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Submitted by Flavio Hiochio Sato null (sato@dec.feis.unesp.br) on 2018-02-05T12:49:07Z No. of bitstreams: 1 FLAVIO SATO TESE ELETRICA_Final.pdf: 4905931 bytes, checksum: 7de4992b81a9e515eaf26a3c238221b5 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-02-05T18:40:28Z (GMT) No. of bitstreams: 1 sato_fh_dr_ilha.pdf: 4905931 bytes, checksum: 7de4992b81a9e515eaf26a3c238221b5 (MD5) / Made available in DSpace on 2018-02-05T18:40:28Z (GMT). No. of bitstreams: 1 sato_fh_dr_ilha.pdf: 4905931 bytes, checksum: 7de4992b81a9e515eaf26a3c238221b5 (MD5) Previous issue date: 2017-12-08 / O desenvolvimento de sistemas capazes de monitorar e controlar informações estão sendo cada vez mais utilizados, permitindo maior refinamento e confiança nos resultados. Na área instrumental de laboratório, existem situações que exigem maior controle sobre o ensaio. Com o atual avanço na área de microprocessadores, microcontroladores, sensores inteligentes, entre outros, têm impulsionado a utilização dos mesmos na melhoria e confiabilidade de processos mecânicos, químicos, físicos, biológicos, de inteligência artificial, de melhoria de qualidade de vida de pessoas com deficiência. Os processos podem ser melhorados utilizando equipamentos que possuem sistemas embarcados capazes de processar informações e fazer o controle a partir de sistemas operacionais que antes só eram possíveis nos computadores. Na área das grandes estruturas de concreto não é diferente, deve-se monitorar algumas variáveis que resultam em uma manifestação patológica conhecida como reação álcali-agregado, que é um fenômeno de expansão que afeta a durabilidade e a resistência mecânica do concreto, este fenômeno está ligado à algumas variáveis, a umidade relativa interna é umas delas. Existem várias pesquisas no sentido de inibir as reações álcali-agregados, e é sabido que um importante passo antes do acontecimento da reação álcali-agregado em obras hidráulicas, como as usinas hidroelétricas é o monitoramento da umidade e da temperatura no interior do concreto e, acompanhamento das fissuras inerentes do processo de expansão. O presente trabalho implementou um sistema de monitoramento de baixo custo, de temperatura e umidade para estruturas de concreto de barragens hidroelétricas, demonstrando a desnecessidade de monitoramento da umidade relativa por esta já estar a 100% no interior do concreto, paralelamente, desenvolveu-se um sistema de automação em usinas hidroelétricas para o controle dos deslocamentos desta reação, foi feito o levantamento das técnicas de correlação de imagens digitais (CID) e contatou-se que é promissor desde que o processamento dos programas de refinamento das imagens acompanhe a tecnologia de câmeras com alta resolução. / The development of systems able to monitor and control information is increasingly being used, allowing greater refinement and confidence in results. In the instrumental area of the laboratory, there are situations that require greater control over the test. With the current progress in the area of microprocessors, microcontrollers, intelligent sensors, among others, have encouraged the use of these in the improvement and reliability of mechanical, chemical, physical, biological, artificial intelligence, improving the quality of life of people with deficiency. Processes can be improved by using equipment that has embedded systems that can process information and control from operating systems that were previously only possible on computers. In the area of large concrete structures is not different, it is necessary to monitor some variables that result in a pathological manifestation known as alkali-aggregate reaction, which is an expansion phenomenon that affects the durability and the mechanical resistance of the concrete, this phenomenon is connected to some variables, the relative humidity is one of them. There are several researches to inhibit alkali-aggregate reactions and is known that an important step before the occurrence of the alkali-aggregate reaction in hydraulic works such as hydroelectric plants is the monitoring of humidity and temperature inside the concrete and, the inherent fissures of the expansion process. The present work implemented a low cost, temperature and humidity monitoring system for concrete structures of hydroelectric dams, demonstrating the lack of relative humidity monitoring because it is already 100% inside the concrete, in parallel, a system of automation in hydroelectric power plants to control the displacements of this reaction, a survey of digital image correlation techniques (DIC) was made and it has been contacted since the processing of image refinement programs accompanies the technology of cameras with high resolution.

Resumo: Várias pesquisas realizadas com compostos a base de lítio tem mostrado resultados satisfatórios na redução da expansão associada à reação álcali-sílica (RAS), mas ainda existem muitas dúvidas sobre seus mecanismos de ação. A presente pesquisa avaliou os efeitos de uma adição química a base de nitrato de lítio (LiNO3) na redução da expansão associada a RAS, utilizando várias dosagens. Os estudo dos efeitos do LiNO3 na RAS foi feito pelo método acelerado das barras de argamassa (ASTM C-1260) utilizando dois tipos de agregado reativo. Também foram realizados ensaios de expansão com uma adição mineral a base de cinza volante a fim de correlacionar os efeitos de uma adição mineral com uma química na redução da expansão devido a RAS. Ensaios de resistência à compressão e trabalhabilidade foram realizados também buscando algum efeito do LiNO3 nestas propriedades. Os resultados do ensaio ASTM C-1260 indicaram que as adições de lítio foram efetivas na redução da expansão para os dois tipos de agregados reativos, sendo que para as condições e materiais utilizados na presente pesquisa foi necessário uma de adição de LiNO3 com relação molar (Li2O/Na2Oeq) de 7,00 para reduzir a expansão ao valor aceitável pela norma de 0,10% aos 16 dias. Foi observado também intensidades de redução da expansão diferentes entre os dois tipos de agregados estudados devido a diferença de reatividade dos mesmos. Verificou-se um limite de adição de lítio para o basalto, onde não havia mais redução significativa de expansão com o aumento da dosagem de adição. Observou-se também que as misturas contendo LiNO3 reduziram a expansão ao longo dos 30 dias, enquanto nas misturas contendo FA a expansão continuou a aumentar ao longo do teste. Os ensaios de condição de trabalhabilidade e de resistência à compressão mostraram que o LiNO3 não afeta consideravelmente estas propriedades. / Abstract: Lithium compounds have been shown satisfactory results for the reduction of the expansion due to alkali-silica reaction (ASR), but there are many doubts about its mechanisms of action. The present research evaluated the effects of a chemical addition to lithium nitrate based (LiNO3) on the reduction of expansion associated with ASR, utilizing several dosages. For the study of the effects of the LiNO3 on the ASR it was used the accelerated mortar bar method (ASTM C-1260), with two kinds of reactivate aggregate. Mortar bars were molded also with a mineral addition of fly ash based (FA) with the objective to compare the effects of a mineral addition with a chemistry on the expansion due ASR. Compressive strength and consistence index tests had been carried also for searching some effects of the LiNO3 at these properties. The results from ASTM C-1260 showed that the addition of LiNO3 were effective on the expansion reduction for two kinds of reactive aggregate, which current conditions and materials on this research required a LiNO3 addition with (Li/Naeq) of 7,00 molar ratio to decrease the expansion to an acceptable value of 0,10% on 16 days. Also, the intensity of the expansion reduction was observed between two kinds of studied aggregates by their reactivity difference. A lithium additive upper bound was verified for the basalt, where it did not have more significant reduction of expansion with the increase of the dosage of addition. Also, was observed that admixtures that contained LiNO3 have reduced the expansion trough 30 days, while on the admixtures that contained FA the expansion grew up. The results obtained for the compressive strength and consistence index tests showed no significant differences between mixtures with and without LiNO3 admixture. / Orientador: Jorge Luís Akasaki / Coorientador: Haroldo de Mayo Bernardes / Banca: Marco Antonio Morais Alcantara / Banca: Vladimir Antonio Paulon / Mestre

A reação álcali-agregado é uma patologia do concreto conhecida há mais de 60 anos no meio técnico, e envolve os álcalis, provenientes em maior parte do cimento, e certos constituintes mineralógicos dos agregados. O produto desta reação é um gel higroscópico, que, em contato com a água, aumenta de volume consideravelmente. Os danos decorrentes da reação envolvem principalmente o desenvolvimento de um quadro de fissuração intenso, o que acarreta outras diversas manifestações patológicas, e movimentações de peças estruturais. Os relatos mais freqüentes de ocorrência da reação sempre foram em estruturas hidráulicas, tais como as barragens, em função do permanente contato com a água. Entretanto, nos últimos anos, diversos outros tipos de estruturas têm sido afetados, inclusive fundações de edificios, deixando o problema em evidência. O único modo de combater a reação é prevení-la através do uso de adições minerais, e para tal se faz necessário avaliar o agregado em questão, dispondo de um método de ensaio confiável. Este trabalho buscou analisar um dos métodos de ensaio mais utilizados no mundo todo para avaliar a reação álcali-agregado, a ASTM C 1260. Foram modificados alguns parâmetros de moldagem para verificar a influência destes nos resultados de expansão fornecidos pelo ensaio. Avaliaram-se os fatores: relação água/cimento, consistência da argamassa e forma do grão de agregado, e no total foram conduzidos 63 diferentes ensaios de expansão para analisar a influência destes fatores. Ensaios auxiliares foram realizados para justificar os resultados, e utilizou-se tratamento estatístico para verificação da validade dos mesmos. Foi observado que a forma de britagem do agregado, para posterior realização do ensaio, interfere diretamente nas condições de moldagem. E, o mais importante: isto resulta em expansões diferenciadas na idade de avaliação do agregado. Para evitar classificações errôneas de agregados através do uso da ASTM C 1260, uma norma usada em vários países, sugere-se que sejam fixados o maior número possível de parâmetros de moldagem. / The alkali-aggregate reaction 1s a concrete pathology known for more than 60 years, involving the alkalis (mostly from the cement), and some mineralogical components of the aggregates. The product o f this reaction is a hygroscopic gel that, in contact with water, has its volume greatly increased. The damage resulting from this reaction is mainly a situation of intense craking, which causes other pathological manifestations and movements of the structure. The most frequent reports o f this reaction have always been in hydraulic structures, such as dams, caused by the permanent contact with water. However, in the last few years, many other kinds of structures have been affected, including building foundations; which brought the problem to international evidence. The only way to prevent the expansion caused by the reaction is the use o f mineral admixtures as a substitute o f part o f the cement content, but first it is necessary to evaluate the aggregate in use, with a satisfactory test method. This work' s purpose is to analyze one o f the test methods commonly used throughout the world to evaluate the alkali-aggregate reaction, the ASTM C 1260. Some molding parameters have been modified so as to check their influence on the results of expansion obtained through this test. These factors have been evaluated: water/cement ratio, mortar consistency and shape of the aggregate particle. A total of 63 different tests of expansion were conducted to evaluate their influence. Additional tests were done so as to justify the results, and statistical analysis was used to validate the results. It was observe that the way the aggregate is crushed, for subsequent execution of the test, directly interferes in the conditions of molding. And, the most important: the way the aggregate is crushed results in different expansions and it is increased with the age of the evaluation of the test. To prevent a erroneous classification o f the aggregates through the use of ASTM C 1260, a standard used in many countries, it is suggested that test conditions should be better defined.

abstract: Alkali-activated aluminosilicates, commonly known as "geopolymers", are being increasingly studied as a potential replacement for Portland cement. These binders use an alkaline activator, typically alkali silicates, alkali hydroxides or a combination of both along with a silica-and-alumina rich material, such as fly ash or slag, to form a final product with properties comparable to or better than those of ordinary Portland cement. The kinetics of alkali activation is highly dependent on the chemical composition of the binder material and the activator concentration. The influence of binder composition (slag, fly ash or both), different levels of alkalinity, expressed using the ratios of Na2O-to-binders (n) and activator SiO2-to-Na2O ratios (Ms), on the early age behavior in sodium silicate solution (waterglass) activated fly ash-slag blended systems is discussed in this thesis. Optimal binder composition and the n values are selected based on the setting times. Higher activator alkalinity (n value) is required when the amount of slag in the fly ash-slag blended mixtures is reduced. Isothermal calorimetry is performed to evaluate the early age hydration process and to understand the reaction kinetics of the alkali activated systems. The differences in the calorimetric signatures between waterglass activated slag and fly ash-slag blends facilitate an understanding of the impact of the binder composition on the reaction rates. Kinetic modeling is used to quantify the differences in reaction kinetics using the Exponential as well as the Knudsen method. The influence of temperature on the reaction kinetics of activated slag and fly ash-slag blends based on the hydration parameters are discussed. Very high compressive strengths can be obtained both at early ages as well as later ages (more than 70 MPa) with waterglass activated slag mortars. Compressive strength decreases with the increase in the fly ash content. A qualitative evidence of leaching is presented through the electrical conductivity changes in the saturating solution. The impact of leaching and the strength loss is found to be generally higher for the mixtures made using a higher activator Ms and a higher n value. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) is used to obtain information about the reaction products. / Dissertation/Thesis / M.S. Civil Engineering 2012

abstract: The alkali activation of aluminosilicate materials as binder systems derived from industrial byproducts have been extensively studied due to the advantages they offer in terms enhanced material properties, while increasing sustainability by the reuse of industrial waste and byproducts and reducing the adverse impacts of OPC production. Fly ash and ground granulated blast furnace slag are commonly used for their content of soluble silica and aluminate species that can undergo dissolution, polymerization with the alkali, condensation on particle surfaces and solidification. The following topics are the focus of this thesis: (i) the use of microwave assisted thermal processing, in addition to heat-curing as a means of alkali activation and (ii) the relative effects of alkali cations (K or Na) in the activator (powder activators) on the mechanical properties and chemical structure of these systems. Unsuitable curing conditions instigate carbonation, which in turn lowers the pH of the system causing significant reductions in the rate of fly ash activation and mechanical strength development. This study explores the effects of sealing the samples during the curing process, which effectively traps the free water in the system, and allows for increased aluminosilicate activation. The use of microwave-curing in lieu of thermal-curing is also studied in order to reduce energy consumption and for its ability to provide fast volumetric heating. Potassium-based powder activators dry blended into the slag binder system is shown to be effective in obtaining very high compressive strengths under moist curing conditions (greater than 70 MPa), whereas sodium-based powder activation is much weaker (around 25 MPa). Compressive strength decreases when fly ash is introduced into the system. Isothermal calorimetry is used to evaluate the early hydration process, and to understand the reaction kinetics of the alkali powder activated systems. A qualitative evidence of the alkali-hydroxide concentration of the paste pore solution through the use of electrical conductivity measurements is also presented, with the results indicating the ion concentration of alkali is more prevalent in the pore solution of potassium-based systems. The use of advanced spectroscopic and thermal analysis techniques to distinguish the influence of studied parameters is also discussed. / Dissertation/Thesis / M.S. Engineering 2013

A montagem de um sistema que permite a detecção de modulação no coeficiente de absorção ótica, devido ao campo elétrico aplicado, foi concluída. A máxima sensibilidade atingida foi de &#916 K / K = 1,5 x 10-6 com resolução em comprimento de onda de 3 nm. O efeito Stark de 2&#170 ordem, na freqüência dupla da do campo elétrico aplicado foi medido para o centro F em KCl e KBr e comparado com provisões teóricas. Os valores obtidos para o KCl coincidem com os de Chiarotti, o que confirma o bom funcionamento do sistema, e diferem dos valores calculados teoricamente. Essa diferença é atribuída à correção do campo local. Os valores obtidos experimentalmente para a variação relativa do coeficiente de absorção foram: para KCl: &#916K / K = 2,93 x 10-5 (78&#176 K) para KBr: &#916K / K = 2,85 x 10-5 (78&#176 K) / The assembly of a system which allows the detection of modulation in the coefficient of optical absorption, due to the applied electrical field, was completed. The maximum sensitivity achieve was &#916 K / K = 1,5 x 10-6, in wave length, of 3 nm. The Stark effect of second order, in the frequency twice as that of the applied electrical field was measured for the center F in KCl and KBr and compared with theoretical previsions. The values obtained for KCl coincide with those of Chiarotti\'s, which confirms the good functioning of the system, and differ from the values calculated theoretically. This difference in ascribed to the correction of the local field. for KCl: &#916K / K = 2,93 x 10-5 (78&#176 K) for KBr: &#916K / K = 2,85 x 10-5 (78&#176 K).

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