. As expected, the “waterproofing” leather, had lower water absorption than the oiled leather only because of its smaller surface area, as evidenced by SEM and BET. The stage of the process had a greater influence on the results of physical tests. The chemical characterization served to highlight the differences between the wet blue leather and finished leather in general.

O porongo (Lagenaria siceraria) é o fruto de uma planta da família das cucurbitáceas que quando colhido, se deixado secar, torna-se oco com o mesocarpo similar ao aspecto da madeira e o exocarpo liso e impermeável. Este fruto disseminou-se por todos os continentes antes do homem e foi uma das primeiras plantas domesticadas. Diferentes povos utilizam o porongo na confecção de recipientes, instrumentos musicais, boias e máscaras. No sul do Brasil é empregado na fabricação das cuias, recipientes para o chimarrão. Planta de hábito tropical, adapta-se facilmente à qualquer clima, com ciclo produtivo anual configura-se em alternativa de fonte renovável. Como material natural orgânico, é suscetível à degradação sem tratamento. Buscando viabilizar sua utilização na fabricação de recipientes para alimentos e bebidas priorizou-se a caracterização da estrutura e a aplicação de técnicas de impermeabilização. Para a confecção da amostras foram utilizados frutos coletados em Santa Maria, RS, e para a impermeabilização foi utilizada resina poliuretana à base de óleo de mamona. A caracterização do material constituinte do porongo foi feita com auxílio de microscópio eletrônico de varredura, microscopio de luz transmitida, análise termogravimétrica, determinação do teor de umidade, da densidade básica e da aparente e através da digitalização tridimensional para análise da variação dimensional. A caracterização da resina foi feita por espectroscopia de infra-vermelho com transformada de Fourier e a eficiência da impermeabilização foi analisada através de ensaio de absorção de água e ângulo de contato de gota. Pela microscopia identificou-se o exocarpo como uma fina camada de células compactas, por isso impermeável, e o mesocarpo formado pelo parênquima, com células que aumentam de tamanho progressivamente em direção ao centro, caracterizadas por grandes espaços vazios com parede espessada lignificada e canais de comunicação intercelular, que faz o material ser altamente hidrofílico. Ao absorver a água, há o preenchimento dos vácuolos das células até a saturação, sem grandes alteraçãos das dimensões do material, dimensionalmente estável. O porongo possui densidade heterogênea muito baixa, em média 0,124 g/cm³, na faixa de densidade das espumas poliméricas. Quanto à absorção de água, as amostras sem tratamento tiveram aumento de massa de cerca de 150% até a saturação. Após a impermeabilização, as amostras com uma camada de resina tiveram aumento de massa entre 23% e 37%, enquanto que àquelas com duas camadas de resina de apenas 5% e 6%, o que indica a eficiência do método de impermeabilização. / The bottle gourd (Lagenaria siceraria) is the fruit of the Cucurbitaceae family plant which when harvested, if allowed to dry, becomes hollow with the mesocarp similar to the appearance of the wood and with a smooth and impermeable exocarp. This fruit has spread to all continents before man and was one of the first domesticated plants. Different people use the gourd in the manufacture of containers, musical instruments, floats and masks. In southern Brazil it is used to manufacture the bowls, containers for mate. Tropical habit plant, easily adapts to any climate, with annual production cycle sets itself as renewable source alternative. As an organic natural material, it is susceptible to degradation without treatment. Seeking to enable its use in the manufacture of containers for food and beverages it has prioritized the characterization of the structure and the application of waterproofing techniques. Seeking allow its use in the manufacture of containers for food and beverages prioritized the characterization of the structure and the application of waterproofing techniques. To prepare the samples were used fruits collected in Santa Maria, RS, and for waterproofing was used polyurethane resin on castor oil base. The characterization of the material which constitutes porongo was made thorugh electron microscope scanning, transmitted light microscope, thermal analysis, determination of moisture content, basic and apparent density and by three-dimensional scanning to analyze the dimensional variation. The characterization of resin was made by infrared spectroscopy with Fourier transform and the efficiency of the waterproofing was analyzed by water absorption and drop contact angle test. Microscopy enabled to identify the exocarp as a thin layer of compact cells, thus waterproof, and the mesocarp formed by parenchyma with cells that progressively increase in size towards the center, characterized by large empty spaces with thickened and lignified wall and intercellular communication channels, which makes the material be highly hydrophilic. By absorbing the water, there is filling in the vacuoles of the cells until the saturation without large re-arranging of the material dimensions, dimensionally stable. The gourd has very poor heterogeneous density, on average 0.124 g / cm³, in the density range of polymeric foams. Regarding to water-absorbing, untreated samples had mass increase of about 150% until saturation. After sealing, the samples with a resin layer had increased mass between 23% and 37%, while those with two resin layers only had increased mass from 5% to 6%, which indicates the sealing method efficiency.

Denna rapport har kommit till efter en studie som genomförts för att försöka identifiera de viktigaste faktorerna som påverkar valet av slitlager på broar. Studien syftade även till att försöka bringa klarhet över vilka grunder som slitlager tidigare har valts på och bör väljas på i framtiden. Resultatet av studien är att slitlager riskeras att baseras på oklara grunder utan en tydlig motivering och otydliga riktlinjer. Det är ofta som personliga åsikter har ett stort inflytande i valet av slitlager. Ekonomi, typ av entreprenad eller estetik är andra avgörande faktorer vid val av slitlager. Studien har genomförts utifrån djupgående intervjuer med sakkunniga personer. / This report is the result of a study conducted to try to identify the most important factors affecting the choice of surface course on bridges. The study also aimed to clarify the reasons for which surface course were previously chosen and should be chosen in the future. The result of the study is that the surface course are likely to be chosen on unclear grounds without a clear motivation and unclear guidelines. It is often that private opinions have a big influence on the choice of the surface course. Economics, type of contract or aesthetics are other crucial factors in choosing of the surface course. The study has been conducted using in-depth interviews with people having knowledge in the field.

Orientador: Fabiano Tomazini da Conceição / Banca: Regina Célia de Oliveira / Banca: Sérgio dos Anjos Ferreira Pinto / Resumo: Nos estudos sobre o impacto das atividades antrópicas sobre o ambiente, têm-se a urbanização como uma das formas mais intensas de interferência na cobertura de superfície e alteração da dinâmica do escoamento superficial. No processo de uso e ocupação da terra, que contextualiza a formação das cidades, as populações comumente se fixavam às margens dos rios, e com o crescimento destes centros urbanos e o acréscimo de áreas impermeabilizadas houve a supressão das áreas de várzea, ocasionando situações de inundação. Em ambiente natural, as enchentes sempre fizeram parte da dinâmica natural do ciclo hidrológico. A impermeabilização da superfície, intensificada no Brasil principalmente a partir do crescimento das cidades na década de 70, gerou ao mesmo tempo a diminuição da capacidade de infiltração, o aumento do volume e da velocidade do escoamento superficial e a antecipação dos picos de cheias, provocando inundações mesmo em áreas que, em condições naturais, não apresentavam predisposição a tais eventos. À luz da Teoria dos Sistemas, partese da premissa de que a ocupação antrópica, sobretudo sob a forma de urbanização, interfere nas condições naturais do comportamento de uma bacia hidrográfica. Este trabalho objetivou caracterizar e avaliar as condições de drenagem na cidade de Rio Claro (SP), em diferentes cenários de ocupação urbana, considerando a bacia hidrográfica do Córrego da Servidão como unidade de análise. Por meio dos métodos do SCS (1986) - Soil Conservation Service foram avaliados os efeitos criados pela ocupação urbana no escoamento superficial em cenários de pré-canalização do córrego (1958), quando o córrego foi canalizado (1972), e no cenário atual (2006). As simulações hidráulicas e hidrológicas, implementadas no software IPHS1, foram utilizadas para... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the studies about the impact of human activities in the natural environment, urbanization is one of the most intense forms of interference in the surface coverage and changes in runoff. Concerning the use of land, which contextualizes the cities formation, the populations were fixed next to the rivers, and the increase of impermeable areas caused the suppression of floodplain, changing the river's dynamics and therefore causing flooding situations. In natural environments, floods have always been part of the natural dynamics of the hydrological cycle. The surface sealing, intensified in Brazil mainly through the growth of cities in the 70's, led to a reduced infiltration capacity, an increased volume and velocity of runoff, and an anticipation of floods, causing flooding even in areas that, in natural conditions, had no predisposition to such events. From the premise that human occupation interferes in the natural conditions of watersheds, this work aimed at characterizing and evaluating the drainage conditions in the city of Rio Claro (SP) in different sceneries of urbanization, considering the watershed of the stream of Servidão as the unit of analysis. The SCS method (1986) - Soil Conservation Service was used to evaluate the effects created by the urban occupation in the scenery before the channeling of the stream (1958), in a scenery where the stream was channeled (1972), and the current one (2006). The hydrological simulations, implemented in the software IPHS1 according to the different rainfall events, were used as a way to understand the variables related to flood situations. From the perspective of the evolution of urban occupation, the evaluation of the drainage behavior was held to sum reflections and... (Complete abstract click electronic access below) / Mestre

O estudo do colagênio na pele sobre sua estrutura e propriedades, composição e interações com substâncias levam a um maior entendimento das alterações químicas, micro e macroscópicas que ocorrem durante o processo de produção do couro. No processamento do couro são realizadas várias etapas que promovem a alteração da estrutura dérmica da pele, como acontece no acabamento molhado, onde reações químicas com a molécula de colagênio curtido são realizadas pela adição de produtos químicos, como recurtentes e óleos de engraxe, influenciando na estrutura macroscópica final, e ainda, dando propriedades específicas para o produto final, conforme a aplicação do couro. O acabamento final tem o objetivo de agregar valor ao artigo de couro, e as interações dos produtos aplicados sobre o couro nas camadas mais externas da estrutura que acontecem nesta etapa são determinantes quanto à qualidade do couro que se quer obter e suas propriedades, inclusive na parte estética e funcional. Ainda, durante seu processamento, o couro mantém propriedades importantes da estrutura fibrosa formada pelo colagênio, sendo este o principal motivo do couro, como produto industrializado, apresentar propriedades únicas e particulares, fazendo dele um material de vasta aplicação e de alto valor agregado. Neste trabalho, foram feitas determinações para comparar formulações de engraxe para couro estofamento automotivo (uma para couro hidrofugado e outra não), e verificar a influência dessas formulações utilizadas sobre as propriedades dos couros em estágio de processo wet-blue, semi-acabado e após aplicação de acabamento. Ainda, na determinação de propriedades, foi estudada a influência do local de retirada da amostra no couro nos experimentos realizadas com repetição em couros distintos, duplicata para três regiões do couro, e para cada etapa do processo. Para comparação entre as formulações, os couros utilizados foram meio gêmeos, usando o mesmo critério da região do couro. As variáveis de resposta de propriedades dos couros assim obtidos foram baseadas nas análises de resistência mecânica, caracterizações químicas e absorção de água, e ainda para evidenciar a modificação da estrutura do couro foram feitas análises de MEV (microscopia eletrônica de varredura) e superfície interna pelo método BET. Os resultados indicam que as técnicas analíticas utilizadas mostram reprodutibilidade para os diferentes couros testados, quando comparados região a região, uma vez que os resultados indicam que existe forte tendência da retirada do local de amostragem conforme experimento por regiões do couro, ficando assim indicado que em trabalhos futuros, essa variável seja controlada. Conforme esperado, o couro hidrofugado teve menor absorção de água do que o couro apenas engraxado, devido à sua menor área superficial, evidenciado pelo MEV e BET. O estágio de processo teve maior influência nos resultados dos testes físicos. As caracterizações químicas serviram para evidenciar as diferenças entre o couro wet-blue e os couros acabados de maneira geral. / The study of changes in collagen from the hide related to its structure, properties and chemical interactions should be accompanied during the process of leather production. In the processing of leather, some stages are carried out promoting changes on the dermic structure of the hide, as it happens in wet-finishing stage, where chemical reactions happen into collagen molecules by the addition of chemical products, as re-tanning agents and fatliquors, influencing the final macroscopic structure and still giving specific properties for the finished leather according to its application. The finishing stage has the objective to add value to the leather article, and the interactions of products applied on the leather in external layers of the structure are determinative to the desired quality and properties of the leather, as well to the aesthetic and other functions. Still during its processing, the leather keeps important properties by the structure of the fibers formed of collagen, being this the main reason of the leather, as industrialized product, to present particular properties and making of it a material of vast application and high aggregate value. In this work, analyses are made to compare formulations of fatliquoring and hidrofugation for automotive leather in order to verify the influence of these on the properties of leathers in stages of wet-blue, crust and finishing. Moreover, the influence of the region of withdrawal of the sample from the hide was studied with repetition in distinct leathers. Still, the determination of properties, we studied the influence of local removal of the leather sample in the experiments performed with repetition in different leathers, duplicate for three regions of leather, and for each process step. For comparison between the formulations, the leathers used were half twins, using the same criteria in the region of the leather. The response variables of the properties of leather thus obtained were based on analysis of mechanical strength, chemical characterization and water absorption, and also to highlight the changed structure of the leather were analyzed by SEM (scanning electron microscopy) and the inner surface the BET method. The results indicate that the analytical techniques used to show the reproducibility of different leathers tested compared region by region, since the results indicate a strong trend of withdrawal of the sampling location as experiment by regions of the leather, thus indicated that in future work, this variable is controlled. As expected, the “waterproofing” leather, had lower water absorption than the oiled leather only because of its smaller surface area, as evidenced by SEM and BET. The stage of the process had a greater influence on the results of physical tests. The chemical characterization served to highlight the differences between the wet blue leather and finished leather in general.

O porongo (Lagenaria siceraria) é o fruto de uma planta da família das cucurbitáceas que quando colhido, se deixado secar, torna-se oco com o mesocarpo similar ao aspecto da madeira e o exocarpo liso e impermeável. Este fruto disseminou-se por todos os continentes antes do homem e foi uma das primeiras plantas domesticadas. Diferentes povos utilizam o porongo na confecção de recipientes, instrumentos musicais, boias e máscaras. No sul do Brasil é empregado na fabricação das cuias, recipientes para o chimarrão. Planta de hábito tropical, adapta-se facilmente à qualquer clima, com ciclo produtivo anual configura-se em alternativa de fonte renovável. Como material natural orgânico, é suscetível à degradação sem tratamento. Buscando viabilizar sua utilização na fabricação de recipientes para alimentos e bebidas priorizou-se a caracterização da estrutura e a aplicação de técnicas de impermeabilização. Para a confecção da amostras foram utilizados frutos coletados em Santa Maria, RS, e para a impermeabilização foi utilizada resina poliuretana à base de óleo de mamona. A caracterização do material constituinte do porongo foi feita com auxílio de microscópio eletrônico de varredura, microscopio de luz transmitida, análise termogravimétrica, determinação do teor de umidade, da densidade básica e da aparente e através da digitalização tridimensional para análise da variação dimensional. A caracterização da resina foi feita por espectroscopia de infra-vermelho com transformada de Fourier e a eficiência da impermeabilização foi analisada através de ensaio de absorção de água e ângulo de contato de gota. Pela microscopia identificou-se o exocarpo como uma fina camada de células compactas, por isso impermeável, e o mesocarpo formado pelo parênquima, com células que aumentam de tamanho progressivamente em direção ao centro, caracterizadas por grandes espaços vazios com parede espessada lignificada e canais de comunicação intercelular, que faz o material ser altamente hidrofílico. Ao absorver a água, há o preenchimento dos vácuolos das células até a saturação, sem grandes alteraçãos das dimensões do material, dimensionalmente estável. O porongo possui densidade heterogênea muito baixa, em média 0,124 g/cm³, na faixa de densidade das espumas poliméricas. Quanto à absorção de água, as amostras sem tratamento tiveram aumento de massa de cerca de 150% até a saturação. Após a impermeabilização, as amostras com uma camada de resina tiveram aumento de massa entre 23% e 37%, enquanto que àquelas com duas camadas de resina de apenas 5% e 6%, o que indica a eficiência do método de impermeabilização. / The bottle gourd (Lagenaria siceraria) is the fruit of the Cucurbitaceae family plant which when harvested, if allowed to dry, becomes hollow with the mesocarp similar to the appearance of the wood and with a smooth and impermeable exocarp. This fruit has spread to all continents before man and was one of the first domesticated plants. Different people use the gourd in the manufacture of containers, musical instruments, floats and masks. In southern Brazil it is used to manufacture the bowls, containers for mate. Tropical habit plant, easily adapts to any climate, with annual production cycle sets itself as renewable source alternative. As an organic natural material, it is susceptible to degradation without treatment. Seeking to enable its use in the manufacture of containers for food and beverages it has prioritized the characterization of the structure and the application of waterproofing techniques. Seeking allow its use in the manufacture of containers for food and beverages prioritized the characterization of the structure and the application of waterproofing techniques. To prepare the samples were used fruits collected in Santa Maria, RS, and for waterproofing was used polyurethane resin on castor oil base. The characterization of the material which constitutes porongo was made thorugh electron microscope scanning, transmitted light microscope, thermal analysis, determination of moisture content, basic and apparent density and by three-dimensional scanning to analyze the dimensional variation. The characterization of resin was made by infrared spectroscopy with Fourier transform and the efficiency of the waterproofing was analyzed by water absorption and drop contact angle test. Microscopy enabled to identify the exocarp as a thin layer of compact cells, thus waterproof, and the mesocarp formed by parenchyma with cells that progressively increase in size towards the center, characterized by large empty spaces with thickened and lignified wall and intercellular communication channels, which makes the material be highly hydrophilic. By absorbing the water, there is filling in the vacuoles of the cells until the saturation without large re-arranging of the material dimensions, dimensionally stable. The gourd has very poor heterogeneous density, on average 0.124 g / cm³, in the density range of polymeric foams. Regarding to water-absorbing, untreated samples had mass increase of about 150% until saturation. After sealing, the samples with a resin layer had increased mass between 23% and 37%, while those with two resin layers only had increased mass from 5% to 6%, which indicates the sealing method efficiency.

It is well-known that concrete permeability is a good indicator of its expected durability until it remains uncracked. However, in various stages of its service life, different types of cracking in concrete can be developed due to exposure to different deterioration processes such as early plastic shrinkage or chloride-induced reinforcement corrosion. Although these cracks may not endanger concrete’s structural performance from the mechanical point of view, they create a pathway for aggressive ions that can initiate degradation processes, lead to increase in concrete permeability and thus reduce its durability. Cracking in concrete might not be preventable, but its capability to naturally seal small cracks, named autogenous self-healing (SH), provides an additional feature to manufacture more durable concrete structures. However, natural self-healing capability of concrete is limited and therefore it is typically omitted in the design of concrete structures. Hence, more attention has been recently paid to Engineered Self-healing Concrete (EShC) which is associated with artificially triggered healing mechanisms into the cementitious matrix by incorporating various substances such as crystalline products. EShC helps in reducing concrete permeability; thus, increasing its service-life and durability. Due to formation of needle-shaped pore-blocking crystals, Crystalline Admixtures (CA), as a candidate from the Permeability-Reducing Admixtures (PRA) category, can be implemented into concrete mixtures to fabricate EShC concretes. Crystalline waterproofing technology is not new, but still is unknown to many researchers, engineers, and construction industry professionals. The lack of knowledge of its microstructure and self-healing properties limits CA’s proper usage in the construction industry. The techniques to assess the self-healing capability of mortar and concrete are not well-standardized yet. No research work has been done to address certain durability characteristics of this material (i.e. electrical resistivity (ER) or chloride diffusivity) especially when combined with Supplementary Cementitious Materials (SCM) and Portland Limestone Cement (PLC). Since the resistance of concrete against ions’ penetration is a function of its permeability, it might be a straightforward and reliable parameter to rapidly evaluate concrete’s durability during its intended service life. Hence, electrical resistivity measurement is considered as an indirect and alternative tool for other time-consuming permeability testing techniques to examine the CA’s efficiency as it modifies the concrete’s microstructure by crystals’ deposition; thus, leads to permeability improvement. In comparison to previous studies, on a larger scale, this thesis aims to systematically study the effects of CA on the microstructural features, self-healing properties and long-term durability and resistivity of cement-based materials and in addition, draw some comprehensive conclusions on the use of CA in new and repair applications. This study is divided into three major phases to propose all-inclusive work on using CA in construction industry. To satisfy the goals of each individual phase, a test matrix consisting of a series of four mixes with variables such as use of PLC or presence of CA in powder form is considered. In order to address to the lack of research and industry knowledge discussed above, this PhD thesis includes the following phases: Phase (I) In this phase, the main focus is on the microstructural properties and the changes in the pore structure and chemical compositions of the cement phase of mortar mixes when treated with CA. These microstructural features are studied using Scanning Electron Microscope (SEM) and Scanning Transmission Electron Holography Microscope (STEHM). Moreover, physical and chemical characteristics of the hydration products are determined using image analysis and Energy Dispersive X-ray (EDX) Spectroscopy, respectively. Phase (II) This phase is allocated to macro-level investigation of durability characteristics such as chloride/water permeability and electrical resistivity of concrete structures containing CA and PLC cement. To non-destructively measure the chloride ion concentration in the field conditions, both changes in corrosion potential of rebars and concrete electrical resistivity in treated circular hollow-section steel reinforced columns exposed to simulated marine environment is monitored and compared over a 2-year period with control samples. In addition, laboratory-size concrete samples are studied to investigate the effects of CA presence on long-term resistivity, rapid chloride permeability, water permeability and chloride diffusivity of concrete. Later, a resistivity-based model is developed to predict long-term performance of concretes incorporating slag or metakaolin, studied in various environmental conditions. The long-term goal of this phase is to develop a standard design guideline and durability-based model. Phase (III) Using an innovative self-healing testing method [1], quantitative analysis of crack closure ability and self-healing potential of CA treated and control concretes with OPC or PLC cement is accomplished during this phase. The obtained results from first phase showed that hydrated CA particle revealed fine, compact, homogenous morphology examined by STEHM and its diffraction pattern after water-activation indicated nearly amorphous structure, however, diffuse rings, an evidence for short-range structural order and sub-crystalline region, were observed which requires further investigation. The SEM micrographs taken from specimen’s fractured surface showed formation of pore-blocking crystals for all treated mixes while similar spots in un-treated sections were left uncovered. Although needle-shaped crystals were observed in the treated mortar specimens, but not all of them had shapes and chemical compositions other than ettringite (well-known to form needle-like crystals). Using backscatter SEM images and EDX spectrums, examination of polished mortar sections with and without CA also showed typical hydration phases, forming in the control system. Results from phase II showed that concretes treated with CA had almost 50% lower water penetration depth and thus smaller permeability coefficient when compared with the virgin OPC or PLC concretes. According to salt ponding test results, the use of CA helped in enhancing the resistance to chloride penetration compared to control concrete. This improvement increases with increasing in concrete age. Strong linear relationship between Surface Resistivity (SR) and Bulk Resistivity (BR) data was observed which indicates that these test methods can be used interchangeably. The presence of SCM in concrete indicated considerable increase in both SR and BR compared to control concrete. Concretes incorporating slag or metakaolin have tendency to react more slowly (or rapidly in MK case), consume calcium hydroxide over time, form more Calcium Silicate Hydrate (C-S-H) gel, densify internal matrix, and also reduce OH- in the pores’ solution; thus, increase concrete electrical resistivity. For laboratory specimens, environmental conditions such as temperature variation and degree of water saturation indicated considerable effects on electrical resistivity measurements. As temperature or water content of concrete decreases, its electrical resistivity greatly increases by more than 2-3 times from reference environmental condition. This is mostly because of variation or accessibility in electron mobility. Experimental results from field investigation showed that electrical resistivity readings were highly influenced by the presence of rebar and concrete moisture conditions. In addition, concrete cover thickness and CA addition into cementitious matrix had a negligible effect on its resistivity. In the last phase, an optical microscope was used to measure the average crack width. OPC samples had an average measured crack width of 0.244 mm as compared to 0.245 mm for OPC-CA, 0.251 mm for PLC, and 0.247 mm for PLC-CA. Self-healing test results also showed 90% self-healing ratio for CA modified mix within few days after starting experiment. Addition of CA into the mix led to higher rates of healing and full crack closure (width up to 250 µm) when compared to reference concrete. An empirical equation that relates water initial flow rate to the crack width (Q∝〖CW〗^3) was also proposed in this phase. Presence of PLC and CA in the mixture resulted in positive improvement in crack-closing capability and self-healing ratio. / Graduate / 2019-09-11

A presente dissertação tem como objetivo discutir a importância da preservação ambiental em áreas urbanas. Nesse sentido, procedeu-se o estudo da impermeabilização de lotes urbanos inseridos em biótopos(unidades de paisagem) encontrados na bacia hidrográfica do córrego Águas Espraiadas, que se apresenta totalmente urbanizada. Realizou-se uma ampla caracterização ambiental e histórica da área estudada por meio da análise de lotes amostrais. Utilizou-se nesse trabalho o fator BAF (Fator de Biótopo de Área), cálculo utilizado no planejamento de áreas urbanizadas na cidade de Berlim (Alemanha). Este trabalho pretende oferecer subsídios para ações que levem à preservação de ambientes urbanos e uma melhor qualidade de vida urbana. / This work shows the importance of environmental preservation in urban areas. In this way, was developed the study of waterproofing of lots inserted in biotopes (units of landscape) found in the hydrographic basin of the Stream of Águas Espraiadas, which today is totally urbanized. A historical and ambiental characterization of the studied area was developed, through the analysis of variables of several lots. We use in this work a factor called BAF (Biotope Area Factor), calculation very used in the planning of Berlin city. This work intends to offer subsidies for the promotion of environmental preservation and for the best quality of urban life.