Thesis (MSc)--Stellenbosch University, 2004 / ENGLISH ABSTRACT: The main aim of this study is to establish a standard procedure for all sedimentary particle size analysis methods specifically for clay minerals and mixtures thereof. Not only will it improve accuracy and reproducibility during clay size analysis, it will also secure comparability between different operators. As a start, all the apparatus-related parameters that can affect the accuracy and reproducibility were determined for the apparatus used, viz. the Sedigraph SOOOD. Thereafter, these parameters were kept constant, and the effects of potential material-related parameters were investigated one-by-one. First to be investigated were those parameters relating specifically to sample preparation. They were: grinding intensity, chemical dissolution of cementing materials, duration of prior soaking, salt content, centrifugal washing with polar organic liquids, deflocculant type and concentration, the effect of pH, ultrasonic time, and stirring during ultrasonic treatment. Then, the influence on accuracy and reproducibility of the physical and chemical parameters related to the suspension was determined. They were: the use of the viscosity and density of water to calibrate the apparatus in stead of those of the suspension liquid, hydrolysis of the deflocculant with suspension-ageing, and the effect of solid concentration on hindered settling. During this investigation a novel method was developed to enable faster and more accurate pycnometric density determinations. Next, the unique characteristics of clays, which can influence the results of sedimentary particle size analyses, were examined. Serious problems are encountered with the accuracy of the analyses of some clay types abundantly found in nature, viz. the smectites and mixed-layered clay minerals. Due to their swelling in water, and variations in the amounts of their crystal layers, they experience unpredictable changes in particle size. The latter is caused by the following external factors: clay type, humidity, type of exchange cation, electrolyte concentration, clay concentration, pH, deflocculant type and concentration, pressure history of the swell-clay suspension, and ageing of the suspension. The effect of each of them on the accuracy and reproducibility of the sedimentary particle size analysis of clays are investigated in detail. Another problem that influences the accuracy of the sedimentary methods is that owing to swelling, the densities of smectites and mixed-layered clays change by varying degrees when suspended in water. It is, however, impossible to pycnometrically determine the density of a swell-clay since it absorbs a part of the water used for its volume determination. To solve this problem, a novel method was devised to calculate swell-clay density. This method makes use of existing Monte Carlo simulations of the swelling mechanism of montmorillonite. During all sedimentary methods, an average clay density is normally used to calculate the particle size distribution of clay mixtures. However, if there is a large enough difference between the calculated average density and that of a component, then inaccurate results will be recorded. The magnitude of this effect was investigated for a few self-made clay mixtures, which consisted of different proportions of kaolinite, illite, and montmorillonite. Based on all the above results, a practical approach to, and a standard methodology for all the sedimentary methods of particle size analysis of clay minerals are presented. Additionally, a condensed summary is provided in table-form, which contains the magnitudes of the errors associated with each of the parameters that were examined. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie is om 'n standaard prosedure daar te stel vir alle sedimentêre metodes van partikelgrootte analise, spesifiek vir gebruik met kleiminerale en mengsels daarvan. So 'n standaard prosedure sal die akkuraatheid en herhaalbaarheid van klei-analises verbeter, en die vergelykbaarheid tussen verskillende operateurs verseker. Aanvanklik is slegs die parameters bepaal wat die akkuraatheid en herhaalbaarheid van die gekose apparaat (Sedigraph 5000D) kan beïnvloed. Daarna is al hierdie parameters konstant gehou, en is die potensiële effekte van die moontlike materiaal-verwante parameters een na die ander ondersoek. Eerstens is die invloed van monstervoorbereiding op akkuraatheid en herhaalbaarheid bepaal. Verskillende parameters nl. maal-intensiteit, chemiese oplossing van sementerende materiale, sentrifugale wassing met polêre organiese vloeistowwe, tipe ontvlokker en konsentrasie, die effek van pH, ultrasoniese tyd en die effek van roer tydens ultrasonikasie is ondersoek. Vervolgens is die invloed op die akkuraatheid en herhaalbaarheid van die fisiese en chemiese parameters verwant aan die suspensie bepaal. Hierdie parameters was nl. die gebruik van die viskositeit en digtheid van water in plaas van dié van die suspensievloeistof, hidrolise van die ontvlokker tydens suspensieveroudering, asook die effek van vastestof-konsentrasie op belemmerde uitsakking. Gedurende hierdie ondersoek is ook 'n nuwe metode ontwikkel wat vinniger, en meer akkurate piknometriese digtheidsbepalings moontlik maak. Die unieke eienskappe van kleie wat die resultate van sedimentêre metodes van partikelgrootte analises kan beïnvloed, is volgende ondersoek. Tydens die analises van party kleie wat baie volop in die natuur voorkom, nl. die smektiete en menglaag-kleie, word ernstige akkuraatheids-probleme ondervind. Hul swelling in water, tesame met variasies in hul aantal kristal-lagies, veroorsaak onvoorspelbare verandering van hul partikelgroottes. Laasgenoemde word deur die volgende eksterne faktore veroorsaak: klei tipe, humiditeit, tipe uitruil-katioon, elektrolietkonsentrasie, kleikonsentrasie, pH, ontvlokker-tipe en konsentrasie, drukgeskiedenis van 'n swelklei-suspensie, en veroudering van die suspensie. Die effek van elk op die akkuraatheid en herhaalbaarheid van die sedimentêre partikelgrootte analises van kleie word in detail bespreek. 'n Verdere probleem wat die akkuraatheid van sedimentêre metodes beïnvloed, is dat wanneer smektiete en menglaag-kleie in water gesuspendeer word, hulle digthede in verskillende mates weens swelling verander. Dit is egter onmoontlik om die digtheid van swelkleie in water piknometries te bepaal, omdat swelklei 'n gedeelte van die water absorbeer wat gebruik moet word om die kleivolume mee te bepaal. Om hierdie probleem op te los, is 'n nuwe metode ontwikkelom die digtheid van swelkleie mee te bereken. Die metode maak gebruik van reedsbestaande Monte Carlo simulasies van die swelling van montmorillonite. Tydens alle sedimentêre metodes word normaalweg van 'n gemiddelde kleidigtheid gebruik gemaak om die partikelgrootte-verspreiding van kleimengsels mee te bereken. Indien die berekende gemiddelde digtheid egter genoegsaam met dié van 'n kleikomponent verskil, sal onakkurate resultate verkry word. Hierdie effek is ondersoek vir 'n paar selfgemaakte kleimengsels wat uit verskillende hoeveelhede kaoliniet, illiet, en montmorilloniet bestaan het. Laastens word 'n praktiese benadering en 'n standaard metode vir alle sedimentêre metodes voorgestel, wat gebaseer is op al die bogenoemde resultate. 'n Verkorte opsomming, met die groottes van die foute geassosieer met elke parameter wat ondersoek is, word laastens in tabelvorm verskaf.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Duas argilas do tipo esmectitas, uma montmorilonita da regiÃo de Campina Grande (Pb) e uma estevensita de Marrocos foram utilizadas no processo de intercalaÃÃo e pilarizaÃÃo com soluÃÃes oligomÃricas de alumÃnio. AtravÃs dos resultados de espectrometria ICP-AES com plasma indutivamente acoplado foram determinadas as composiÃÃes quÃmicas que resultaram nas fÃrmulas empÃricas (Na0,43K0,22Ca0,09)(Al1,48,Mg0,18,Fe0,34)2Si4O10(OH)2 e (Li0,09Na0,04K0,03Ca0,05)(Al,Mg,Fe)2(Si,Fe,Al)4O10(OH)2. da montmorilonita e da estevensita respectivamente.Os valores das Ãreas especÃficas foram 29 m2.g-1 e 228 m2.g-1, antes da intercalaÃÃo e de 106 m2.g-1 e 219 m2.g-1, apÃs a pilarizaÃÃo, para a montmorilonita e estevensita, respectivamente. As argilas foram submetidas a lavagens a quente com hipoclorito para remoÃÃo da matÃria orgÃnica, e transformadas na forma homoiÃnica com NaCl, seguidas de intercalaÃÃes com complexo de alumÃnio e pilarizaÃÃo a 500ÂC. AtravÃs de anÃlises termogravimÃtricas e por difratometria de raios-X, foi avaliada a influÃncia da matÃria orgÃnica na intercalaÃÃo das argilas. Os resultados mostraram que as espÃcies mais estÃveis foram Ãquelas submetidas ao tratamento com hipoclorito. A estevensita apresentou atividade catalÃtica de cerca de 15% acima da capacidade da montmorilonita, cujo mÃximo ficou em 50 % a 315 ÂC, mas com percentual de isomerizaÃÃo na ordem de 82%, cerca de 13% superior a estevensita; A produÃÃo de isÃmeros do tipo Mono e Di foram semelhantes para as duas argilas, sendo de 84% e 16% respectivamente; Os isÃmeros predominantes para ambas Ãs argilas foram 3-metilheptano e 2-4-dimetilhexano; Apesar das atividades catalÃticas das argilas pilarizadas nÃo terem atingindo os mesmos nÃveis que para as zeÃlitas, como a ZSM-22, os percentuais relativos de isomerizaÃÃo superam os valores reportados para essa zeÃlita, na temperatura onde as atividades dessas argilas sÃo mÃximas. / Two clays of the smectites type, a montmorillonite from the region of Campina Grande (Pb) and the stevensite of Marrocos were used in the process of intercalation and pillarization. Through the results of spectrophotometry of atomic absorption ICP-AES the chemical composition of the montmorillonite was determined as(Na0,43K0,22Ca0,09)(Al1,48,Mg0,18,Fe0,34)2Si4O10(OH)2. By the same process, the composition of the stevensite was determined as (Li0.09Na0.04K0.03Ca0,05)(Al,Mg,Fe)2(Si,Fe,Al)4O10(OH)2. The values of the specific areas were 29 m2.g-1 and 228 m2.g-1, before the intercalation and 106 m2.g-1 and 219 m2.g-1, after the pillarization, for the montmorillonite and stevensite, respectively. The clays were submitted to a treatment for removal of the organic matter and then transformed in the homoionic type with NaCl, and inserted with aluminium complex and pillarization at 500 oC. Through thermogravimetric analysis and X-Ray diffractometry, it was evaluated the influence of the organic matter in the intercalation of the clays. The results showed that the more stable samples were those submitted to treatment with hypochlorate. The stevensite presented catalytic activity of about 15% above the capacity of the montmorillonite, whose maximum was 50% at 315 oC. Its percentage of isomerization however, in the order of 82%, was about 13% more than for stevensite. The production of isomers of the Mono and Di type were similar for the two clays, being of 84% and 16% respectively. The predominant isomers for both clays were 3-methylheptane and 2-4-dimethylhexane. Despite the catalytic activities of the pillared clays having not reached the same levels for zeolites as ZSM-22, the isomerization relative percentages exceeded the figures reported for this zeolite, at the temperature where the activities of these clays are maximum.

Samples from nearly 800 Bronze Age pottery sherds from Euboea, Eastern Boeotia and Eastern Thessaly were analysed together with 9 raw clays from the same areas. The-analysis was carried out in an attempt to identify areas of pottery manufacture, to discover the origin of specific groups of pottery, to relate pottery to, raw clays and to see how far pottery compositions can be associated with, and predicted by, geology. The work was done on the same lines as earlier studies at the Oxford Laboratory and at the British School at Athens. The main analytical technique used was therefore optical emission spectroscopy. Some 25% of the total number of sherds were also analysed by atomic absorption spectrophotometry so that the results obtained by the two techniques could be compared. The interpretation of the results was facilitated by the use of, computer program packages for cluster and discriminant analysis. Both optical emission and atomic absorption analysis resulted in broadly similar groupings although the absolute concentrations were not directly comparable. The groupings obtained after atomic absorption analysis had the narrower concentration ranges. Nine elements were measured by both techniques but in atomic absorption potassium was added and proved; useful as an additional discriminant. Six composition groups were distinguished from the data. One of them was identified as Euboean, 2 as Boeotian and 3 as coming from different regions of Thessaly. The greatest movement of pottery within these areas was from Euboea to Thessaly. No composition group which originated from outside these regions was identified. Six of the 9 raw clays were associated with the prevailing composition group in the area from which they came. It was not possible to predict trends in pottery composition by examination of the local geology.

Made available in DSpace on 2017-06-01T17:57:35Z (GMT). No. of bitstreams: 1 felipe_melo_assis_rocha.pdf: 3429675 bytes, checksum: e5e8bc00c874077cf3c774174e26c3be (MD5) Previous issue date: 2016-03-02 / The origin of Recife´s plain is riverine and marine. Deposits of organic soft clay are spread in more than 50% of its area, which creates a favorable scenery for a occurrence of differential repression in several constructions foundations localized over these deposits. The present work treats of a geotechnical investigation of the a soft organic clay of the Chão de Estrelas s neighborhood. In this location many not deformed samples of this material were taken in the Beberibe riverside margin s that resulted in parameters of compressibility used as reference in the accomplishment of a road project for the neighborhood. This research, however, used the same soft organic clay sample´s of the Chão de Estrelas s neighborhood to accomplish a complementation of that first study. Besides, a vast collection of literature references on the compressibility of organic soft clay gave support to this study. The general objective this thesis is the analysis of the compressibility of a organic soft clay through of the vertical or radial drainage oedometer test; and, specifically, to study the influence of the preview drying these materials in the obtaining of the natural humidity these samples; to analyze the quality of this organic soft samples clays and to propose the correction of the field compressibility graph line´s; to make a comparison between the fists studies result´s or compressibility parameter s already classified and the news complements result´s by this work, and, in general, with results found in the plain of Recife city; to find accurate value to the pre-compression stress; and, to analyze the results of the compressibility parameters of the a unstructured sample with the results of the a structured sample in the same condition e depth. To achieve those goals, the research used five samples taken from two islands, this term refers to a region studied, called Island 1 e Island 2, respectively, referring of the borehole 203A e 208A. Of the Island 1 were taken in the three depths; while on the second Island were taken in the two depths; being executed two drainage rehearsals by each depth, five vertical drainage rehearsals and five radial drainage rehearsals. It were still accomplished for another vertical drainage rehearsals with a unstructured organic soft clay sample, totalizing 11 rehearsals. In all those rehearsals were used small adjustment or increments of the stress, always using less stress that the before stress, (Δσ/ , only in the area that precedes the virgin compression, way to define the best pre-compression stress value. The results of the compressibility parameters found in this work are in accordance with the literature values. The forms of the compressibility curves and the compression parameters values by the vertical and radial drainage rehearsals are shown similar. The plasticity index suffer influence of the previous drying of the material. The value of the pre-compression stress came closer in comparison with the results of the first study that based the road project for the Chão de Estrelas s neighborhood. This work demonstrated by the reconstruction of the curve of compressibility of the field that good quality organic soft clay samples´s suffer some percentual of the unstructured situation. / A planície do Recife apresenta origem flúvio-marinha, depósitos de argilas moles que se espalham em mais de 50% de sua área, tornando-se um cenário propício para a ocorrência de recalques diferenciais em bases e fundações de construções diversas assentadas sobre esses depósitos. A presente dissertação trata de uma investigação geotécnica em uma argila orgânica mole no bairro de Chão de Estrelas na cidade do Recife. Nesse local foram retiradas amostras indeformadas das margens do rio Beberibe que resultaram em parâmetros de compressibilidade utilizados como referência na realização de um projeto viário para o bairro. Este trabalho utiliza dessas mesmas amostras para realizar uma complementação desse primeiro estudo. Ademais, um vasto acervo de referências bibliográficas sobre a compressibilidade de solos moles deu suporte. O objetivo geral é a análise da compressibilidade de uma argila orgânica mole através dos ensaios de adensamento com drenagem vertical e radial; e, especificamente, estudar a influência da secagem prévia na obtenção da umidade das amostras; analisar a qualidade das amostras estudadas e propor a correção da curva de compressibilidade de campo; comparar seus resultados ou parâmetros de compressibilidade aos resultados já catalogados para o mesmo local da pesquisa e, de um modo geral, para a planície do Recife; obter valores mais precisos para a tensão de pré-adensamento; e, analisar parâmetros de compressibilidade de uma amostra completamente amolgada em laboratório com outra amostra indeformada de boa qualidade de mesma referência e profundidade. Para tanto, a pesquisa se utilizou de cinco amostras retiradas de duas Ilhas, termo esse que se refere a uma região estudada, ou seja, aos furos de sondagem 203A e 208A, respectivamente, Ilha 1 e Ilha 2. Da primeira foram retiradas amostras em três profundidades; enquanto a segunda ilha proporcionou amostras em duas profundidades; sendo executados dois ensaios de adensamento por profundidade, cinco por drenagem vertical e cinco por drenagem radial. Foi realizado também um outro ensaio de adensamento com drenagem vertical em amostra completamente amolgada em laboratório, totalizando assim 11 ensaios de adensamento. Em todos esses ensaios realizados foram utilizados incrementos de tensão menores que a tensão anterior, (Δσ/ , apenas na região que antecede a compressão virgem, de maneira a melhor definir a tensão de pré-adensamento. Os resultados dos parâmetros de compressibilidade encontrados na pesquisa estão em conformidade com a literatura. As formas das curvas de compressibilidade e parâmetros apresentados pelos ensaios de adensamento vertical e radial se mostraram semelhantes. O índice de plasticidade sofreu influência da secagem prévia do material. Os valores das tensões de pré-adensamento se apresentaram mais próximos em comparação aos primeiros estudos que embasaram o projeto viário no bairro de Chão de Estrelas no Recife. Foi demonstrado também que, pela reconstrução da curva de compressibilidade do campo, as amostras, mesmo as de boa qualidade, sofrem um percentual de amolgamento.

This study of ATR-IR involved taking spectra of various silicate minerals in powder samples, finding similarities and differences in nature, and locating various bands and intensities of absorption bands for identification and classification purposes. This study is limited to 4000-300 cm-1 with major emphasis on absorptions in the 2000-300 cm-1 region.

Samples from nearly 800 Bronze Age pottery sherds from Euboea, Eastern Boeotia and Eastern Thessaly were analysed together with 9 raw clays from the same areas. The-analysis was carried out in an attempt to identify areas of pottery manufacture, to discover the origin of specific groups of pottery, to relate pottery to, raw clays and to see how far pottery compositions can be associated with, and predicted by, geology. The work was done on the same lines as earlier studies at the Oxford Laboratory and at the British School at Athens. The main analytical technique used was therefore optical emission spectroscopy. Some 25% of the total number of sherds were also analysed by atomic absorption spectrophotometry so that the results obtained by the two techniques could be compared. The interpretation of the results was facilitated by the use of, computer program packages for cluster and discriminant analysis. Both optical emission and atomic absorption analysis resulted in broadly similar groupings although the absolute concentrations were not directly comparable. The groupings obtained after atomic absorption analysis had the narrower concentration ranges. Nine elements were measured by both techniques but in atomic absorption potassium was added and proved; useful as an additional discriminant. Six composition groups were distinguished from the data. One of them was identified as Euboean, 2 as Boeotian and 3 as coming from different regions of Thessaly. The greatest movement of pottery within these areas was from Euboea to Thessaly. No composition group which originated from outside these regions was identified. Six of the 9 raw clays were associated with the prevailing composition group in the area from which they came. It was not possible to predict trends in pottery composition by examination of the local geology.

The purpose of this work is to find a method of determining the average particle size in samples of clays and ceramical materials, and to attempt to classify their physical properties according to the size of the particles. Such data should be useful to compare the properties of clays, to match different samples for uniformity, and to better control processes where clays are used, as for instance in manufacture of paper, rubber, and burned wear. / M.S.

A basis for developing a general approach to solve geotechnical engineering problems through dynamic finite element analysis of nonlinear porous media is presented. A new series of constitutive models named here as δ* series are developed under the general hierarchical single surface (HISS) modeling approach, to include the behavior of, saturated normally consolidated and overconsolidated clay, under drained or undrained, static and cyclic loading conditions. Algorithms for determination of material parameters for these models from laboratory models are also developed. Constitutive parameters for Sabine Clay are obtained using triaxial test results from undisturbed samples and the model is verified by back predicting the laboratory behavior of this clay. Sensitivity analyses for all the material parameters have been also carried out. Efficient and reliable algorithms for calculating strain increments for given stress increments and vice versa are developed. All the models in the δ* series are implemented in the finite element program POROUS which is based on the theory of dynamics of nonlinear porous media. Here a modular approach is used to facilitate easy modification of all the functions associated with these models (yield function, potential function, hardening function and interpolation functions). Complete test procedure for field load tests on two pile segments (3 inch and 1.72 inch) are numerically simulated and compared with field measurements. Initial stresses before pile driving are estimated using results of s self boring pressuremeter test on the site. Strain distributions just after pile driving are evaluated using the strain path method. The effective stress distribution is obtained by integrating constitutive equations for given strain paths. Corresponding total stresses and pore pressure distributions are obtained using the computer program POROUS. Consolidation after pile driving and all the static and cyclic tests followed are also simulated using the program POROUS. The predicted normalized pore pressure dissipation curve matches the field behavior. This analysis provides good predictions of shear transfer from which the pile capacity can be evaluated. Even though the variation of pore pressure during a cycle is not matched exactly, the accumulation of pore pressures are predicted well. The demonstrated ability of dynamic finite element analysis of nonlinear porous media, to simulate slow consolidation and cyclic load tests provides a basis for developing a general approach for solving geotechnical engineering problems.

Copies of author's previously published articles inserted. Bibliography: leaves 173-196. 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.

Engineered organoclays are 2:1 phyllosilicate soils that have been synthesized with a controlled interlayer organic phase to exhibit enhanced strength, lower compressibility, and stronger retention of organic compounds. Engineered organoclays are highly sorptive, and have a variety of potential engineering applications as sorbents or amendments in engineered earthen barrier systems. Previous studies examined the impact of the organic coating on a soil's physical properties; however, the geochemical behaviors of organoclays, especially their interaction with organic compounds at the micro-scale, remained relatively unquantified. This study investigated the engineering behavior of montmorillonite modified with a variety of quaternary ammonium cations (QAC clays) with controlled structure and density of loading. Molecular dynamics simulations were used to model the surfactant arrangement, geochemical processes in the QAC-clay interlayer, including organic compound sorption and mass transport, as well as the surface electrokinetics of suspended QAC-clay particles. All simulations were carried out based on the combined force field of ClayFF and the Consistent-Valence Force Field to ensure the accuracy of the simulation results, and results yielded insight into the prediction of synthesized QAC-clay behaviors as sorptive material for non-polar organic compounds.