Copies of author's previously published articles inserted. / Bibliography: leaves 173-196. / xviii, 197 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The objective of this thesis is to investigate the factors affecting swelling and dispersion of alkaline sodic soils containing lime and the ways to manage these soils to improve their physical condition. Studies on pure clay systems are included to understand the fundamental process involved in swelling and dispersion of pure and soil clays. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science

As argamassas para assentamento e revestimento de alvenarias, empregadas nas regiões metropolitanas de vários estados do Brasil, são tradicionalmente constituídas de cimento e areia com adições de argilominerais, denominados de saibro ou arenoso. Essas adições fornecem à argamassa trabalhabilidade, retenção de água e plasticidade semelhantes às da argamassa mista (cimento e cal). Apesar 40 uso, pouco se conhece quanto às características do saibro para seu emprego em argamassas. A escolha do saibro para uso em argamassa é realizada de forma empírica, ocasionando muitas vezes, patologias nos revestimentos. O objetivo deste trabalho foi analisar amostras de saibro para utilização em argamassas de cimento e saibro (ACS). Foram coletadas 62 amostras de saibros em 24 jazidas, em suas maiorias exploradas comercialmente na Região Metropolitana do Recife (RMR). Foram realizados 21 ensaios de caracterização química na totalidade das amostras de saibros. Foi proposto um índice de qualidade de saibro para argamassa (IQSA) e selecionadas 9 amostras de saibro para utilização em argamassas. Foram realizadas análises em argamassas frescas e ensaios mecânicos em argamassas endurecidas com dois traços. Os resultados foram analisados estatisticamente pela análise de componentes principais (PCA). Os resultados da caracterização química mostraram que os Saibros da RMR de melhor qualidade para argamassas de alvenaria foram coletados na área Norte. As principais características químicas dos Saibros que influenciaram positivamente a qualidade das ACS foram: pH, Capacidade de Troca de Cátions (CTC < 27 cmolc kg-l), Superfície específica (SE < 10 m2g-I), Percentagem de óxido de silício e Percentagem de água no extrato de saturação. Os indicadores que envolvem características químicas e físicas são fundamentais para qualificar o desempenho de argamassas.

Made available in DSpace on 2017-06-01T17:57:24Z (GMT). No. of bitstreams: 1 pre-textuais.pdf: 5777516 bytes, checksum: 35995ebd7e6e4cb8d83e00e62aa66616 (MD5) Previous issue date: 2008-12-18 / The mortars used in many parts of Brazil to set blocks or to cover masonry are normally prepared with cement and sand with clay minerais additions, called "saibro" or "arenoso" (a clayey sand). These additions provide workability, water retention and plasticity to the mortars, similarly as in the mixed mortars (cement, sand and lime). The properties of "saibro" are poorly known, in spite of its large use. Therefore, the choice of "saibro" to use in mortars has been empirical, and the mortars quality is not guaranteed, what may cause some pathology in the masonry covers. The objective of this work was to analyze "saibro" samples to be used in cement and "saibro"mortars (CSM). Sixty two samples of "saibro" were collected from 24 ofthe most commercially explored fields in the Recife's Metropolitan Area. Chemical "saibro" characterization tests, with 21 determinations, were applied to ali samples. A quality index of "saibro" for mortars (QISM) was proposed and nine samples of "saibro" were selected to be used in mortars. Chemical analysis for fresh mortars and mechanical tests for the hardened ones were provided for two different compositions. The results were statistically analyzed by principal components analysis (PCA). The chemical characterization tests showed that the best "saibros" for masonry mortars were collected in the northern part of the studied region. The "saibro" maio chemical characteristics that influenced positively the quality of the CSM were: pH, Cations Exchange Capacity (CEC < 27 cmoic kg-1), Surface Area (SA < 102 m2g-1), Silicon Oxide Percentage and Water Percentage in the Saturation Extract. The physical and chemical indicators are fundamental to qualify the mortars performance. / As argamassas para assentamento e revestimento de alvenarias, empregadas nas regiões metropolitanas de vários estados do Brasil, são tradicionalmente constituídas de cimento e areia com adições de argilominerais, denominados de saibro ou arenoso. Essas adições fornecem à argamassa trabalhabilidade, retenção de água e plasticidade semelhantes às da argamassa mista (cimento e cal). Apesar 40 uso, pouco se conhece quanto às características do saibro para seu emprego em argamassas. A escolha do saibro para uso em argamassa é realizada de forma empírica, ocasionando muitas vezes, patologias nos revestimentos. O objetivo deste trabalho foi analisar amostras de saibro para utilização em argamassas de cimento e saibro (ACS). Foram coletadas 62 amostras de saibros em 24 jazidas, em suas maiorias exploradas comercialmente na Região Metropolitana do Recife (RMR). Foram realizados 21 ensaios de caracterização química na totalidade das amostras de saibros. Foi proposto um índice de qualidade de saibro para argamassa (IQSA) e selecionadas 9 amostras de saibro para utilização em argamassas. Foram realizadas análises em argamassas frescas e ensaios mecânicos em argamassas endurecidas com dois traços. Os resultados foram analisados estatisticamente pela análise de componentes principais (PCA). Os resultados da caracterização química mostraram que os Saibros da RMR de melhor qualidade para argamassas de alvenaria foram coletados na área Norte. As principais características químicas dos Saibros que influenciaram positivamente a qualidade das ACS foram: pH, Capacidade de Troca de Cátions (CTC < 27 cmolc kg-l), Superfície específica (SE < 10 m2g-I), Percentagem de óxido de silício e Percentagem de água no extrato de saturação. Os indicadores que envolvem características químicas e físicas são fundamentais para qualificar o desempenho de argamassas.

Foi realizado na Região Metropolitana do Recife nos municípios de Abreu e lima, Araçoiaba, Cabo de Santo Agostinho, Camaragibe, Igarassu, Ipojuca, Itamaracá, Itapissuma, Moreno, Olinda, Recife, Jaboatão dos Guararapes e São Lourenço da Mata a coleta de materiais que servem como Saibro, em jazidas já exploradas comercialmente, com o objetivo de avaliar a melhor característica desse Saibro e a aplicação em argamassas na construção civil, bem como o seu uso de modo não mais empírico. Para isso se fez jus os ensaios de caracterização física através da análise granulométrica com sedimentação de acordo com a ABNT-NBR 7181/1984, a consistência (limite de liquidez conforme ABNT-NBR 6459/1984 e limite de plasticidade conforme ABNT-NBR 7180/1984). A determinação da massa específica dos grãos do solo de acordo com a ABNT-NBR 6508/1984, limite de contração de acordo com a ABNT-NBR 7183/1982. Os resultados obtidos indicam que existe influência significativa na quantidade de argila e no grau de contração. / It was accomplished in the Metropolitan Area of Recife in the municipal districts of Abreu e Lima, Araçoiaba, Cabo de Santo Agostinho, Camaragibe, Igarassu, Ipojuca, Itamaracá, Itapissuma, Moreno, Olinda, Recife, Jaboatão dos Guararapes and São Lourenço da Mata the collection of materials that they serve as Clay-Shale, in lied explored already commercially, with the objective of evaluating the best characteristic of that Clay-Shale and the application in mortars in the building site, as well as his/her way use no more empiric. For that it was made right the rehearsals of physical characterization through the analysis granulométrica with sedimentation in agreement with ABNT-NBR 7181/1984, the consistence (liquidity limit according to ABNT-NBR 6459/1984 and plasticity limit according to ABNT-NBR 7180/1984). The determination of the specific mass of the grains of the soil in agreement with ABNT-NBR 6508/1984, contraction limit in agreement with ABNT-NBR 7183/1982. The obtained results indicate that significant influence exists in the amount of clay and in the contraction degree.

Découvert dans les années 1970 sur le site palafitte aujourd’hui immergé du Crêt de Châtillon (lac d’Annecy, Haute-Savoie, France), le four de Sévrier, daté de l’âge du Bronze, est considéré comme un des plus anciens fours de potier d’Europe occidentale. Il incarne l’arrivée d’une nouvelle technologie qui marquera la disparition progressive des modes de cuisson en fosse ou en meule en usage depuis l’invention de la poterie. En cette fin de l’âge du Bronze l’acmé de l’art céramique, représenté par les productions de poteries fines, pouvait donc être lié à l’utilisation d’un tel dispositif. Le caractère unique de cette construction en argile, de dimensions modestes et à parois étonnamment minces, réside dans sa conception modulaire et portable. La découverte publiée en 1975 (Bocquet et Couren 1975) recueille aussitôt un échoeuropéen et près de quarante ans après, elle reste pratiquement sans équivalent. L’utilisation de fours de potier à l’âge du Bronze, dans un contexte occidental, demeure pourtant une question ouverte et depuis les années 80, l’interprétation avancée pour le four de Sévrier alimente régulièrement ce débat. L’objectif de cette thèse de doctorat est de porter un nouveau regard sur cet objet de référence quelque peu voilé par sa célébrité et réexaminer les hypothèses fonctionnelles non encore étudiées. Après une présentation du contexte et de l’historique de la découverte, un premier volet aborde différents aspects de l’objet archéologique: sa morphologie, sa conception, sa restauration, son comportement lors d’expérimentations de cuissons de céramiques, ses traits singuliers qui le rapprochent ou le distinguent des fours de potiers plus tardifs ou des structures d’argile à parois fines diversement interprétées. Notre analyse du four de Sévrier comporte trois volets : a) l’inventaire du matériel découvert sur le Crêt de Châtillon et l’intégration éventuelle d’éléments non pris en compte dans la reconstruction, b) une analyse archéométrique (minéralogie des argiles) portant sur les tessons du four et sur des argiles des gisements situés à proximité du Crêt de Châtillon. Une analyse des changements de phases des argiles cuites en fonction de l’intensité de la température, c) l’évaluation de la température minimale et maximale subie par le four afin de confirmer ou exclure certaines utilisations. L’analyse fonctionnelle du four aborde, en premier lieu, l’hypothèse privilégiée, celle consacrée à la cuisson des poteries. Une méthode expérimentale comparative permet de préciser les avantages et inconvénients de différents procédés de cuisson de poteries noires et cherche à évaluer l’apport technologique supposé avoir été introduit par le four de Sévrier. D’autres alternatives sont abordées, en particulier la fonction culinaire. Cette interprétation est confortée par la découverte d’inédits indices d’usages observés lors de cette étude sur des matériels similaires de même époque et provenance. L’inventaire des structures comparables constitue un autre volet de cette recherche. Elle témoigne de l’usage courant des structures de cuisson en argile de faible épaisseur aux âges du Bronze et du Fer. Leur diffusion géographique s’étend des Balkans à l’Espagne et de la Grande Bretagne à la Grèce. Le recensement d’une famille large et multiforme de dispositifs portables en argile à vocation domestique nous permet de poser les bases d’une typologie et de proposer un scénario d’évolution et d’influences entre des régions parfois très éloignées. / This study focuses on a unique archaeological finding from the Crêt de Châtillon, a late Bronze Age lacustrine village situated on a now submerged island in Lake Annecy (Haute-Savoie, France). The Sévrier kiln is considered to be one of the oldest pottery kiln in Western Europe. Over the years it has become internationally known and still forms the basis of research projects and experiments relating to Bronze Age ceramic technology. It embodies the arrival of a new technology that would mark the gradual disappearance of the open fire or pit firing modes that had been used since the invention of pottery. As such, the acme of ceramic art which marks the end of the Bronze Age, may therefore be related to the use of such a device. The uniqueness of this clay building of modest proportions and surprisingly thin walls, lies in it modular and portable design. The discovery, published in 1975 (Bocquet and Couren 1975) soon received a valuable feedback in Europe and nearly forty years later remains virtually unparalleled. However, the use of pottery kilns in the Bronze Age in a Western context remains an open question. Since the 1980s, several arguments will gradually undermine this interpretation. The purpose of this study is to take a fresh look at this inescapable object, somewhat veiled by its celebrity and review functional hypotheses hitherto not studied. After describing the background and the history of the discovery, we discuss various aspects of the archaeological kiln: morphology, design, restoration, use, experimentations and singular features that approximate or distinguish this furnace from later pottery kilns or thin-walled clay structures wich have been variously interpreted. This analysis of the kiln of Sévrier has been threefolds: (a) an inventory of the findings from the Crêt de Châtillon and a discussion about the integration of many components excluded from the reconstruction ; (b) archaeometric analysis (clay mineralogy) of the kiln and the clay deposits located near the site and (c) identification of the changing phases in clays, subjected to high temperatures and determination of the temperature experienced by the furnace. The functional analysis, reviews different hypotheses : (a) pottery firing : a comparative experimental method that aims to highlight the benefits and disadvantages of different processes to produce black pottery. The purpose is to underscore the technological contribution assumed to have been introduced by the Sévrier kiln. (b) Other functional alternatives will be discussed, especially the culinary function. This interpretation is supported by the discovery of unprecedented indices discovered during this study. The inventory of comparable structures is another aspect of this research. The relatively widespread use of such thin-walled clay structures during the Bronze and Iron ages is highlighted. Their geographical distribution extends from the Balkans to Spain and from Great Britain to Greece. The census of a multiform family of domestic portable clay ovens allows us to propose a new typology and a scenario of diffusion between regions sometimes very remote, completes this new outlook and draw new perspectives for the research.

Made available in DSpace on 2017-06-01T17:57:24Z (GMT). No. of bitstreams: 1 dissertacao_wellington_amorim.pdf: 3048381 bytes, checksum: 333317e062126e6f626919d08764c6a7 (MD5) Previous issue date: 2008-12-01 / It was accomplished in the Metropolitan Area of Recife in the municipal districts of Abreu e Lima, Araçoiaba, Cabo de Santo Agostinho, Camaragibe, Igarassu, Ipojuca, Itamaracá, Itapissuma, Moreno, Olinda, Recife, Jaboatão dos Guararapes and São Lourenço da Mata the collection of materials that they serve as Clay-Shale, in lied explored already commercially, with the objective of evaluating the best characteristic of that Clay-Shale and the application in mortars in the building site, as well as his/her way use no more empiric. For that it was made right the rehearsals of physical characterization through the analysis granulométrica with sedimentation in agreement with ABNT-NBR 7181/1984, the consistence (liquidity limit according to ABNT-NBR 6459/1984 and plasticity limit according to ABNT-NBR 7180/1984). The determination of the specific mass of the grains of the soil in agreement with ABNT-NBR 6508/1984, contraction limit in agreement with ABNT-NBR 7183/1982. The obtained results indicate that significant influence exists in the amount of clay and in the contraction degree. / Foi realizado na Região Metropolitana do Recife nos municípios de Abreu e lima, Araçoiaba, Cabo de Santo Agostinho, Camaragibe, Igarassu, Ipojuca, Itamaracá, Itapissuma, Moreno, Olinda, Recife, Jaboatão dos Guararapes e São Lourenço da Mata a coleta de materiais que servem como Saibro, em jazidas já exploradas comercialmente, com o objetivo de avaliar a melhor característica desse Saibro e a aplicação em argamassas na construção civil, bem como o seu uso de modo não mais empírico. Para isso se fez jus os ensaios de caracterização física através da análise granulométrica com sedimentação de acordo com a ABNT-NBR 7181/1984, a consistência (limite de liquidez conforme ABNT-NBR 6459/1984 e limite de plasticidade conforme ABNT-NBR 7180/1984). A determinação da massa específica dos grãos do solo de acordo com a ABNT-NBR 6508/1984, limite de contração de acordo com a ABNT-NBR 7183/1982. Os resultados obtidos indicam que existe influência significativa na quantidade de argila e no grau de contração.

MESMEG / Department of Mining and Environmental Geology / Vhembe District has several clay deposits which are traditionally use for clay products such as burnt bricks without taking into account the chemical and mineralogical characteristics of clay being used. The ever-increasing market demand for these clay products cannot be met with the traditional method of clay utilization due to the paucity of scientific information on properties of the clay in the area. Consequently, there is a need to gain better understanding of the characteristics of the clay in Vhembe District and to establish the suitability of the variety of clay for different purposes. The current study was undertaken to better understand the compositional relationship between the clay deposits and surrounding rocks present in the study area. It further aimed at characterizing the clay deposits on the basis of chemical, mineralogy, physical, mechanical, thermal and micro structural properties with a view of evaluating the clays for possible industrial use. A total of thirty-nine clay and rock samples were collected from thirteen different locations across the Vhembe District. Thirteen representative samples from each location were obtained after thorough mixing until homogenization was attained and then quartered for subsequent analyses. The mineralogical and chemical characteristics of the clay and rock samples were determined using XRD and XRF respectively. Thin-sections of the rock samples were prepared and examined under petrographic microscope to better understand the mineral assemblages present in the rocks. The thermal and micro structural properties of the clays were determined using DTA-TGA and SEM analyses and the physical properties which include colour, cation exchange capacity (CEC) and soil pH were assessed. The particle distribution and Atterberg limits tests of the clay samples were also conducted in order to establish their mechanical properties. The petrographic results showed that the clay deposits exhibited an intense weathering and sedimentation processes which incorporated detrital minerals from the surrounding rock units. The rock units which include basalt, granodiorite, gneiss and quartzofeldspathic gneiss were found to be differentiated from subalkaline and/or tholeiitic magmatic composition. Although the value of SiO2 content in rock samples was higher when compared with clay samples, it indicated an ongoing desilicication and allitization processes. The high values of chemical index of alteration (CIA), low values of K/Cs (<6200), Ce* normalized value and higher values of LILE enrichment in the clay deposits indicated oxidizing environments during period of deposition. v The mineralogical composition of the studied clayey deposits showed that smectite (8.25 - 29.32%), kaolinite (14.91 - 59.26%) and chlorite (5.94 -16.54%) were present as clay minerals although associated with other non-clay minerals such quartz, plagioclase, talc and geothite. The chemical composition results revealed high silica and alumina content in most studied clay samples. Their fluxing oxides which include K2O, Na2O, CaO, and MgO, varied slightly from 0.06% to 1.78% in abundance while the Fe2O3 and TiO2 contents in most samples averages at 9.2% and 1.3% respectively. The plasticity index of the studied deposits ranged from 9.50 to 62.00% while liquid limit ranged from 31.34 to 73.62%. The microanalysis using SEM indicated that the microstructure framework of most studied clay exhibited a porous skeleton structure owing to numerous tiny voids. The composite results of SEM and CEC analyses suggested their possible application in water filter and chemical fertilizer industries since they provided passage for water and soil cations transmission. The particle size distribution demonstrated that the studied soils have clayey silt texture with wide range coverage of the well graded and sorted particle sizes. Compressibility and plasticity properties were found to be high in Mukondeni, Mashamba-1, Mashamba-2 and Mashamba-3 clay samples. The thermal behavior of Mukondeni, Mashamba-1, Mashamba-2 and Mashamba-3 samples showed relatively high shrinkage (>9%). The high shrinkage percentage suggests the preponderance of smectite minerals. Other samples which are rich in kaolinite and chlorite minerals exhibited low shrinkage (<2%). The drying trends of the studied clay suggest their suitability for fast drying processes like soft and hard refractoriness, sanitary wares and ceramics. Empirical assessment of most studied clay showed their suitability for pottery-making and manufacturing of roofing tiles and masonry bricks. / NRF

<p>Probing the subsurface for evidence related to the degradation of porous mediums and the evolution of damage mechanisms has been a long-standing challenge in geophysics. As such imaging and predicting fracture network development has remained a difficult area for subsurface science for decades despite the seminal and significant works put forward by many researchers. While this has provide great understanding about the behaviours and properties of natural porous media, there is still much that needs to be explored particularly in regard to the mineralogical composition and chemistry of clay-rich rocks. Despite the fact that argillaceous rocks which consist of different types of clays and varied mineral composition are ubiquitous in nature and are often the target of several technologies (e.g. geotechnical engineering, nuclear waste storage and disposal,hydrocarbon exploration and extraction, carbon capture and sequestration, etc.), many studies focus primarily on the bulk properties or the percentage of components in the matrix. For these reason and due to the problems that can be encountered with natural rocks that contain a swelling clay component whether randomly distirbuted or localized in consolidated globs in zones of the matrix, the influence of clay chemistry in relation to fracture development which is not well characterized, especially during desaturation is investigated with analogue rock samples which were systematically fabricated for this purpose.</p> <p><br></p> <p>The research performed in this dissertation investigated, the applicability of  the fabrication protocol for developing synthetic rocks with desirable rock like features and behavior, the impact and relationship between the rock properties, the microstructural composition, water loss, and the macroscopic behavior of the analogue rocks, focusing on the structure and chemistry of the constituent clay materials. Synthetic rocks were fashioned with the necessary geometries, properties, and material compositions. On the macroscopic scale the fracture and drying behavior of the synthetic rocks were examined with 3D X-ray microscopy and further evaluated through the utility of acoustic emission monitoring, water loss monitoring, and unconfined compressive testing. On the finer scale (nano-microscale), the chemical and mechanical properties, and behavior of select clays was explored by exploiting several methods of material characterization which also included cation exchange experiments coupled with inductively coupled plasma – optical emission spectrometry (ICP-OES). </p> <p><br></p> <p>For the finer scale, experiments verified that calcined kaolinite clay had a different mineral structure and negligible to non-existence shrinkage abilities. In contrast, the montmorillonite clays possessed higher and similar moisture contents but, owing to the different principal cations these clays interacted a bit differently in the highly akaline environment, experienced varying degrees of shrinkage, and had observedly minor structural dissimilarities. For the relatively larger scale, the emergence of damage, extent of the damage network, and the patterns of the crack network mainly depended on the microstructural composition of the analogue rocks, particularly it's clay chemistry and/ or distribution. The location of damage depended on the emplacement and percentage of swelling clay in the matrix, and numerical investigations with peridynamics revealed that the observed damage was a consequence of the action of the swelling and non-swelling components of the matrix. Furthermore, if the microstructure consisted of no clay or calcined kaolinite the AE activity was solely attributed to interfacial processes that occurred during fluid front movement. If the microstructure consisted of a particular montmorillonite, the cracks propagated in the direction of the drying front. Conversely, for montmorillonite clay predominated by a different principal cation, the crack network developed and propagated differently during water loss. Additionally, on the laboratory core scale, properties and behavior similar to natural rocks were confirmed and the rock strength, porosity, AE activity, and velocities were primarily affected by the microstructural composition of the analogue rocks. </p> <p><br></p> <p>An added challenge for investigating and monitoring evolving systems and processes, whether on the laboratory or field scale, is the problem of extracting useful information from the physical data that can be used to identify signatures of developing processes, and changes in the properties or the behavior of a system. Here, data driven machine learning modeling and clustering techniques were undertaken to build a mechanistic understanding of the AE activity generated during drying. The intent is for this work to add to the fundamental research aimed at developing methods that will robustly detect and extract signatures related to evolutionary processes or features in the AE signals, and group them according to some degree of similarity. Such research will support reliable interpretations of the physical data for predictions of the behavior of systems, development of engineering controls, and improvement of the understanding of intrinsic dynamics related to complex processes particularly those that occur in clay-rich systems.</p> <p><br></p> <p>Combined chemical and mechanical investigations have great potential for unraveling practical challenges in subsurface science, especially regarding damage processes in clay-rich rock systems, and identifying and interpreting the presence of discontinuities from geophysical data. The present findings are useful for establishing a link between the constituent clay and observed damage, and improving our understanding of the development of damage in clay-bearing systems. These results provide insight on the influence of swelling clay and the chemistry of such clays on the generation of cracks and crack networks in rock like materials which can be useful for the characterization of damage in both laboratory and the field. The work presented here can also be a basis for further experiments that aim to uncover methods and protocols that will help with the indirect characterization of evolutionary processes, damage mechanisms, and damage in clay rich porous media. Additionally support for the use of analogue rocks in experimental rock physics, architected with specific material compositions, pore structures, crack systems, or clay fractions, is provided here. </p>