No description available.

Made available in DSpace on 2014-06-11T19:25:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-09-24Bitstream added on 2014-06-13T20:32:46Z : No. of bitstreams: 1 berte_sdd_me_ilha.pdf: 1473291 bytes, checksum: 61382a3a1bac42cdf44d0975ecac5ff5 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esta dissertação trata de uma pesquisa sobre a otimização e o comportamento do SCAA – Solo-Cimento Auto-Adensável tanto no seu estado fresco quanto no seu estado endurecido, confeccionando-se misturas com variação nos teores de cimento, água e aditivo superplastificante. A proposta visa analisar e compreender os desafios de se obter a auto- adensabilidade em misturas de solo-cimento, bem como o comportamento deste material no que diz respeito aos finos do solo e o cimento frente à água, envolvendo a coesão ou dispersão das partículas de solo, na tentativa de determinar qualitativamente ou quantitativamente a fluidez, a homogeneidade, a exsudação, a segregação, a resistência à compressão mecânica e a absorção de água do material. A pesquisa foi dividida em três etapas, sendo elas: o Estudo Preliminar (EP) que contou com 5 misturas, o Estudo de Otimização (EO) que contou com 27 misturas e o Estudo de Aperfeiçoamento (EA). No EP e no EO, com o material no estado fresco, foram efetuados os ensaios do Funil, de Espalhamento, de Segregação e de Adensamento e Moldagem em corpos-de-provas cilíndricos de 5 cm de diâmetro e 10 cm de altura e em formato de estrelas. No EO, os cilindros, no estado endurecido, foram submetidos a ensaios de Resistência à Compressão Mecânica e Absorção de Água, sendo que os resultados de resistência à compressão mecânica de todas as misturas apresentaram valores entre 2,0 e 7,5 MPa, atendendo assim a norma de solo-cimento; e quanto aos valores obtidos de absorção de água, 3 das 27 misturas apresentaram valores superiores ao que a norma estipula como máximo de 20% e as demais misturas apresentaram valores bem inferiores a este. No EA, foi eleita a mistura otimizada, sendo esta repetida e, com ela, confeccionados 20... / This paper is a study on the optimization and behavior of SCSC – Self-Compacting Soil Cement both in its fresh state as in its hardened state, using mixtures with variation in levels of cement, water and superplasticizer. The proposals are to analyze and understand the challenges of attaining a self-compacting soil cement as to understand the behavior of this material, especially the fine part of the soil and cement plus water, involving the cohesion or dispersion of the particles of the soil, in an attempt to determine the flowability, homogeneity, exudation, segregation, the mechanical compressive strength and the water absorption of the material. The research was divided into three stages: the Preliminary Study (PS), which featured five mixtures, the Study of Optimization (SO), which included 27 mixtures, and the Study and Improvement (SI). In PS and SO, during the fresh state of the material, there were performed the tests of Funnel, Scattering, Segregation and molding cylinders of 5 cm in diameter and 10 cm height and some in shape of stars. In the SO, the cylinders, in the hardened state, were tested for compressive strength and water absorption. The results of mechanical compression resistance of all blends showed values between 2.0 and 7.5 MPa, thus according to the standard of soil-cement. On the water absorption test, 3 of the 27 mixtures showed higher values than the standard provides (a maximum of 20%) and the other mixtures showed values well below this. In the SI, the mixture with better results on the tests was selected. With this mixture, it was made 20 cylinders of 5 cm diameter and 10 cm in height, which were tested for compressive strength. Also in SI, the selected mixture was again repeated. This time it was used to assess the feasibility of gravity flow through the passage of the mixture through a funnel... (Complete abstract click electronic access below)

abstract: The main objective of this study is to investigate the effect of polypropylene fiber morphology on the tensile response of cementitious composites. Two proprietary polypropylene fibers manufactured by BASF – MAC 2200CB, a crimped monofilament macro fiber and MF40, a bundled multi filament polypropylene made up of 500 filaments,40-micron diameter each were compared. The stiff structure and crimped geometry of MAC 2200 CB was studied in comparison with the multifilament MF40, which provide a higher surface area and a bundled fiber effect. Uniaxial tensile tests were performed on individual fibers to study fiber strength and failure pattern at three different gage lengths. The interaction of these 2 fibers with cement matrix was studied under varying strain rate, embedded fiber length and matrix mixes by a series of quassi - static fiber pullout tests. Unidirectional filament wound composite laminates were manufactures with the two fibers and only MF40 woven textiles were used to manufacture MF40 textile reinforced composites. The mechanical behavior of polypropylene fiber and textile reinforced cementitious composites subjected to static tensile loading with the effects of fiber type and dosage, textile weave and dosage, matrix formulations, processing techniques etc. is studied. Evolution of distributed cracking mechanism and local strain fields was documented using digital image correlation (DIC) and correlated with the tensile response and stiffness degradation. VIC 3D-7, commercial software developed by Correlated Solutions, Inc. was used to run the DIC analysis for the tensile tests on laminates. The DIC technique was further used for automated determination of crack density, crack spacing, and characterizing damage evolution. / Dissertation/Thesis / Masters Thesis Civil Engineering 2017

Made available in DSpace on 2014-06-11T19:27:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-25Bitstream added on 2014-06-13T20:56:54Z : No. of bitstreams: 1 mata_m_me_arafo.pdf: 873853 bytes, checksum: 871f78b9e17a3ffeb34d531adfa84d2f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste estudo foi avaliar in vitro o efeito da aplicação do ultrassom (US) na produção de calor na superfície e no interior do cimento de ionômero de vidro (CIV) Ketac Molar Easymix, assim como a temperatura transmitida à câmara pulpar através de restaurações de Ketac Molar Easymix (K) e Vitremer (V) após aplicação de US. Para avaliação da temperatura interna e superficial foi confeccionada uma matriz a partir de um incisivo bovino. A temperatura superficial foi aferida no grupo controle (TSC) e no grupo experimental (TSU) por meio de uma câmera termográfica infravermelha, calibrada e fixada há 15 cm do espécime, a qual captou as variações de temperatura por 80s. Para aferir a temperatura no interior do material, uma cânula de nylon foi inserida via abertura do conduto radicular do dente bovino até atingir o interior do CIV inserido na matriz, na qual foi adaptado um termômetro de vareta digital portátil. Após US por 45s, nos grupos controle (TIC) e experimental (TIU), a temperatura interna foi aferida em 0, 45, e 120s, totalizando 2 min após a inserção do material na cavidade. A temperatura transmitida à câmara pulpar durante a aplicação de US por 45s foi avaliada em 48 pré-molares humanos, os quais tiveram seus ápices seccionados para remoção da polpa, substituída por uma pasta condutora de calor. Foram divididos nos grupos: controle (KC), experimental (KU), controle (VC) e experimental (VU). Após a realização das restaurações na face vestibular dos dentes, estas receberam a aplicação de US por 45s e fotopolimerização por 40s para o grupo VU. Através da abertura dos condutos radiculares dos dentes, um termístor foi inserido até entrar em contato com a parede interna da superfície vestibular, possibilitando a captação... / The aim of this study was to evaluate in vitro the effect of ultrasound (US) application in the production of heat at the surface and inside the glass ionomer cement (GIC) Ketac Molar Easymix, as well the temperature transmitted to the pulp chamber through restorations of Ketac Molar Easymix (K) and Vitremer (V) after ultrasound application. For evaluation of the internal and surface temperature was made a matrix of one bovine incisor. The surface temperature was measured in the control group (STC) and the experimental group (STU) through an infrared thermographic camera, calibrated and fixed for 15 cm of the specimen, which raised the temperature variations for 80s. In order to measure the temperature inside the material, a nylon cannula was inserted through opening of the root canal bovine tooth until the interior of the GIC inserted into the array, which was adapted an portable digital thermometer. After US for 45s, in the control group (ITC) and experimental group (ITU), the internal temperature was measured at 0, 45, and 120s, totaling 2 minutes after material insertion in the cavity. The temperature transmitted to the pulp chamber during the application of ultrasound for 45s was evaluated in 48 human premolars, which had their apices disconnected to remove the pulp, replaced by a heat-conductive paste. They were divided into groups: control (KC), experimental (KU), control (VC) and experimental (VU). After performing of the restorations on the vestibular surface of the teeth, they received the ultrasound application for 45s and photopolymerization for 40s for the group VU. Through the opening of the root canal tooth, a thermistor was inserted until contact with the inner wall of the vestibular surface, allowing the collection of temperature variations. After verification of normality in the STC, STU, ITC, ITU groups... (Complete abstract click electronic access below)

Orientador: Angela Cristina Cilense Zuanon / Banca: Renata Cristiane da Silva / Banca: Ticiane Sidorenko de Oliveira Capote / Resumo: O objetivo deste estudo foi avaliar in vitro o efeito da aplicação do ultrassom (US) na produção de calor na superfície e no interior do cimento de ionômero de vidro (CIV) Ketac Molar Easymix, assim como a temperatura transmitida à câmara pulpar através de restaurações de Ketac Molar Easymix (K) e Vitremer (V) após aplicação de US. Para avaliação da temperatura interna e superficial foi confeccionada uma matriz a partir de um incisivo bovino. A temperatura superficial foi aferida no grupo controle (TSC) e no grupo experimental (TSU) por meio de uma câmera termográfica infravermelha, calibrada e fixada há 15 cm do espécime, a qual captou as variações de temperatura por 80s. Para aferir a temperatura no interior do material, uma cânula de nylon foi inserida via abertura do conduto radicular do dente bovino até atingir o interior do CIV inserido na matriz, na qual foi adaptado um termômetro de vareta digital portátil. Após US por 45s, nos grupos controle (TIC) e experimental (TIU), a temperatura interna foi aferida em 0, 45, e 120s, totalizando 2 min após a inserção do material na cavidade. A temperatura transmitida à câmara pulpar durante a aplicação de US por 45s foi avaliada em 48 pré-molares humanos, os quais tiveram seus ápices seccionados para remoção da polpa, substituída por uma pasta condutora de calor. Foram divididos nos grupos: controle (KC), experimental (KU), controle (VC) e experimental (VU). Após a realização das restaurações na face vestibular dos dentes, estas receberam a aplicação de US por 45s e fotopolimerização por 40s para o grupo VU. Através da abertura dos condutos radiculares dos dentes, um termístor foi inserido até entrar em contato com a parede interna da superfície vestibular, possibilitando a captação... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate in vitro the effect of ultrasound (US) application in the production of heat at the surface and inside the glass ionomer cement (GIC) Ketac Molar Easymix, as well the temperature transmitted to the pulp chamber through restorations of Ketac Molar Easymix (K) and Vitremer (V) after ultrasound application. For evaluation of the internal and surface temperature was made a matrix of one bovine incisor. The surface temperature was measured in the control group (STC) and the experimental group (STU) through an infrared thermographic camera, calibrated and fixed for 15 cm of the specimen, which raised the temperature variations for 80s. In order to measure the temperature inside the material, a nylon cannula was inserted through opening of the root canal bovine tooth until the interior of the GIC inserted into the array, which was adapted an portable digital thermometer. After US for 45s, in the control group (ITC) and experimental group (ITU), the internal temperature was measured at 0, 45, and 120s, totaling 2 minutes after material insertion in the cavity. The temperature transmitted to the pulp chamber during the application of ultrasound for 45s was evaluated in 48 human premolars, which had their apices disconnected to remove the pulp, replaced by a heat-conductive paste. They were divided into groups: control (KC), experimental (KU), control (VC) and experimental (VU). After performing of the restorations on the vestibular surface of the teeth, they received the ultrasound application for 45s and photopolymerization for 40s for the group VU. Through the opening of the root canal tooth, a thermistor was inserted until contact with the inner wall of the vestibular surface, allowing the collection of temperature variations. After verification of normality in the STC, STU, ITC, ITU groups... (Complete abstract click electronic access below) / Mestre

Orientador: Marco Antonio de Morais Alcântara / Coorientador: Antonio Anderson da Silva Segantini / Banca: Sergio Augusto Mello da Silva / Banca: Obede Borges Faria / Resumo: Esta dissertação trata de uma pesquisa sobre a otimização e o comportamento do SCAA - Solo-Cimento Auto-Adensável tanto no seu estado fresco quanto no seu estado endurecido, confeccionando-se misturas com variação nos teores de cimento, água e aditivo superplastificante. A proposta visa analisar e compreender os desafios de se obter a auto- adensabilidade em misturas de solo-cimento, bem como o comportamento deste material no que diz respeito aos finos do solo e o cimento frente à água, envolvendo a coesão ou dispersão das partículas de solo, na tentativa de determinar qualitativamente ou quantitativamente a fluidez, a homogeneidade, a exsudação, a segregação, a resistência à compressão mecânica e a absorção de água do material. A pesquisa foi dividida em três etapas, sendo elas: o Estudo Preliminar (EP) que contou com 5 misturas, o Estudo de Otimização (EO) que contou com 27 misturas e o Estudo de Aperfeiçoamento (EA). No EP e no EO, com o material no estado fresco, foram efetuados os ensaios do Funil, de Espalhamento, de Segregação e de Adensamento e Moldagem em corpos-de-provas cilíndricos de 5 cm de diâmetro e 10 cm de altura e em formato de estrelas. No EO, os cilindros, no estado endurecido, foram submetidos a ensaios de Resistência à Compressão Mecânica e Absorção de Água, sendo que os resultados de resistência à compressão mecânica de todas as misturas apresentaram valores entre 2,0 e 7,5 MPa, atendendo assim a norma de solo-cimento; e quanto aos valores obtidos de absorção de água, 3 das 27 misturas apresentaram valores superiores ao que a norma estipula como máximo de 20% e as demais misturas apresentaram valores bem inferiores a este. No EA, foi eleita a mistura otimizada, sendo esta repetida e, com ela, confeccionados 20... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This paper is a study on the optimization and behavior of SCSC - Self-Compacting Soil Cement both in its fresh state as in its hardened state, using mixtures with variation in levels of cement, water and superplasticizer. The proposals are to analyze and understand the challenges of attaining a self-compacting soil cement as to understand the behavior of this material, especially the fine part of the soil and cement plus water, involving the cohesion or dispersion of the particles of the soil, in an attempt to determine the flowability, homogeneity, exudation, segregation, the mechanical compressive strength and the water absorption of the material. The research was divided into three stages: the Preliminary Study (PS), which featured five mixtures, the Study of Optimization (SO), which included 27 mixtures, and the Study and Improvement (SI). In PS and SO, during the fresh state of the material, there were performed the tests of Funnel, Scattering, Segregation and molding cylinders of 5 cm in diameter and 10 cm height and some in shape of stars. In the SO, the cylinders, in the hardened state, were tested for compressive strength and water absorption. The results of mechanical compression resistance of all blends showed values between 2.0 and 7.5 MPa, thus according to the standard of soil-cement. On the water absorption test, 3 of the 27 mixtures showed higher values than the standard provides (a maximum of 20%) and the other mixtures showed values well below this. In the SI, the mixture with better results on the tests was selected. With this mixture, it was made 20 cylinders of 5 cm diameter and 10 cm in height, which were tested for compressive strength. Also in SI, the selected mixture was again repeated. This time it was used to assess the feasibility of gravity flow through the passage of the mixture through a funnel... (Complete abstract click electronic access below) / Mestre

No description available.

Este trabalho propõe contribuir no desenvolvimento do processo de extrusão para a produção de compósitos cimentícios, mediante metodologia que possibilite a obtenção de formulações extrudáveis utilizando cimento Portland de alta resistência inicial, sílica ativa, calcário, polpa de celulose de eucalipto, fibras de polipropileno e aditivos. Para isso, foram caracterizadas as matérias-primas como subsidio para as discussões. O efeito dos diferentes componentes da formulação no comportamento reológico da mistura foi avaliado utilizando reômetro extrusor. As propriedades físicas e mecânicas dos compósitos elaborados com combinações de calcário, sílica ativa e cimento foram modeladas estatisticamente com o propósito de estimar o comportamento das matrizes. A demanda de água dos sistemas cimentícios foi determinada experimentalmente e utilizada na extrusão das matrizes. Selecionada uma matriz, suas propriedades mecânicas e físicas foram modeladas, estatisticamente, com diferentes teores de polpa celulósica de eucalipto e fibras de polipropileno. As formulações com características desejadas foram avaliadas ao envelhecimento acelerado por 200 ciclos de imersão-secagem. Finalmente foi analisada a reprodutibilidade utilizando o módulo de Weibull para as formulações selecionadas. O estudo reológico constatou que as fibras de polipropileno apresentam os maiores aumentos nos valores dos parâmetros reológicos se comparados com os efeitos do calcário, sílica ou celulose de eucalipto, repercutindo em maiores pressões de extrusão. O incremento do modificador reológico hidroxipropilmetilcelulose reduz no compósito cimentício o módulo de ruptura mesmo que durante o processamento, promova o incremento da pressão de extrusão. Os modelos estatísticos empregados para modelar a matriz reforçada foram de maior complexidade e com menor coeficiente de determinação se comparados com os utilizados na modelagem das matrizes. O preço de mercado do fibrocimento é aproximadamente 64% menor do que os determinados utilizando unicamente os valores das matérias-primas e aditivos do fibrocimento extrudado no presente estudo. / This work intends to contribute in the development of the extrusion process for the production of cementitious composites, through methodology that makes it possible to obtain formulas using high resistance Portland cement, silica fume, limestone, eucalyptus pulp, polypropylene fibers and admixtures. With this intention, the raw materials were characterized as a support for the discussions. The effects of the different components of the formula on the rheological behavior of the mixture were evaluated using an extrusion rheometer. The physical and mechanical properties of the composites elaborated with the combinations of limestone, silica fume and cement were modeled statistically with the purpose of estimating the behavior of the matrix. The water demand of the cementitious systems was determined experimentally and used in the matrixes extrusion. After the Matrix Selection, their mechanical and physical properties were modeled statistically, with different pulp eucalyptus and polypropylene fibers quantities. The formulas with the expected characteristics were evaluated to the accelerated aging for 200 wet-drying cycles. Finally the reproducibility was analyzed using the Weibull module for the selected formulas. The rheological studies verified that the polypropylene fibers demonstrate the largest increase in the values of the rheological parameters when compared with the effects of the limestone, silica fume or eucalyptus pulp, inducing larger extrusion pressures. The increment of the rheological modifier hydroxypropyl methylcellulose decreases the module of rupture in the cementitious composite, and simultaneously during the process it promotes the increment of the extrusion pressure. The statistical models used to reinforce the matrix modeling were of large complexity and with smaller coefficient determination when compared to matrixes used for modeling. The fiber cement market price is approximately 64% smaller than the raw materials and admixtures used in extruded fiber cement in this study.

Cutter Soil Mixing (CSM) is a recently developed deep mixing technique that has grown to include the treatment of sandy and silty soils. This study seeks to investigate the influence of (i) sand-silt ratio, (ii) cement content, (iii) water content and (iv) time on the unconfined compressive strength of saturated cement-treated soil specimens. A new test device and method of specimen reconstitution were conceived in order to obtain a saturated mix of soil and cement. A comparison of results show strength increases non-linearly to decreasing total water-cement ratio, and that this trend is largely independent of sand-silt ratio. Furthermore, strength increases non-linearly with time and is independent of sand-silt ratio. Lastly, it is recommended that the strength be correlated with total water-cement ratio rather than cement content, in order to improve data reporting and provide design guidance to engineering practice. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

This thesis presents two separate applications of ionising radiation in Civil Engineering. The first is an investigation to determine the cement content of concrete using gamma-rays from the naturally occurring isotopes 238U, 232Th and their decay chains as well as 40K. Two sets of equations are derived and discussed. Spectra from cement, aggregate and concrete samples were made and the useful full energy peaks from the above sources identified. Two concrete samples were prepared using the same cement, but, containing two different aggregates: a granite based aggregate and a flint based aggregate. A third concrete sample was then prepared where the cement content was not initially known. Data from the first two tests was then used to determine the mass of cement used in the blind test. A great deal of valuable information has also been accrued concerning the interaction of statistical errors in the equations for the prediction of cement content. Spectra from four different cements were collected at regular intervals over a 24 month period and the variation in the activity of each cement over this period is discussed. The second section of this work presents an imaging technique that uses pair production annihilation photons to examine the state of steel reinforcement in concrete structures. Computer simulations along with experimental work have been used. The experimental work used a 226Ra needle as a photon source as it provided a range of gamma-rays with energies over the pair production threshold of 1022keV. A 31mm rebar with 30mm of concrete cover was successfully located during the experimental work. The data collected from the computer simulations has shown that the geometry and the material between the photon source, rebar and detector is of great importance.