Thesis (Ph. D.). UM #74-17,941. / Title from document title page. Includes bibliographical references. Available in PDF format via the World Wide Web.

Thesis (M.S.); Submitted to Iowa State Univ., Ames, IA (US); 12 Dec 2003. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2608" Maria Ambert Sanchez. 12/12/2003. Report is also available in paper and microfiche from NTIS.

Mémoire (M.Eng.)--Université du Québec à Chicoutimi, 1994. / Résumé disponible sur Internet. CaQCU Document électronique également accessible en format PDF. CaQCU

Made available in DSpace on 2014-12-17T14:06:49Z (GMT). No. of bitstreams: 1 MauricioRP.pdf: 769557 bytes, checksum: 64ad674a4bbb41883e038d57b445215c (MD5) Previous issue date: 2008-11-10 / Lightweight concrete has been the subject of several studies towards the development of new building materials. Emphasis has been given on the particle size effect and nature of aggregates used as raw materials. The present study includes an analysis of the materials that make this kind of concrete, analyzes of mechanical properties such as compressive and tensile strength, in addition to assessments of the interface concrete aggregate/matrix interface, porosity and absorption profile of chloride ions in lightweight concrete based on expanded clay. The experiments were carried out by molding cylindrical samples 100 mm in diameter and 200 mm in height. The dosage experiments were performed without additives or with the addition of minerals: (T1) 1: 2.01: 1.10: 0.78 (T2) 1: 2.00: 1.32 : 0.62 - (T3) 1 :1.93 :1.54: 0.47 (cement : sand : expanded clay 0500 : expanded clay 1506).The water to cement ratio was set to 0.43. Expanded clay minerals with different average particle sizes were used, i.e., 9.5 mm/0500 and 19 mm/1506. The larger aggregate was coated by a glassy layer, yielding lower water absorption characteristics to the concrete. The results showed that the use of light expanded clay aggregates is a technically interesting solution to the production of lightweight concrete for construction applications / Considerando-se as tend?ncias de novos materiais na Constru??o Civil, o concreto leve tem sido objeto de v?rios trabalhos, com ?nfase na granulometria e suas mat?rias primas. Incluem-se neste estudo a altera??o de tra?os e dos materiais que comp?em esse concreto, analisando altera??es nas propriedades mec?nicas como resist?ncia ? compress?o e tra??o por compress?o diametral, al?m da interface agregado/matriz, porosidade e perfil de absor??o de ?ons cloreto no concreto leve ? base de argila expandida. Os experimentos foram realizados atrav?s de moldagem de corpos de prova cil?ndricos, com 100 mm de di?metro e 200 mm de altura. A dosagem experimental foi efetuada sem aditivos ou adi??es minerais, nos tra?os unit?rios em massa: (T1) 1 : 2,01 : 1,10 : 0,78 (T2) 1 : 2,00 : 1,32 : 0,62 - (T3) 1 : 1,93 : 1,54 : 0,47 (cimento : areia : argila expandida 0500 : argila expandida 1506); fixando-se a rela??o ?gua/cimento em 0,43. Para tanto, utilizou-se como agregado gra?do uma argila expandida, nas gradua??es 9,5 mm/0500 e 19 mm/1506. A argila de gradua??o maior era revestida com uma camada vitrificada, o que propiciou menor absor??o de ?gua pelo concreto. Os resultados mostraram que a utiliza??o da argila expandida como agregado leve ? uma solu??o tecnicamente vi?vel na produ??o de concreto leve para Constru??o Civil.

Technological advances in horizontal drilling and hydraulic fracturing have paved the way for the exploration and production of shale gas and shale oil, the fastest growing energy sector globally. The imaging and quantification of the geometry, sizes, network and distribution of extremely fine-grain minerals, organic matter and pores are a significant component for the macroscopic and microscopic characterisation of shale reservoirs but is also highly challenging. X-ray computed tomography (XCT) combined with 3D Electron Microscopy (EM) are used to address this challenge and give us information in 3D from multiple length scales over 3 orders of magnitudes: mesoscale (R1), microscale (R2), submicron-scale (R3), low-resolution nanoscale (R4) and high-resolution nanoscale (R5) with spatial resolutions of ~10micro metre, ~1micro metre, ~130 nm, ~50nm and ~5nm, respectively. The multi-scale imaging and quantification method was initially applied here to the Carboniferous Bowland Shale, the largest potential shale gas play in the UK. The appropriate length scales (both field of view and voxel size) of specified phases such as pores, organic matter, clay minerals and non-clay minerals were analysed. The low connectivity of pores and high connectivity of organic matter suggests that the 20 nm and larger pores imaged did not form connected flow paths, demonstrating that porous gas flow through this sample cannot be the main transport mechanism and diffusive transport through the organic matter and clay minerals must also be considered. Then, the variation of organic matter and pore distribution along a TOC gradient were analysis on Lublin gas-mature shale samples in Poland and Baltic oil-mature shale samples in Lithuania. The results show intergranular pores dominated in this series of samples, including organic interface pores and inter-mineral pores, which further confirm that organic matter is not the primary influencing factor for porosity, but the clay minerals. Finally, a novel multi-stage workflow of pore system is proposed relying on both image quantification and numerical modelling of geological features with studies in Jurassic Haynesville shale in the US. Three stages are divided according to pore variation, mineral variation and microfacies variation across four distinct length scales (R1-R4/R5), and permeability was simulated based on the upscaled pore system. The final computed porosity and permeability shows acceptable errors when compared with the helium porosity and press decay permeability. Beyond the lab measurements, the pore occurrence and size distribution were computed in the upscaling process. The combining of XCT and 3D-EM provides a powerful tool for the multi-scale imaging and quantification of microstructural information in shales, allowing the visualization of pores, organic matter and inorganic mineral phases over a range of scales over three orders of magnitude (~ 10 micro metre to ~ 5 nm), and the volume fraction of each phases shows a reasonable correlation to traditional physical and chemistry quantification data. The further studies, such as the variation of organic matter and pores, upscaling of porosity and permeability presented in this study, has verified the feasibility of the proposed multi-scale method and promises a bit potential for reservoir prediction and other challenges in geological studies.

We characterize various types of σ-porosity via an infinite game in terms of winning strategies. We use a modification of the game to prove and reprove some new and older in- scribing theorems for σ-ideals of σ-porous type in locally compact metric spaces. We show that there exists a closed set which is σ-(1 − ε)-symmetrically porous for every 0 < ε < 1 but which is not σ-1-symmetrically porous. Next, we prove that the realizable by an action unitary representations of a finite abelian group Γ on an infinite-dimensional complex Hilbert space H form a comeager set in Rep(Γ, H). 1

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-08-29T23:45:59Z No. of bitstreams: 1 ANDREZZA SOUSA SILVA – DISSERTAÇÃO (PPGEPM) 2018.pdf: 5233631 bytes, checksum: 12ad47a8373c6479a15d2cbfeba06e8d (MD5) / Made available in DSpace on 2018-08-29T23:45:59Z (GMT). No. of bitstreams: 1 ANDREZZA SOUSA SILVA – DISSERTAÇÃO (PPGEPM) 2018.pdf: 5233631 bytes, checksum: 12ad47a8373c6479a15d2cbfeba06e8d (MD5) Previous issue date: 2018-03-19 / A Bacia Rio do Peixe (BRP) apresenta diversas estruturas rúpteis, dentre elas as bandas de deformação, que podem controlar as propriedades petrofísicas e aspectos texturais das rochas. Portanto, o objetivo deste trabalho é identificar os efeitos causados pelos diferentes tipos de bandas de deformação cataclásticas, em função da cinemática, sobre os aspectos texturais, distribuição de tamanho de grãos e poros, bem como porosidade em arenitos conglomeráticos. As propriedades dos grãos e dos poros foram extraídas através da análise de imagens em seções delgadas no Avizo Fire 8.1. No total foram analisadas 23 amostras, 19 com bandas de deformação (CB) com orientação definida (NW, NE, NS e EW), 2 amostras deformadas, porém sem bandas (SB) e 2 amostras da rocha hospedeira (ND). As rochas deformadas (CB e SB), apresentam redução no tamanho de grãos e pequeno acréscimo nos valores dos aspectos texturais em comparação a rocha não deformada (ND). Em relação à porosidade foi encontrada redução de 66% nas amostras CB e acréscimo de 13% nas SB. Ambos agrupamentos possuem maior conexão de grãos, permitindo o surgimento da macroporosidade, que não havia sido detectada nas amostras ND. Dentre as amostras com banda de deformação e cinemática definida, a rochas associadas ao sistema transcorrente dextral, de direção NW, possuem maior redução de diâmetro de grão, e menor redução de porosidade, cerca de 29%. As amostras com bandas de deformação NE e NS, formadas por cinemática transtensiva, são as amostras nas quais houve a menor quebra dos grãos, entretanto caracterizam-se pela presença de porosidade por fraturamento de grãos, gerando altos picos de macroporosidade. As amostras oriundas do sistema distensivo de direção EW possuem segunda maior redução de grãos, maior redução de porosidade e ausência de macroporosidade. Os aspectos texturais (circularidade, convexidade e razão de aspecto) das amostras com banda (NW, NE, NS e EW) é dependente da intensidade de cisalhamento provocado por diferentes sistemas deformacionais, quanto mais intenso mais cominuído será o grão, e consequentemente mais convexo, circular e menos alongado. Logo, é possível observar que a cinemática e a presença de bandas de deformação exercem controle sobre os aspectos texturais e petrofísicos dos arenitos conglomeráticos da Formação Antenor Navarro. E esse controle é definido pela compactação da rocha, rearranjo dos grãos, intensidade da catáclase, presença de fraturamento de grãos e cinemática atuante. / The Rio do Peixe Basin (RPB) presents several rump structures, among them the deformation bands, which can control the petrophysical properties and textured aspects of the rocks. Therefore, the objective of this work is to identify the effects caused by the different types of cataclastic deformation bands, as a function of kinematics, on the textural aspects, grain and pore size distribution, as well as porosity in conglomeratic sandstones. The grain and pore properties were extracted by thin section image analysis in Avizo Fire 8.1. In total, 23 specimens were analyzed, 19 with deformation bands (CB) with defined orientation (NW, NE, NS and EW), 2 deformed samples, but without bands (SB) and 2 samples of host rock (ND). The deformed rocks (CB and SB), present a reduction in grain size and small increase in the values of the textured aspects in comparison to the non-deformed rock (ND). In relation to the porosity, a reduction of 66% was found in the CB samples and a 13% increase in the SB. Both clusters have a larger grain connection, allowing the appearance of macroporosity, which had not been detected in the ND samples. Among the samples with deformation band and defined kinematics, the rocks associated to the dextral transcurrent system, NW direction, have a larger reduction of grain diameter, and a smaller reduction of porosity, about 29%. The samples with NE and NS deformation bands, formed by transtensive kinematics, are the samples with the lowest grain breakage. However, they are characterized by the presence of porosity by grain fracturing, generating high peaks of macroporosity. The samples from the EW steering distance system have the second largest grain reduction, greater reduction of porosity and absence of macroporosity. The textural aspects (roundness, convexity and aspect ratio) of the banded samples (NW, NE, NS and EW) are dependent on the shear strength caused by different deformation systems, the more intense the grain is, the more convex, circular and less elongated. Therefore, it is possible to observe that kinematics and the presence of deformation bands exert control over the texture and petrophysical aspects of the conglomeratic sandstones of the Antenor Navarro Formation. And this control is defined by the rock compaction, rearrangement of the grains, the intensity of the catachase, presence of grain fracture and active kinematics.

Concrete, the major construction material used in the civil industry worldwide, displays remarkable performance and economic benefits. Yet, it also presents a huge environmental impact producing about 7% of the global carbon dioxide (CO2). Given the rise of global warming concerns, studies have been focusing on alternatives to reduce the amount of Portland cement (PC), which is the least sustainable ingredient of the mixture, for example by adopting particle packing model (PPM) techniques. Although a promising alternative, there is currently a lack of studies regarding the efficiently use of PPMs to reduce PC without compromising the fresh and hardened properties of the material. This work appraises the influence of PPMs and advanced mix-design techniques on the fresh (rheological behaviour) and hardened (compressive strength, modulus of elasticity, porosity, and permeability) state behaviours of systems with reduced amount of PC, the so-called low cement content (LCC) concrete. Results show that is possible to produce eco-efficient concrete maintaining and/or enhancing fresh and hardened properties of the material. Nevertheless, further durability and long-term behaviour must be performed on LCC systems.

A abordagem do comportamento hidráulico associado ao comportamento mecânico de um material é de extrema importância. A técnica de tratamento de solos com cal vem sendo empregada com sucesso na engenharia geotécnica, melhorando as características do solo, que por ser um material complexo e variável nem sempre satisfaz as necessidades requeridas para um projeto. Nesse sentido, este estudo tem por objetivo quantificar a influência da quantidade de cal e da porosidade sobre o comportamento hidráulico e mecânico de um solo residual tratado com cal, verificando a adequação do uso da relação vazios/cal na estimativa da condutividade hidráulica, da resistência à compressão simples (qu) e da resistência à tração (qt). Para isso, foram realizados ensaios de condutividade hidráulica e de resistência para corpos de prova com 5%, 7% e 9% de cal, com peso específico aparente seco de 16,0 kN/m³, 17,2 kN/m³ e 18,5 kN/m³, curados por 28 dias. Foi observado que a porosidade da mistura é um parâmetro de influência sobre a condutividade hidráulica medida. Ambas as resistências, à compressão simples e à tração por compressão diametral, aumentaram potencialmente com a redução da porosidade. Verificou-se uma única relação qt/qu igual a 0,13, sendo independente da relação vazios/cal. A metodologia proposta por Consoli (2014), mostrou-se adequada para a determinação dos parâmetros de resistência (intercepto coesivo e ângulo de atrito) para uma relação [n/(Liv)0,12=35. A relação vazios/cal, definida pela razão entre a porosidade da mistura compactada e o teor volumétrico de cal, ajustado por uma potência, demonstrou ser um parâmetro eficaz na estimativa do comportamento hidráulico e mecânico do solo-cal estudado. / The approach of the hydraulic behavior associated with the mechanical behavior of a material is of utmost importance. The technique of treating soil with lime has been used successfully in geotechnical engineering, improving the characteristics of the soil, which is a highly variable and complex material, and does not always meet the required needs. In that sense, this study has for objective to quantify the influence of amounts of lime and of the porosity on the hydraulic and mechanical behavior a sandy silt soil stabilized with lime, checking the suitability of the use de voids/ lime ratio in estimating of the hydraulic conductivity, unconfined compression strength (qu) and tensile strength (qt). For that, number of hydraulic conductivity tests and strength tests were carried out for soil-hydrated lime blends, with lime contents of 5%, 7% e 9%, dry unit weight of 16,0 kN/m³, 17,2 kN/m³ and 18,5 kN/m³, 28 days as curing time. It was observed that the porosity of the mixture is a parameter influence on the hydraulic conductivity measured. The results show the unconfined compressive and the splitting tensile strength increasing potentially with the reduction of its porosity. It was found a single qt/qu relationship equal to 0,13, being independent of the porosity/lime ratio. The methodology suggested by Consoli (2014), was adequate for determining of Mohr-Coulomb failure parameters (effective cohesion intercept effective angle of shearing resistance) for a ratio [n/(Liv)0,12=35. The voids/lime ratio, defined as the ratio between the porosity of the compacted mixture and volumetric lime content, adjusted by a power, demonstrated to be the most appropriate parameter to assess the hydraulic and mechanical behavior of the soil-lime mixture studied.

A técnica de estabilização de solos através da incorporação de agentes cimentantes é uma opção eficaz e amplamente utilizada em obras de engenharia geotécnica. Portanto, são relevantes os estudos que contemplam aspectos ainda não bem compreendidos relativos aos efeitos causados pela adição de agentes cimentantes na porosidade dos materiais obtidos e, por consequência, nas propriedades de desempenho destas misturas. Neste sentido, o presente trabalho pretende contribuir no que tange ao conhecimento da estrutura de poros de solos compactados tratados com cal e cimento e sua relação com o comportamento hidráulico destes materiais. Os solos utilizados têm granulometria arenosa e areno-siltosa. As variáveis de controle envolvidas nas análises são os teores dos agentes de cimentação empregados (cal e cimento), densidades de compactação e tempos de cura (para amostras com cal). Para a caracterização dos sistemas de poros empregou-se porosimetria por intrusão de Mercúrio e, de forma complementar, na quantificação das porosidades globais, microtomografia computadorizada de raios x. Um permeâmetro de parede flexível foi utilizado para as determinações das condutividades hidráulicas das amostras estudadas através de ensaios de carga constante. Para as amostras de matriz arenosa pura, os volumes de intrusão indicaram maior refinamento da rede porosa, sob efeito da cimentação, para as condições mais densas de moldagem. Para as amostras de matriz areno-siltosa, ao se variarem as condições de cimentação, e fixando-se o peso específico aparente seco, os volumes intrudidos indicaram o refinamento dos poros quando da adição de cal ou cimento em comparação à condição não cimentada. Com respeito à análise da influência do tempo de cura para as amostras moldadas com cal, os resultados sugeriram que a adição de cal (aos 7 dias de cura) não causou variação da porosidade, comparada à condição sem cimentação, mas aos 28 dias foi possível perceber o aumento da porosidade global e, com o passar do tempo (180 dias) verificou-se a redução da porosidade. O refinamento dos poros se tornou cada vez mais pronunciado conforme a evolução do tempo. Para a matriz arenosa, foi identificado que a adição de cimento e a variação da porosidade de moldagem não implicaram em mudanças mensuráveis no valor da condutividade hidráulica, quando comparadas às condições com e sem cimento. Para as amostras da matriz areno-siltosa, sob diferentes condições analisadas (adição de cal aos diferentes tempos investigados e adição de cimento), foi evidenciado que o peso específico aparente seco de moldagem causou influência significativa sobre a condutividade hidráulica. Foram obtidos bons ajustes para as correlações condutividade hidráulica versus relação porosidade/teor volumétrico do agente cimentante ao se aplicar a potência de 0,032 sobre o parâmetro teor volumétrico do agente cimentante. As curvas obtidas apresentaram relações distintas e sinalizaram aspectos do comportamento do material: aumento da condutividade hidráulica para 28 dias de cura da cal, em relação a 7 dias; para 180 dias e amostras nas condições menos densas, não ocorreu modificação em relação à idade de 28 dias, mas na condição mais densa o parâmetro investigado tornou-se sensível às modificações promovidas por efeitos do tempo de cura; ainda, para as amostras moldadas com cimento, ocorreu redução mais pronunciada da condutividade hidráulica relacionada às condições mais densas de moldagem. / The soil stabilization technique which incorporates cementing agents is an effective alternative and widely used in geotechnical engineering works. Therefore, research on the aspects not well understood related to the effects caused by the addition of cementing agents on the porosity of the obtained materials and, consequently, on the performance properties of cemented blends, are relevant. In this sense, this study aims to contribute improving the knowledge on the pore structure of compacted soils treated with lime and cement, as well as to the relationship between pore structure and the hydraulic behavior of these materials. The used soils have a sandy and sandy-silty grain size distribution. The studied variables involved in the analysis are: the cement and lime contents; compaction density; and curing time (for samples with lime). To characterize the pore systems it was employed the Mercury intrusion porosimetry test and, additionally, in order to quantify the global porosities, it was used x-ray computed microtomography tests. A flexible wall permeameter was used to determinate the hydraulic conductivity of the samples through constant head tests. For sandy samples, the intrusion volumes indicated a more significant reduction of the porous media, under the effect of the cementation, when compacted in denser conditions. For the sandy-silt samples, it was observed that by maintaining the specific dry unit weight constant and by varying the cementation conditions, the intruded volumes indicated a reduction of the pores after the addition of lime or cement compared to the uncemented samples. With regards to the influence of the curing time for samples treated with lime, the results suggested that the addition of lime after 7 days of curing did not cause variation in porosity, compared to condition without cementing additions; however, after 28 days of curing it was observed a slight increase on the overall porosity and, after 180 days of curing, it was observed a reduction of the porosity. The reduction of the pores became more significant with the curing time. Related to the sandy soil, the results indicated that addition of cement to the soil and variations on the molding porosity did not result in measurable changes in the hydraulic conductivity, when compared the conditions with and without cement. For the sandy-silt samples, which were analyzed under different conditions (addition of lime and different curing times, and addition of cement), it was shown that the specific dry unit weight caused significant influence on the hydraulic conductivity. It was observed a satisfactory correlation between hydraulic conductivity and porosity/cementing agent ratio when the volumetric cementing agent content is to the power of 0,032. The obtained curves showed distinct relationships and indicated the following aspects of the material behaviour: the increasing of the hydraulic conductivity after 28 days of curing of the sample with lime, compared to 7 days of curing; after 180 days of curing and under low compaction conditions, it was observed no changes when compared to the samples tested after 28 days of curing; however, in the densest condition the investigated parameter became dependent on the curing time; moreover, for the samples molded with cement, it was observed a more significant reduction of the hydraulic conductivity related to denser molded conditions.