Este trabalho caracterizou os siltitos do Grupo Itararé, rocha branda proveniente da amostragem de pedreira localizada nas proximidades de futuro empreendimento brasileiro, o Trem de Alta Velocidade. Objetivou entender as causas da pronunciada e rápida alteração da rocha intacta, e simular, em condições controladas de laboratório, a degradação hidromecânica causada pela simples variação da umidade relativa do ar. Para tal, estabeleceu-se técnica de amostragem de testemunhos por meio da extração via seca com ar-comprimido, e processo de intemperismo artificial, composto por 4 ciclos de 2 etapas (secagem e umedecimento). O processo se deu em dessecadores, sendo a variação da umidade ocasionada pela técnica do vapor e sílica gel. O acompanhamento da degradação dos corpos de prova efetuou-se com duas técnicas não-destrutivas de propagação de ondas: o pulso ultrassônico e a excitação por impulso (sistema Sonelastic). Em paralelo, realizou-se a caracterização geotécnica dos siltitos em umidade natural, com ensaios mineralógicos, físicos, físico-mecânicos, físico-químicos e de alteração laboratorial. Por meio desta metodologia, foi possível estimar as minorações do módulo de deformabilidade e da resistência, além das causas físico-químicas da degradação. / This work characterized the siltstones of the Itararé Group, a soft rock sampled in a quarry located near a future Brazilian venture, the High Speed Train. It aims at understanding the causes of the pronounced and fast changes of the intact rock, and simulate in controlled laboratory conditions the hydro degradation process caused by simple variation of relative air humidity. Dry sampling technique with compressed air was used to extract samples from blocks, and the process of artificial weathering consisted on 4 cycles of 2 steps (drying and wetting). The process occurred in desiccators, where moisture variation was caused by the vapor technique and silica gel. The monitoring of the specimens degradation was performed with two non-destructive wave propagation techniques: the ultrasonic pulse and the impulse excitation (Sonelastic system). A geotechnical characterization of the siltstones in natural moisture condition was made in parallel, consisting on mineralogical, physical, physical-mechanical, physical-chemical and durability tests. By this methodology, it was possible to estimate the mitigation of the deformability modulus and strength besides the physical- chemical causes of degradation.

A resistência à compressão uniaxial e o módulo de deformabilidade são parâmetros que descrevem o comportamento de materiais rochosos frente a solicitações por esforços. É prática corriqueira em investigações geológico-geotécnicas para projetos de engenharia estimar a resistência de maneira preliminar com base em propriedades de tenacidade, dureza e friabilidade, aferindo à rocha graus de coerência. Dados laboratoriais referentes a aspectos físicos, texturais e mineralógicos de arenitos da Formação Piramboia, Bacia do Paraná, amostrados via sondagens mistas na região de Anhembi e Santa Maria da Serra, Estado de São Paulo, foram correlacionados entre si e a parâmetros geomecânicos como resistência à compressão uniaxial, módulo de deformabilidade e graus de coerência. As fácies reconhecidas nos arenitos foram agrupadas em associações de dunas e interdunas e suas rochas classificadas como quartzo arenitos e arenitos feldspáticos ou subarcóseos, com cimentação principalmente de esmectita ou material argilo- ferruginoso. Encontraram-se correlações significativas da resistência à compressão uniaxial com tamanho médio dos grãos e densidade, inversa no primeiro caso e direta no segundo. Já o módulo de deformabilidade apresentou correlação significativa inversa com proporção de pelíticos, e direta com tamanho médio dos grãos, desvio padrão da distribuição granulométrica e grau de empacotamento. Arenitos característicos de inundações efêmeras em domínio de interdunas úmidas, com maiores teores de pelíticos, apresentaram módulos de deformabilidade baixos e resistências altas em comparação aos arenitos de demais fácies. Variações da composição mineralógica do arcabouço não se mostraram suficientes para influenciar significativamente o comportamento geomecânico dos arenitos. / The uniaxial compressive strength and the deformability modulus are parameters that describe the behavior of rock materials under stress. It is an everyday practice in geological and geotechnical investigations for engineering projects to estimate strength in a preliminary fashion, based on properties such as tenacity, toughness and friability, attributing to the rock a qualitative term describing its strength. Laboratorial data on physical, textural and mineralogical aspects of sandstones of the Piramboia Formation, Paraná Basin, obtained by core drillings in the region of Anhembi and Santa Maria da Serra, state of São Paulo, were correlated to each other and to geomechanical parameters such as uniaxial compressive strength, deformability modulus and qualitative terms describing their strength. The recognized sandstone facies were grouped in dune and interdune associations and their rocks were classified as quartz arenites and feldspathic arenites or subarkoses, whose cementation is mainly composed of smectite or ferruginous clay material. Significant correlations of uniaxial compressive strength with mean grain size and density were found, inverse in the first case and direct in the second. On the other hand, the deformability modulus showed a significant inverse correlation with the amount of pelitic material, and direct with mean grain size, standard deviation of grain size distribution and packing density. Sandstones characteristic of ephemeral floods in the domain of wet interdunes, with greater amounts of pelitic material, presented low values of deformability modulus and high strength values compared to the other facies. Variations in the mineral composition of the framework were not sufficient to significantly influence the geomechanical behavior of the sandstones.

[pt] Projetos estruturais que empregam concretos com resistências mais elevadas, ou seja, maiores que 40 MPa, nomeados Concretos de Alto Desempenho, são cada vez mais freqüentemente utilizados. Sabe-se, entretanto, que as propriedades destes concretos são diferenciadas daquelas dos concretos considerados convencionais, necessitando-se estudos que visem, principalmente, mensurar a realidade dentro dos materiais disponíveis em nosso país. Este trabalho experimental estuda as principais propriedades deste material: resistência à compressão, resistência à tração por compressão diametral, Módulo de Elasticidade e permeabilidade, através da determinação do índice de vazios. Após um estudo sobre métodos de dosagem mais utilizados e empregando-se materiais disponíveis no Rio de Janeiro, foram moldados um total de 230 corpos de prova para resistências características à compressão de 40MPa, 60 MPa, 80 MPa e 100 MPa. Foi realizado um estudo sobre compatibilidade entre superplastificante e aglomerante. Com os dados obtidos experimentalmente, foram relacionados resistências à tração por compressão diametral, módulo de elasticidade e porosidade com resistência à compressão axial. Estes resultados foram comparados com as recomendações das principais normas internacionais e com as propostas de alguns pesquisadores que foram encontradas na literatura. / [en] High Performance Concrete, i.e., those whose compressive strength is higher than 40 Mpa, have been used in a wide range of Civil Engineering applications. Notwithstanding that, it is known that their mechanical and physical properties are different from those of their conventional counterparts. In this dissertation, it is studied mixture proportion methods with good acceptance rate, preparing 230 specimens with materials available in Brazil s state of Rio de Janeiro and that have compressive strength of 40 MPa, 60MPa, 80 MPa and 100 MPa. For each prepared specimen, it is studied its mechanical properties, compressive strength, splitting tensile strength, modulus of elasticity and porosity for the determination of the emptiness ratio. It is also studied the compatibility between superplasticizer and cement materials. It is also performed a comparison between the experimental data and the expressions available in the literature, as well as the relation between the compressive strength, splitting tensile strength, modulus of elasticity and the porosity.

Materiais odontológicos inovadores que apresentem propriedades antimicrobianas são altamente desejáveis na cavidade oral. O objetivo deste estudo foi avaliar a atividade antimicrobiana do vanadato de prata nanoestruturado (&beta;-AgVO3) incorporado em duas resinas acrílicas frente a Candida albicans, Streptococcus mutans, Staphylococcus aureus e Pseudomonas aeruginosa, além de examinar as propriedades mecânicas e o padrão de incorporação do nanomaterial nas resinas. O nanomaterial foi caracterizado por difração de raios X (DRX), espectroscopia no infravermelho por transformada de Fourier (FTIV), análise elementar por energia dispersiva (EDS) e microscopia eletrônica de varredura (MEV). As propriedades antimicrobianas das resinas acrílicas incorporadas com diferentes porcentagens de &beta;-AgVO3 foram investigadas pelo método de redução do XTT, unidades formadoras de colônias (UFC) e microscopia confocal à laser e o comportamento mecânico por meio de ensaios de dureza e rugosidade superficial, resistência à flexão, à compressão e ao impacto. O padrão de incorporação do &beta;-AgVO3 nas resinas foi analisado por microscopia eletrônica de varredura (MEV) e análise elementar por energia dispersiva (EDS). Os dados foram analisados por ANOVA, Tukey e pelo teste Generalized Linear Models (&alpha;=0,05). Para ambas as resinas, em relação ao grupo controle, a incorporação de 5% e 10% de &beta;-AgVO3 reduziram significantemente a atividade metabólica de C. albicans e P. aeruginosa (p<0,05), enquanto que para S. mutans houve redução significante apenas com a incorporação de 10% (p<0,05). Não houve diferença na atividade metabólica pelo método do XTT frente a S. aureus (p> 0,05). Para ambas as resinas, observou-se uma redução significativa no número de UFC/mL de C. albicans para o grupo incorporado com 10% de &beta;-AgVO3 e de S. mutans para os grupos com 2,5%, 5% e 10% do nanomaterial (p<0,05). Para S. aureus e P. aeruginosa, houve redução significante com a incorporação de 5% e 10% (p<0,05). A dureza superficial da resina termopolimerizável permaneceu inalterada pela incorporação do nanomaterial (p>0,05) e da autopolimerizável aumentou com 0,5% (p<0,05). Concentrações maiores que 1% promoveram redução na resistência flexural das resinas (p<0,05) enquanto que a rugosidade superficial permaneceu inalterada (p>0,05). A resistência à compressão da resina autopolimerizável permaneceu inalterada (p>0,05) e da termopolimerizável reduziu com a incorporação de 0,5% e 10% (p<0,05). As concentrações de 5% e 10% promoveram redução significante na resistência ao impacto das resinas, em relação ao controle (p<0,05). A caracterização das resinas quanto a dispersão da carga utilizada mostrou a presença de domínios de &beta;-AgVO3 ao longo da matriz polimérica seguindo um padrão circular. Conclui-se que o método proposto foi capaz de promover atividade antimicrobiana às resinas acrílicas frente aos micro-organismos avaliados, sendo a mesma dependente da concentração do nanomaterial. Porém, alterações na dispersão do &beta;-AgVO3 na matriz dos polímeros são necessárias para não sacrificar as propriedades mecânicas e para potencializar o efeito antimicrobiano / Innovative dental materials that have antimicrobial properties are highly desirable in the oral cavity. The aim of this study was to evaluate the antimicrobial activity of nanostructured silver vanadate (&beta;-AgVO3) incorporated into two acrylic resins against Candida albicans, Streptococcus mutans, Staphylococcus aureus and Pseudomonas aeruginosa, while examining the mechanical properties and the pattern of nanomaterial incorporation into resins. The nanomaterial was characterized by X-ray diffraction (XRD), infrared spectroscopy Fourier transform (FTIR), elemental analysis by energy dispersive (EDS) and scanning electron microscopy (SEM). The antimicrobial properties of acrylic resins incorporated with different percentages of &beta;-AgVO3 were investigated by the reduction of XTT method, colony forming units (CFU) and confocal laser microscopy and the mechanical behavior through hardness, surface roughness, flexural, compression and impact tests. The pattern of incorporation of &beta;-AgVO3 resins was analyzed by scanning electron microscopy (SEM) and elemental analysis by energy dispersive (EDS). Data were analyzed by ANOVA, Tukey test and the Generalized Linear Models (&alpha; = 0.05). For both resins, compared to the control group, the incorporation of 5% and 10% &beta;-AgVO3 caused a significantly reduced in the metabolic activity of C. albicans and P. aeruginosa (p <0.05), while for S. mutans significant reduction was observed only with the incorporation of 10% (p <0.05). There was no difference in metabolic activity by XTT method against S. aureus (p> 0.05). For both resins, there was a significant reduction in the number of CFU / mL for C. albicans incorporated group with 10% &beta;-AgVO3 and S. mutans in groups with 2.5%, 5% and 10% of nanomaterial (p <0.05). For P. aeruginosa and S. aureus, there was a significant decrease with the incorporation of 5% to 10% (p <0.05). The surface hardness of the heat-cured resin was unchanged by the incorporation of the nanomaterial (p <0.05) and increased self-cured with 0.5% (p <0.05). Concentrations above 1% promote the reduction in flexural strength of the resins (p <0.05) while the surface roughness remained unchanged (P> 0.05). The compressive strength of the self-cured resin remained unchanged (P> 0.05) and heat-cured reduced with the incorporation of 0.5% and 10% (p <0.05). Concentrations of 5% and 10% caused a significant reduction in impact strength of resins, compared to control (p <0.05). The characterization of the resins as the dispersion of the filler used showed the presence of &beta;-AgVO3 domains along the polymer matrix following a circular pattern. It was concluded that the proposed method was able to promote antimicrobial activity to acrylic resins against microorganisms evaluated, with the same concentration dependent of the nanomaterial. However, changes in the &beta;-AgVO3 dispersion in the polymer matrix are necessary to do not sacrifice the mechanical properties and to enhance the antimicrobial effect

Cette étude vise à contribuer au développement d’un produit de construction à faible impact environnemental utilisant la terre crue. Pour cela, le comportement hygro-mécanique de la terre crue compressée à haute pression par une technique novatrice mise au point dans ce projet a été caractérisé. De plus, plusieurs méthodes de stabilisation ont été évaluées afin d’améliorer la durabilité de ce matériau, notamment vis-à-vis de l’érosion induite par l’eau. Une vaste campagne d’essais expérimentaux a été menée sur ces matériaux stabilisés ou non, à deux échelles différentes : les caractérisations des échantillons cylindriques (petite échelle) ont tout d’abord permis de sélectionner la formulation optimale. Par la suite, les tests menés à grande échelle sur les briques de terre compressée ont contribué à développer un produit pour la construction. Une nouvelle technique de fabrication basée sur l’application d’une contrainte de compactage très élevée (hyper-compactage) a été mise au point. Son objectif principal est d’augmenter la densité du matériau afin d’améliorer ses performances mécaniques. Les échantillons compactés par la méthode proposée présentent une densité sèche d’environ 2320 kg/m3, ce qui représente la valeur la plus élevée jamais enregistrée dans la littérature pour une terre non stabilisée. Les effets de la contrainte de compactage sur la microstructure du matériau ont été analysés par intrusion au mercure et adsorption d’azote liquide. Les résultats montrent que l’augmentation de la contrainte de compactage réduit la porosité du matériau, majoritairement les grands pores inter-agrégats. Cependant, le compactage mécanique influence peu les petits pores intra-agrégats. L'approfondissement de la caractérisation des propriétés microstructurales des échantillons stabilisés constitue un développement intéressant de ce travail. La résistance et la rigidité des échantillons non stabilisés et stabilisés ont été mesurées. Ces essais mécaniques confirment que la méthode d'hyper-compactage permet d’améliorer grandement la réponse mécanique du matériau par rapport aux techniques de fabrication existantes. Ainsi, les briques réalisées présentent une résistance en compression comparable à celle-là des matériaux traditionnels de construction (e.g. terre stabilisée et briques en terre cuite). Pour compléter cette étude, des essais mécaniques à l’échelle paroi sont à mener. Le comportement hygroscopique des échantillons stabilisés et non stabilisés a été analysé par la mesure du paramètre MBV (i.e. Moisture Buffering Value), qui traduit la capacité d’échange avec la vapeur d’eau. Il s'avère que la terre non stabilisée possède une excellente capacité à absorber et relarguer l’humidité ambiante. Cette capacité est, par contre, réduite pour les échantillons stabilisés testés dans le cadre de cette étude. La caractérisation du comportement thermique de la terre compressée à haute pression ainsi que l’analyse expérimentale des transferts thermo-hygroscopiques à l’échelle paroi représentent deux compléments d'étude afin de préciser le comportement hygroscopique d'un mur à base de terre crue. Enfin, la durabilité par rapport à l’érosion induite par l’eau des briques stabilisées et non stabilisées a été estimée à travers les essais d’immersion, de succion et de contact qui sont prévus par la norme DIN 18945 (2013). Les briques stabilisées montrent une meilleure résistance à l’eau par rapport aux briques non stabilisées. Toutefois, des études supplémentaires sont nécessaires pour améliorer les méthodes de stabilisation garantissant la durabilité dans le cas d'applications structurelles exposées aux intempéries, tout en maintenant de bonnes performances hygro-mécaniques et un faible impact environnemental. / The present work explores the hygro-mechanical behaviour of a raw earth material and investigates different stabilisation techniques to improve the durability of the material against water erosion. An extensive campaign of laboratory tests was performed on both unstabilised and stabilised materials at two different scales: small cylindrical samples and large bricks. An innovative manufacturing method based on the application of very high compaction pressures (hypercompaction) was proposed. Also, the compaction load was maintained constant for a sufficient period of time to allow soil consolidation. The main objective was to increase material density, thus improving mechanical performance. Samples compacted with the proposed method exhibited a dry density of about 2320 kg/m3, which is the highest value registered in the literature for an unstabilised earthen material. The effect of the compaction pressure on the material fabric was assessed by means of mercury intrusion porosimetry and nitrogen adsorption tests. Results showed that the increase of compaction pressure reduced material porosity with major effects on large inter-aggregate pores. On the contrary, small intra-aggregate pores were not affected by the mechanical compaction. Mechanical tests were then performed to measure stiffness and strength of both unstabilised and stabilised samples. These tests demonstrated that hypercompaction can largely improve the mechanical response of the material over conventional manufacturing methods. Hypercompacted bricks showed a compressive strength comparable with that of traditional building materials, such as stabilised compressed earth and fired bricks. The hygroscopic behaviour of both unstabilised and stabilised samples was investigated. The capacity of the samples to absorb/release water vapour was assessed by measuring their moisture buffering value (MBV). Results showed that unstabilised earth has an excellent capacity to buffer ambient humidity. This capacity was significantly reduced by the different stabilisation techniques tested in the present work. Finally, the durability against water erosion of both unstabilised and stabilised bricks was assessed by performing different tests prescribed by the norm DIN 18945 (2013). Stabilised bricks exhibited a higher resistance against water erosion compared to unstabilised bricks. Still, these materials cannot be adopted for structural applications exposed to natural weathering as indicated by the norm DIN 18945 (2013). Therefore, further investigation is required to identify novel stabilisation methods that can balance the needs of sustainability, durability, moisture buffering and mechanical performance.

The aim of this study was to assess the strength, durability properties and corrosion resistance of concrete samples using supplementary cementitious blended materials. In this investigation, three supplementary concrete materials (SCMs) were used together with ordinary Portland Cement (OPC) to form cementitious blends at different proportions. The supplementary materials are silica fume (SF), ground granulated blast furnace slag (GGBS) and fly ash (FA). Sixteen (16) different proportions of the cementitious blends were produced. Tests carried out on concrete samples include slump test, compressive strength, oxygen permeability, sorptivity, porosity, chloride conductivity test, resistance to chloride and sulphate attack. The electrode potentials of tested samples were also observed using electrochemical measurements. Concrete specimens prepared with 10%, 20%, 30%, 40%, up to 60% of blended cements replacement levels were evaluated for their compressive strength at, 7, 14, 28, 90 and 120 days while the specimens were evaluated for durability tests at 28, and 90 days respectively. The results were compared with ordinary Portland cement concrete without blended cement. Voltage, and temperature measurements were also carried out to understand the quality of concrete. The corrosion performance of steel in reinforced concrete was studied and evaluated by electrochemical half-cell potential technique in both sodium chloride, and magnesium sulphate solutions respectively. The reinforced concrete specimens with centrally embedded 12mm steel bar were exposed to chloride and sulphate solutions with the 0.5 M NaCl and MgSO4 concentrations respectively. An impressed voltage technique was carried out to evaluate the corrosion resistance of the combination of quaternary cementitious blended cement, so as to get the combination with optimum performance. Improvement of strength, durability, and corrosion resistance properties of blended concrete samples are observed at different optimum percentages for binary, ternary and quaternary samples. The effect of cementitious blends is recognized in limiting the corrosion potential of the tested SCM concrete samples. Generally, the cementitious blends with limited quantity of SF to 10% have the potential to produce satisfactory concrete. These should however be used for low cost construction, where high quality concrete is not required. / Civil and Chemical Engineering / M. Tech. (Chemical Engineering)

<p>U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja mogućnosti primjene biopepela, nastalog sagorjevanjem žetvenih ostataka, kao mineralnog dodatka u cementnim kompozitima: malterima i betonima. Istraživanje je zasnovano na komparativnoj analizi 27 vrsta maltera u kojima je varirana vrsta biopepela i vrsta sitnozrnog agregata i 12 vrsta betona koje se razlikuju u vrsti veziva i u krupnom agregatu. Na očvrslom malteru su ispitani: konzistencija, čvrstoća pri pritisku i kapilarno upijanje vode, a na očvrslom betonu ispitivani su kapilarno upijanje vode, skupljanje pri sušenju, čvrstoća pri pritisku, dinamički modul elastičnosti, otpornost na habanje, vodonepropustljivost i čvrstoća na savijanje. Istaknuto je da se primjenom biopepela kao zamjene dijela cementa mogu dobiti konstrukcijski malteri i betoni, odnosno betoni sa zadovoljavajućim fizičkim i mehaničkim karakteristikama.</p> / <p>The dissertation presents the results of an own experimental research on the possibility of using biomass ash as a mineral additive in cement composites: mortar and concrete. The research is based on a comparative analysis of 27 types of mortars in which the type of biomass ash and the type of fine-grained aggregate were varied, as well as 12 types of concrete that differ in the type of binder and coarse aggregate. Following properties were tested on hardened mortars: consistency, compressive strength and capillary water absorption, and on hardened concrete: capillary water absorption, drying shrinkage, compressive strength, dinamic modulus of elasticity, wear resistance, waterpermeability and flexural strength. It was pointed out that biomass ash can be used as a replacement of a part of cement, thereby obtaining satisfactory physical and mechanical characteristics.</p>

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / Land is subsiding over a heavily mined aquifer in south central Arizona. Subsidence damages are inventoried to help provide a basis upon which cost studies can be performed to determine actions to lessen the economic impact of these damages. Water table drawdown produces increasing loading stress by three ways: changes in bouyant support of aquifer grains, changes in water table, or both. Two types of subsidence are recognized--one-directional compression, and near surface phenomenon. Damages due to natural structures, and to man-made structures are reviewed. Agricultural damages include field releveling, ditch repair and well damage. Damages to transportational facilities include highways, bridges, pipelines, and railroads. Damages to domestic and urban structures are suggested. Questionnaires, interviews and on-site inspections were used to collect information on land subsidence damages in the study area.

In the face of technological advances in concrete science emerged so-called special concretes and, among these, the self-compacting concrete (SCC), developed in Japan in the 1980s. This concrete is currently considered one of the greatest advances in concrete technology in view of its numerous advantages (decrease of construction duration, decrease of concreting labor, improvement of the working environment, improvement of the quality and durability of structures etc.). The production of SCC requires different mix design methods related to those applied for conventional concrete. Among these differences are highlighted the determination of the aggregate compositions and the addition of fine materials and chemical admixtures. In the case of determining the aggregate composition, the method of unit mass has been applied in SCC. However, it is common the use of this method in binary combinations, but for ternary and quaternary combinations it is quite limited. Thus, this work aimed to analyze the influence of different combinations and compositions of aggregates, determined by the method of unit mass and void ratio, to obtaining and characterization of SCC. For this, initially the procedures of the method was standardized. It was used two types of natural fine and coarse aggregates with different physical characteristics. It was produced 9 different aggregate compositions, four binary, ternary and quaternary four. For each composition, one SCC was formulated, based on previous dosage studies. The selfcompactability properties of the concrete were analyzed by spreading, V funnel test and L box test. In case hardened state the compressive strength was determined. The results showed that different methods of execution procedures showed no differences. The method of unit mass proved to be efficient in determining aggregate compositions to supply the SCC. For the same volume and paste composition (cement, water, chemical and mineral admixtures) the quaternary composition was the most efficient in meeting the properties of selfcompactability and compressive strength. / Diante dos avanços tecnológicos na ciência do concreto surgiram os chamados concretos especiais e, dentre estes, pode-se citar o concreto autoadensável (CAA), desenvolvido no Japão, na década de 1980. Este concreto é atualmente considerado um dos maiores avanços na tecnologia do concreto tendo em vista as suas inúmeras vantagens (diminuição do tempo da obra, diminuição da mão de obra de concretagem, melhora o ambiente de trabalho, melhora a qualidade e durabilidade da estrutura e etc.). A obtenção do CAA requer métodos de dosagens diferentes dos aplicados em concretos convencionais. Dentre essas diferenças se destacam a determinação das composições de agregados e a adição de materiais finos e aditivos químicos. Em se tratando da determinação da composição de agregados o método da massa unitária vem sendo aplicado em CAA. Entretanto é comum sua utilização em combinações binárias, já para combinações ternárias e quaternárias é bastante limitado. Neste sentido, foram analisadas diferentes combinações e composições de agregados, determinadas pelo método da massa unitária e do índice de vazios, na obtenção e caracterização de CAA. Para isso, inicialmente procurou-se padronizar os procedimentos de execução do método. Utilizou-se dois tipos de agregados miúdos e graúdos naturais com diferentes características físicas, sendo produzidas 9 composições distintas, sendo quatro binárias, quatro ternárias e uma quaternária. Para cada composição foi formulado um CAA, tomando como base a dosagem em estudos prévios. As propriedades de autoadensabilidade do concreto foram analisadas através dos ensaios de espalhamento, funil V e caixa L. No estado endurecido a resistência à compressão foi determinada. Os resultados mostraram que os diferentes procedimentos de execução do método não apresentaram divergências. O método da massa unitária mostrou-se eficiente na determinação de composições de agregado para atendimento ao CAA. Para um mesmo volume e composição de pasta (cimento, água, aditivos e adições) a composição quaternária foi a mais eficiente no atendimento às propriedades de autoadensabilidade e resistência à compressão.

Submitted by ANA FLÁVIA NUNES E REIS null (dra-anaflavia@uol.com.br) on 2016-01-26T19:16:31Z No. of bitstreams: 1 merged (4).pdf: 4937949 bytes, checksum: c052666784bd930ac4748e41040c73bd (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-01-28T13:31:20Z (GMT) No. of bitstreams: 1 reis_afn_me_sjc.pdf: 4937949 bytes, checksum: c052666784bd930ac4748e41040c73bd (MD5) / Made available in DSpace on 2016-01-28T13:31:20Z (GMT). No. of bitstreams: 1 reis_afn_me_sjc.pdf: 4937949 bytes, checksum: c052666784bd930ac4748e41040c73bd (MD5) Previous issue date: 2015-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi infiltrar sílica em uma cerâmica Y-TZP, avaliar seu efeito na resistência à flexão Biaxial, e na união com a porcelana feldspática. Para a análise da resistência à flexão foram confeccionados 180 discos de zircônia, 120 de 0,5mm e 60 com 1,2mm discos (14 mm de diâmetro). 90 discos foram infiltrados com sílica pelo método sol-gel em temperatura ambiente (n = 30). A espessura do disco foi de 1,2 mm para os espécimes controle (espécime sem porcelana, n = 30). O recobrimento por porcelana feldspática foi de duas espessuras (0,5mm e 1 mm) sobre a zircônia que tinha 0,5 mm. Os espécimes com porcelana foram polidos com lixas de carbeto de silício (SiC) de granulação # 400, 600, 800 e 1200. Obtivemos 6 grupos: dois monolíticos (ZR- Zircônia Monolítica sem infiltração e ZRI- Zircônia Monolítica Infiltrada) (controle) e quatro estratificados: ZRF 1,0 (0,5mm Zircônia coberta com 0,5 mm porcelana), ZRIF 1,0 (0,5 mm Zircônia infiltrada coberta com 0,5 mm de porcelana), ZRF 1,5 (0,5 mm Zircônia infiltrada coberta com 1,0 mm de porcelana) ZRIF 1,5- Zircônia infiltrada (0,5 mm Zircônia infiltrada coberta com 1,0 mm de porcelana). Após o ensaio de flexão biaxial em meio aquoso, foram determinados o módulo de Weibull (m) e resistência característica (σθ). Os fragmentos foram analisados em EDS, MEV, DRX e FTIR. A Dureza (H) e tenacidade a fratura foram analisadas pela nanoindentação, já o módulo elástico (E) por duas técnicas, nanoindentação e por impulso, e para avaliar a adesão entre a zircônia e a porcelana foi aplicado o Teste de Scratch. Foram modeladas 7 condições experimentais e analisados pelo método por elementos finitos. A zircônia monolítica infiltrada mostrou uma estrutura com grãos arredondados envoltos em uma matriz de sílica, e a presença de zircônia cúbica e tetragonal. O DRX revelou a formação de ZrSiO4 nos grupos infiltrados. Os grupos monolíticos apresentaram módulos de Weibull superiores aos dos grupos com porcelana. Com a análise (AEF) não houve diferença entre os grupos com a mesma espessura, já para o grupo recoberto com 0,5 mm de porcelana, os valores de tração e compressão foram maiores. A cerâmica infiltrada apresentou microestrutura diferente, e a adesão da porcelana à zircônia não-infiltrada foi superior à da zircônia infiltrada. / The objective was to infiltrate silica in a Y- TZP ceramics, evaluate its effect on resistance biaxial strenght, and the union with feldspathic porcelain. For the analysis of flexural strength were prepared zirconia discs 180, 120 and 60 of 0.5 mm to 1.2 mm disks (14 mm diameter). 90 discs were infiltrated with silica by the sol-gel method at room temperature (n = 30). The thickness of the disk was 1.2 mm for the samples control (no porcelain specimen, n = 30). The coating was feldspathic porcelain by two thicknesses (0.5 mm and 1 mm) of zirconia, which had 0.5 mm. Specimens with porcelain were polished with sandpaper silicon carbide (SiC) granulation # 400, 600, 800 and 1200. We obtained six groups: two monolithic (Zr-Zirconia Monolithic without infiltration and ZRI- Zirconia monolithic Infiltrated) (control) and four laminated ZRF 1.0 (0.5 mm zirconia covered with 0.5 mm porcelain), ZRIF 1.0 (0.5 mm infiltrated zirconia covered with 0.5 mm of porcelain), ZRF 1.5 (0.5 mm infiltrated zirconia covered with 1.0 mm of porcelain) ZRIF 1,5-infiltrated Zirconia (0.5 mm infiltrated zirconia covered with 1.0 mm of porcelain). After the biaxial bending test in an aqueous medium were determined Weibull modulus (m) and the characteristic strength (σθ). The fragments were analyzed by EDS, SEM, XRD and FTIR. The hardness (H) and fracture toughness were analyzed by nanoindentation, since the elastic modulus (E) by two techniques, nanoindentation and on impulse, and to evaluate the adhesion between the zirconia and porcelain was applied Scratch Test. 7 experimental conditions were modeled and analyzed by the finite element method. The infiltrated zirconia showed a monolithic structure with rounded grain wrapped in a silica matrix, and the presence of cubic and tetragonal zirconia. The XRD showed the formation of ZrSiO4 infiltrates in groups. The monolithic modules Weibull groups showed superior to porcelain groups. With the analysis (FEA) there was no difference between the groups with the same thickness, for now the group covered with 0.5 mm of porcelain, the tensile and compressive values were higher. The infiltrated ceramic showed different microstructure, and the accession of porcelain to non- infiltrated zirconia was higher than the infiltrated zirconia.