A laboratory testing program was conducted on cement-treated soil mixtures fabricated to represent materials produced by the wet method of deep mixing. The testing program focused on investigating the influences that variations in laboratory testing conditions and in the mix design have on measured property values. A base soil was fabricated from commercially available soil components to produce a very soft lean clay that is relatively easy to mix and can be replicated for future research. The mix designs included a range of water-to-cement ratios of the slurries and a range of cement factors to produce a range of mixture consistencies and a range of unconfined compressive strengths after curing. Unconfined compressive strength (UCS) tests and unconsolidated-undrained (UU) triaxial compression tests were conducted. Secant modulus of elasticity were determined from bottom platen displacements, deformations between bottom platen and cross bar, and from LVDT's placed directly on the cement-treated soil specimens. Five end-face treatment methods were used for the specimens: sawing-and-hand-trimming, machine grinding, sulfur capping, neoprene pads, and gypsum capping. Key findings of this research include the following: (1) The end-face treatment method does not have a significant effect on the unconfined compressive strength and secant modulus; (2) a relationship of UCS with curing time, total-water-to-cement ratio, and dry density of the mixture; (3) the secant modulus determined by bottom platen displacements is significantly affected by slack and deformations in the load frame; (4) the secant modulus determined by local strain measurements was about 630 time the UCS; (5) typical values of Poisson's ratio range from about 0.05 to 0.25 for stress levels equal to half the UCS and about 0.15 to 0.35 at the UCS; (6) Confinement increased the strength at high strains from less than 20% the UCS to about 60% the UCS. In addition to testing the cured mixtures, the consistency of the mixtures were measured right after mixing using a laboratory miniature vane. A combination of the UCS relationship along with the mixture consistency may provide useful information for deep mixing contractors. / MS / Deep mixing is a ground improvement technique that mixes cement with in-situ soil to improve the quality of the soil for supporting embankments, buildings, and other facilities. Deep mixing is also used for earth retention and to form subsurface seepage barriers. When the cement is added in dry powder form, the process is called the dry method of deep mixing, and when the cement is added in the form of cement-water slurry, the process is called the wet method of deep mixing. When using the wet method, both the water-to-cement ratio of the slurry and the amount of slurry added to the soil have important effects on the strength of the cured mixture. Laboratory mixtures are often tested in advance of field mixing to estimate the proportions of cement, water, and soil necessary to produce the desired outcomes. The laboratory test conditions influence the test results, and a wide variety of test conditions are used in practice. This research investigated different testing conditions and different mix designs to demonstrate their impacts on laboratory test results.

The Deep Mixing Method (DMM) is a widely used, in-situ ground improvement technique that modifies and improves the engineering properties of soil by blending the soil with a cementitious binder. Laboratory specimens were prepared to represent soil improved by the wet method of deep mixing, in which the binder is delivered in the form of a cement-water slurry. To study the influence of curing temperature on the strength of the treated soil, specimens were cured in temperature-controlled water baths for the desired curing time. After curing, unconfined compressive strength (UCS) tests were conducted on the specimens. To investigate the optimum mix design for the wet method of deep mixing, UCS tests were performed to measure the strength of cured specimens, and laboratory miniature vane shear tests were conducted on uncured specimens to measure the undrained shear strength (su), which is used to represent the consistency of the mixture right after mixing. The consistency is important for field mixing because a softer mixture is easier to mix thoroughly. Based on the UCS test results, an equation that can provide a good fit to the strength data of the cured binder-treated soil is proposed. When the curing temperature was changed during curing, the UCS of the specimen cured at a low temperature and then cured at a high temperature was greater than the UCS of the specimen cured at a high temperature first. This seems to be due to different effects of elevated curing temperatures at early and late curing times on the cement reaction rates, such that elevating the curing temperature later produces a more constant reaction rate, which contributes to the reaction efficiency. An optimum mix design that minimizes the amount of binder while satisfying both a target strength of the cured mixture and a target consistency of the uncured mixture can be established by using the fitted equations for UCS and su. The amount of binder required for the optimum mix design increases as the plasticity of the base soil increases and the water content of the base soil (wbase soil) decreases. / Master of Science / The Deep Mixing Method (DMM) is a ground improvement technique widely used to improve the strength and stiffness of loose sands, soft clays, and organic soils. The DMM is useful for both inland and coastal construction. There are two types of deep mixing. The dry method of deep mixing involves adding the binder in the form of dry powder, and the wet method of deep mixing involves mixing binder-water slurry with the soil. The strength of the cured mixture is significantly influenced by the amount of added cement and water, the curing time, and the curing temperature. This research evaluates the influence of curing temperature on the strength of cured cement-treated soil mixture. Mixture proportions and curing conditions also influence the consistency of the mixture right after mixing, which is important because it affects the amount of mixing energy necessary to thoroughly mix the binder slurry with the soil. This research developed and evaluated fitting equations that correlate the cured mixture strength and the uncured mixture consistency with mixture proportions and curing conditions. These fitting equations can then be used to select an economical and practical mix design method that minimizes the amount of binder needed to achieve both the desired cured strength and uncured consistency. The amount of binder required for the optimum mix design increases as the plasticity of the base soil increases and the water content of the base soil (wbase soil) decreases.

Nos últimos anos, intensos estudos vêm sendo realizados no que se refere a substitutos ósseos biocompatíveis e absorvíveis, notadamente os cimentos ósseos de fosfato de cálcio, para cirurgias de reconstrução e em engenharia de tecidos. Porém os cimentos de fosfato de cálcio desenvolvidos apresentam baixa resistência mecânica quando comparados com os ossos do corpo humano. Neste contexto, a busca por alternativas para minimizar esse problema tem se intensificado. A obtenção de alfa-fosfato tricálcico por outras rotas de síntese, bem como o desenvolvimento de compósitos de fosfatos de cálcio e hidrogéis têm se destacado nesse ramo. O preparo destes compósitos permite combinar excelentes propriedades como: i) osteocondutividade e capacidade de formar ligações com o tecido ósseo proporcionado pelos fosfatos de cálcio e ii) facilidade de adesão e distribuição de células no interior de scaffolds, proporcionado pelo hidrogel. O objetivo do presente trabalho foi o desenvolvimento de uma nova metodologia de obtenção de alfa-fosfato tricálcico, o preparo de composições de cimentos de fosfato de cálcio e de hidrogéis, bem como a obtenção e caracterização de compósitos destes, visando o melhoramento das propriedades para aplicação como biomaterial Foi possível sintetizar alfa-fosfato tricálcico com elevado grau de pureza, utilizando-se o método de reação via úmida. Após estudos da ordem de adição e concentração dos reagentes foi possível definir os melhores parâmetros de síntese. Com isso verificou-se a influência do tempo de moagem nas propriedades dos cimentos, sendo constatado que para o fosfato de cálcio preparado pela metodologia proposta, não há necessidade de moagem adicional. Foram testadas formulações de hidrogéis utilizando N-vinil-2-pirrolidona e ou ácido acrílico, utilizando três iniciadores: azobisisobutironitrila, persulfato de amônio e 1- hidroxiciclohexil fenil cetona. Pela adição de formulações de hidrogéis ao cimento foi possível obter compósitos com maior absorção de água, mantendo as propriedades mecânicas, o que pode permitir uma melhor adesão celular ao implante sem comprometer sua estrutura. O ensaio de citotoxicidade in vitro demonstrou que o cimento sintetizado neste trabalho não apresentou efeito tóxico para as células. Mostrando, ainda, a adesão e proliferação de célulastronco mesenquimais e de uma linhagem de osteoblastos. / In the last years, intensive studies have been conducted regarding the biocompatible and resorbable bone substitutes, notably calcium phosphate bone cements, for reconstructive surgery and tissue engineering. However, the calcium phosphate cements developed exhibit low mechanical strength when compared with the bones of the human body. In this context, the search for alternatives to minimize this problem has intensified. The obtaining of alphatricalcium phosphate by others synthesis routes, as well as development of calcium phosphate and hydrogels composites has been prominent in this branch. The preparation of these composites allows to combine excellent properties such as: i) osteoconductivity and ability to form bonds with bone tissue, afforded by calcium phosphate and ii) ease of adhesion and distribution of cells in the scaffolds inside, provided by hydrogel. The aim of this work was the development of a new methodology to obtaining alpha-tricalcium phosphate, the preparation of calcium phosphate cements and hydrogels compositions, as well as the obtaining and characterization of composites of these, intended to improve the properties for application as biomaterial. It was possible to synthesize alpha-tricalcium phosphate with high purity using the wet method reaction After studies of the addition order and reagents concentration was possible to define the best synthesis parameters. With that it was verified the influence of milling time on the cements properties to being noted that for the calcium phosphate prepared by the proposed method, there is no need additional milling. Were tested hydrogel formulations using N-vinyl-2-pyrrolidone and/or acrylic acid, using three initiators: azobisisobutyronitrile, ammonium persulfate and 1-hydroxycyclohexyl phenyl ketone. By the addition of the hydrogel formulations to the cement was possible to obtain composites with higher water absorption by keeping the mechanical properties, which may permits better vascularization of the implant without compromising its structure. The in vitro cytotoxicity assay demonstrated that the cement synthesized in this work does not show any toxic effect on the cells. Also, showing the adhesion and proliferation of mesenchymal stem cells and an osteoblast line.

Nos últimos anos, intensos estudos vêm sendo realizados no que se refere a substitutos ósseos biocompatíveis e absorvíveis, notadamente os cimentos ósseos de fosfato de cálcio, para cirurgias de reconstrução e em engenharia de tecidos. Porém os cimentos de fosfato de cálcio desenvolvidos apresentam baixa resistência mecânica quando comparados com os ossos do corpo humano. Neste contexto, a busca por alternativas para minimizar esse problema tem se intensificado. A obtenção de alfa-fosfato tricálcico por outras rotas de síntese, bem como o desenvolvimento de compósitos de fosfatos de cálcio e hidrogéis têm se destacado nesse ramo. O preparo destes compósitos permite combinar excelentes propriedades como: i) osteocondutividade e capacidade de formar ligações com o tecido ósseo proporcionado pelos fosfatos de cálcio e ii) facilidade de adesão e distribuição de células no interior de scaffolds, proporcionado pelo hidrogel. O objetivo do presente trabalho foi o desenvolvimento de uma nova metodologia de obtenção de alfa-fosfato tricálcico, o preparo de composições de cimentos de fosfato de cálcio e de hidrogéis, bem como a obtenção e caracterização de compósitos destes, visando o melhoramento das propriedades para aplicação como biomaterial Foi possível sintetizar alfa-fosfato tricálcico com elevado grau de pureza, utilizando-se o método de reação via úmida. Após estudos da ordem de adição e concentração dos reagentes foi possível definir os melhores parâmetros de síntese. Com isso verificou-se a influência do tempo de moagem nas propriedades dos cimentos, sendo constatado que para o fosfato de cálcio preparado pela metodologia proposta, não há necessidade de moagem adicional. Foram testadas formulações de hidrogéis utilizando N-vinil-2-pirrolidona e ou ácido acrílico, utilizando três iniciadores: azobisisobutironitrila, persulfato de amônio e 1- hidroxiciclohexil fenil cetona. Pela adição de formulações de hidrogéis ao cimento foi possível obter compósitos com maior absorção de água, mantendo as propriedades mecânicas, o que pode permitir uma melhor adesão celular ao implante sem comprometer sua estrutura. O ensaio de citotoxicidade in vitro demonstrou que o cimento sintetizado neste trabalho não apresentou efeito tóxico para as células. Mostrando, ainda, a adesão e proliferação de célulastronco mesenquimais e de uma linhagem de osteoblastos. / In the last years, intensive studies have been conducted regarding the biocompatible and resorbable bone substitutes, notably calcium phosphate bone cements, for reconstructive surgery and tissue engineering. However, the calcium phosphate cements developed exhibit low mechanical strength when compared with the bones of the human body. In this context, the search for alternatives to minimize this problem has intensified. The obtaining of alphatricalcium phosphate by others synthesis routes, as well as development of calcium phosphate and hydrogels composites has been prominent in this branch. The preparation of these composites allows to combine excellent properties such as: i) osteoconductivity and ability to form bonds with bone tissue, afforded by calcium phosphate and ii) ease of adhesion and distribution of cells in the scaffolds inside, provided by hydrogel. The aim of this work was the development of a new methodology to obtaining alpha-tricalcium phosphate, the preparation of calcium phosphate cements and hydrogels compositions, as well as the obtaining and characterization of composites of these, intended to improve the properties for application as biomaterial. It was possible to synthesize alpha-tricalcium phosphate with high purity using the wet method reaction After studies of the addition order and reagents concentration was possible to define the best synthesis parameters. With that it was verified the influence of milling time on the cements properties to being noted that for the calcium phosphate prepared by the proposed method, there is no need additional milling. Were tested hydrogel formulations using N-vinyl-2-pyrrolidone and/or acrylic acid, using three initiators: azobisisobutyronitrile, ammonium persulfate and 1-hydroxycyclohexyl phenyl ketone. By the addition of the hydrogel formulations to the cement was possible to obtain composites with higher water absorption by keeping the mechanical properties, which may permits better vascularization of the implant without compromising its structure. The in vitro cytotoxicity assay demonstrated that the cement synthesized in this work does not show any toxic effect on the cells. Also, showing the adhesion and proliferation of mesenchymal stem cells and an osteoblast line.

Nos últimos anos, intensos estudos vêm sendo realizados no que se refere a substitutos ósseos biocompatíveis e absorvíveis, notadamente os cimentos ósseos de fosfato de cálcio, para cirurgias de reconstrução e em engenharia de tecidos. Porém os cimentos de fosfato de cálcio desenvolvidos apresentam baixa resistência mecânica quando comparados com os ossos do corpo humano. Neste contexto, a busca por alternativas para minimizar esse problema tem se intensificado. A obtenção de alfa-fosfato tricálcico por outras rotas de síntese, bem como o desenvolvimento de compósitos de fosfatos de cálcio e hidrogéis têm se destacado nesse ramo. O preparo destes compósitos permite combinar excelentes propriedades como: i) osteocondutividade e capacidade de formar ligações com o tecido ósseo proporcionado pelos fosfatos de cálcio e ii) facilidade de adesão e distribuição de células no interior de scaffolds, proporcionado pelo hidrogel. O objetivo do presente trabalho foi o desenvolvimento de uma nova metodologia de obtenção de alfa-fosfato tricálcico, o preparo de composições de cimentos de fosfato de cálcio e de hidrogéis, bem como a obtenção e caracterização de compósitos destes, visando o melhoramento das propriedades para aplicação como biomaterial Foi possível sintetizar alfa-fosfato tricálcico com elevado grau de pureza, utilizando-se o método de reação via úmida. Após estudos da ordem de adição e concentração dos reagentes foi possível definir os melhores parâmetros de síntese. Com isso verificou-se a influência do tempo de moagem nas propriedades dos cimentos, sendo constatado que para o fosfato de cálcio preparado pela metodologia proposta, não há necessidade de moagem adicional. Foram testadas formulações de hidrogéis utilizando N-vinil-2-pirrolidona e ou ácido acrílico, utilizando três iniciadores: azobisisobutironitrila, persulfato de amônio e 1- hidroxiciclohexil fenil cetona. Pela adição de formulações de hidrogéis ao cimento foi possível obter compósitos com maior absorção de água, mantendo as propriedades mecânicas, o que pode permitir uma melhor adesão celular ao implante sem comprometer sua estrutura. O ensaio de citotoxicidade in vitro demonstrou que o cimento sintetizado neste trabalho não apresentou efeito tóxico para as células. Mostrando, ainda, a adesão e proliferação de célulastronco mesenquimais e de uma linhagem de osteoblastos. / In the last years, intensive studies have been conducted regarding the biocompatible and resorbable bone substitutes, notably calcium phosphate bone cements, for reconstructive surgery and tissue engineering. However, the calcium phosphate cements developed exhibit low mechanical strength when compared with the bones of the human body. In this context, the search for alternatives to minimize this problem has intensified. The obtaining of alphatricalcium phosphate by others synthesis routes, as well as development of calcium phosphate and hydrogels composites has been prominent in this branch. The preparation of these composites allows to combine excellent properties such as: i) osteoconductivity and ability to form bonds with bone tissue, afforded by calcium phosphate and ii) ease of adhesion and distribution of cells in the scaffolds inside, provided by hydrogel. The aim of this work was the development of a new methodology to obtaining alpha-tricalcium phosphate, the preparation of calcium phosphate cements and hydrogels compositions, as well as the obtaining and characterization of composites of these, intended to improve the properties for application as biomaterial. It was possible to synthesize alpha-tricalcium phosphate with high purity using the wet method reaction After studies of the addition order and reagents concentration was possible to define the best synthesis parameters. With that it was verified the influence of milling time on the cements properties to being noted that for the calcium phosphate prepared by the proposed method, there is no need additional milling. Were tested hydrogel formulations using N-vinyl-2-pyrrolidone and/or acrylic acid, using three initiators: azobisisobutyronitrile, ammonium persulfate and 1-hydroxycyclohexyl phenyl ketone. By the addition of the hydrogel formulations to the cement was possible to obtain composites with higher water absorption by keeping the mechanical properties, which may permits better vascularization of the implant without compromising its structure. The in vitro cytotoxicity assay demonstrated that the cement synthesized in this work does not show any toxic effect on the cells. Also, showing the adhesion and proliferation of mesenchymal stem cells and an osteoblast line.

This thesis deals with interaction of microwave radiation with wet in porous material. It examines the distribution of the temperature field, the efficiency of the method and the financial demands of the method. The most important part of this thesis was an experiment, from which all important values ??were based. The first part deals with the necessary theory and the second part is the experiment itself. The experiment was carried out for three levels of material wet. Eight samples were used for this experiment, which remained unchanged throughout the experiment. The thesis draws on previous researches that were carried out on this or similar topic.