Investigators in soils have long recognized the importance of the colloidal fraction of soil, and also the almost inseparable problem of replaceable bases. It is generally accepted that the replaceable base fraction of a colloid controls to a large degree the physical properties exhibited by it. Volumes of work have been written on the problem of controlling the reactions of this fraction and on studies of the properties exhibited by it when it is saturated with various cations. Each worker has proceeded in his own individual way or followed the example set by some previous worker with specific modifications.

Due to the widespread use of drilled shafts in state and federal highway bridges, strict regulation of the design and construction has been imposed by the respective agencies. However, documented cases of anomalies and/or poorly performing shafts continue to arise. To this end, this thesis investigates several aspects of drilled shaft construction that may affect the quality of the finished product. These areas include bentonite slurry properties and performance as well as reinforcement cage and concrete flow interactions. Recent research indicates tremie poured concrete does not flow as predicted. Instead of even rising, a differential between the height of concrete inside and outside the reinforcement cage has been observed. Compounding this problem is the fact that bentonite slurry used to support boreholes may settle suspended sand at the toe of the shaft or on the surface of rising concrete during long wait periods, affording the possibility of soil inclusions in the shaft. This thesis examines two methods of inquiry to quantify the behavior of concrete in a tremie pour drilled shaft and sand suspension behavior of bentonite slurry. Conclusions and recommendations are made to improve pertinent construction regulations to ensure quality of drilled shafts.

This thesis reports on investigations into the influence of diet and a bentonite feed additive on blood parameters in the horse, and the effect of a bentonite feed additive on the process of digestion in the dog. In addition, the methodology of scientific research is examined, and reflections of learning experiences arising from contact with the Hawkesbury approach described. A high-concentrate low-roughage diet, consisting by weight of 70% oats and 30% lucerne chaff, when fed to horses was shown to influence blood red cell levels and blood L-lactate levels compared to three diets of equivalent energy content but reduced proportion of concentrate. Other blood parameters measured included pack cell volume, total plasma protein, total and differential white blood cell count. These demonstrated no significant alteration with diet. The inclusion of bentonite feed additive in a kibble and mince diet fed to dogs was demonstrated to improve the digestion of dry matter and organic matter components of the diet compared to the unmedicated control diet. Inclusion of bentonite food additive in the diet was also associated with an improvement in degree of stool formation and reduction in faecal odour. Part B of the thesis documents the learning experience developed from involvement in the Masters program and reflection on the research studies undertaken. A model for improved reductionist research is described. / Master of Science (Hons) (Systems Agriculture)

Face au problème du devenir des déchets nucléaires, les nations concernées ont envisagé plusieurs stratégies, et ont notamment entrepris l'étude de faisabilité de sites de stockage en grande profondeur ainsi qu'une étude générale sur l'ensemble du problème, tant du point de vue des barrières (géologiques ou ouvragées) que du point de vue des colis radioactifs. Ainsi, les matériaux constitutifs des barrières sont connus dans leurs grandes lignes mais les contacts entre géomatériaux sont susceptibles d'être des zones critiques en terme d'écoulement de fluides. Ce travail de thèse, réalisé au laboratoire 3S, porte sur la caractérisation du comportement hydromécanique de diverses interfaces entre géomatériaux. Les contacts Argilite Mortier et Argilite Bentonite ont été étudiés en compression et/ou en cisaillement hydromécanique, grâce au dispositif de cisaillement BCR3D, afin de dégager les caractéristiques de leur comportement et d'identifier les paramètres ayant une influence sur leur transmissivité. De plus, les essais de cisaillement mettent en évidence le rôle majeur de la rugosité de l'éponte rocheuse et du niveau initial de contrainte normale sur la réponse hydromécanique des interfaces testées. Finalement, certains aspects ont été abordés par des simulations numériques afin d'améliorer notre compréhension des réponses hydromécaniques des interfaces testées.

Afin de valoriser les matériaux présents sur les sites de projets d'infrastructures, le traitement à la chaux est une technique souvent utilisée, puisqu'elle permet d'améliorer les performances mécaniques et la maniabilité des sols. Toutefois, cette technique trouve ses limites avec les sols argileux où les améliorations escomptées ne sont pas obtenues. Afin d'optimiser cette technique et de valoriser les sols argileux, une étude physico-chimique des interactions entre la chaux et les minéraux argileux et un lien avec l'aspect mécanique est donc essentiel pour comprendre comment la chaux interagit avec les minéraux du sol et modifie le comportement macroscopique. Les effets de l'addition de chaux sur le comportement macroscopique de deux argiles (kaolinite et bentonite calcique) ont donc été étudiés. Les résultats montrent que l'ajout de chaux améliore les performances mécaniques des argiles, quelles que soient les conditions hydriques. Ces améliorations sont plus rapides dans le cas de la bentonite. Le couplage entre l'aspect macroscopique et physicochimique montre que les améliorations sont en lien avec la formation de composés secondaires de type silicates, aluminates et carboaluminates de calcium hydratés qui augmentent la cohésion au sein des matériaux. Les améliorations des comportements mécaniques sont d'autant plus importantes qu'il y a de composés secondaires formés. Les caractérisations physico-chimiques montrent également que tous les minéraux rencontrés dans cette étude (kaolinite, muscovite, montmorillonite, feldspaths, quartz,cristobalite) sont modifiés lors du traitement à la chaux.

The current study investigated application of natural adsorbents in brine treatment. Brines are hypersaline waters generated in power stations and mining industries rich in Mg2+, K+, Ca2+, Na+, SO4 2- , Cl- and traces of heavy metals, thus there is a need for these brines to be treated to recover potable water and remove problematic elements. Natural adsorbents have been successfully used in waste water treatment because of their high surface area and high adsorptive properties when they are conditioned with acid or base. The investigation of pH showed that natural adsorbents did not perform well at low pH of 4 and 6. The adsorbents were able to work efficiently at the natural pH of 8.52 of the brine solution. These results show that natural adsorbents hold great potential to remove cationic major components and selected heavy metal species from industrial brine wastewater. Heterogeneity of natural adsorbents samples, even when they have the same origin, could be a problem when wastewater treatment systems utilizing natural clinoptilolite and bentonite are planned to be developed. Therefore, it is very important to characterize the reserves fully in order to make them attractive in developing treatment technologies.

This thesis deals with the diffusion of ions in compactedbentonite clay. Laboratory experiments were performed toexamine in detail different processes that affect thediffusion. To demonstrate that the results obtained from thelaboratory investigations are valid under in situ conditions,two different kinds of in situ experiments were performed. Laboratory experiments were performed to better understandthe impact of ionic strength on the diffusion of Sr2+ and Cs+ions, which sorb to mineral surfaces primarily by ion exchange.Furthermore, surface related diffusion was examined anddemonstrated to take place for Sr2+ and Cs+ but not for Co2+,which sorbs on mineral surfaces by complexation. The diffusion of anions in bentonite clay compacted todifferent dry densities was also investigated. The resultsindicate that anion diffusion in bentonite clay consists of twoprocesses, one fast and another slower. We ascribe the fastdiffusive process to intralayer diffusion and the slow processto diffusion in interparticle water, where anions are to someextent sorbed to edge sites of the montmorillonite. Two different types of in situ experiments were performed,CHEMLAB and LOT. CHEMLAB is a borehole laboratory, where cation(Cs+, Sr2+ and Co2+) and anion (I- and TcO4-) diffusionexperiments were performed using groundwater from a fracture inthe borehole. In the LOT experiments cylindrical bentoniteblocks surrounding a central copper rod were placed in a 4 mdeep vertical borehole. The borehole was then sealed and theblocks are left for 1, 5 or>>5 years. When the bentonitewas water saturated the central copper rod is heated tosimulate the temperature increase due to radioactive decay ofthe spent fuel. Bentonite doped with radioactive Cs and Co wasplaced in one of the lower blocks. Interestingly, the redox-sensitive pertechnetate ion (TcO4-)which thermodynamically should be reduced and precipitate asTcO2·nH2O, travelled unreduced through the bentonite.However, at some spots in the clay, the Tc activity wasconsiderably higher. We ascribe these activity peaks toiron-containing minerals in the bentonite, by which Tc(VII) hasbeen reduced to Tc(IV) and precipitated. The cations Sr2+, Cs+and Co2+, as well as the anion I-, behaved in the CHEMLABexperiments as expected from laboratory studies. Three experiments in the LOT series are completed. The firsttwo diffusion experiments in LOT were less successful, thefirst due to the fact that saturation of the bentonite was notobtained during the experimental period and the radionuclidesdid not move at all. In the second, the uptake of the bentoniteparcel was less successful. Water from the drilling flushedaway large pieces of the top part of the bentonite and thelower part of the test parcel was super-saturated with waterand expanded when released from the rock. The activity distribution in the second experiment wasanalysed. The Co2+ profile looked as we had expected, while Cs+had spread more than our calculations indicated. However, thethird experiment was successful from emplacement, watersaturation and heating to uptake. The activity distribution forboth cations was as expected from laboratory studies. Altogether the three different types of experiments give auniform picture of radionuclide diffusion in bentonite clay forthe ions investigated. / QC 20100621

Ce travail de thèse porte sur l'étude des mécanismes de blocage d'un écoulement d'eau dans un milieu granulaire par injection d'un produit de colmatage, et s'inscrit plus généralement dans la problématique de l'érosion interne des sols (Projet National ERINOH). Cette recherche, à dominante expérimentale, s'appuie sur une modélisation physique unidimensionnelle. Pour cela, une conduite d'écoulement de 18 cm de diamètre intérieur et 300 cm de longueur maximale, constituée par plusieurs tronçons de 50 cm de longueur assemblés, a été développée. Celle-ci est tout d'abord remplie du matériau granulaire perméable à étudier ; on établit ensuite un écoulement d'eau permanent à pression imposée à l'amont ; finalement on vient injecter localement un produit de colmatage pour essayer de bloquer l'écoulement. Le dispositif est équipé de plusieurs capteurs de pression, de débitmètres, d'un turbidimètre afin de mettre en évidence les paramètres significatifs qui contrôlent le processus de blocage. Les paramètres expérimentaux sont les caractéristiques du milieu granulaire (type de sol, conductivité hydraulique, état de compacité...), les caractéristiques de l'écoulement (vitesses, gradients hydrauliques, régime de l'écoulement...), les propriétés rhéologiques du coulis d'injection (densité, viscosité, seuil de cisaillement...) et la technique d'injection associée. Sur la base des résultats obtenus, on propose des critères de blocage de l'écoulement combinant ces derniers paramètres sous une forme suffisamment simple, utilisable dans la pratique, pour répondre à la demande des industriels impliqués dans le projet de recherche ERINOH, qui sont confrontés à ces pathologies

In this thesis study, the use of clay-polymer nanocomposites for their applicability in landfill sites as a product of retardation of waste water infiltration was evaluated. For this purpose, organophilic clays from HDTMA+ organic cation and nanocomposites of montmorillonite were prepared. The bentonite samples B1, B2 and B3 dominantly contain 2:1 layer montmorillonite and 1:1 interstratification of illite/smectite mixed layer as clay minerals. B1 is an unmodified yellow bentonite and B2 is a grey bentonite modified from B1, by the addition of Na2CO3 (Soda Ash). They were obtained from Han&ccedil / ili (Kalecik-Ankara) bentonite deposit which belongs to the Hancili Formation of Early Pliocene age. B3 is a standard Wyoming (SWy-1) white bentonite and belongs to the Newcastle formation of Cretaceous age. Their cation exchange and swelling capacity values were determined and the values increase from B1, B2 to B3. In order to produce clay-polymer nanocomposites, firstly organoclays were produced in bentonite samples. Claypolymer nanocomposite production was achieved by in situ intercalative polymerization successfully with intercalation and partly exfoliation of clay minerals with polyacrylamide (PAM). The samples of sand (S1), sand+bentonite (S2) and sand+nanocomposite (S3) mixtures were prepared and their permeability was determined. As a result of these values, the permeability of samples decrease from S1, S2 to S3. The results imply that the permeability of sample decreases as the claypolymer nanocomposite content increases resulting in a retardation of water penetration throughout the sample. The product has a potential to be used as a retardant for waste water infiltration in landfill sites.

In drilling technologies, Na-bentonite-water mixtures are used as drilling mud. As the reserves of sodium-bentonite decline, calcium or low-quality bentonites are activated with inorganic salts and/or treated with different types of polymers as an alternative to Na-bentonite. The quality of such bentonites, commonly referred to as extended bentonite may deteriorate under severe drilling conditions, such as / bacterial activity, high temperature etc. It was considered that borates could prevent the deterioration of extended bentonites due to their well known bactericide properties. This study involves the use of Na-Borate as an activating agent for bentonites in place of the commonly used Na-carbonate. The effects of Na-borate on the rheological and filtrate behaviours of two different bentonites, namely, Edirne Bentonite (E-Ben) and &Ccedil / ankiri Bentonite (C-Ben) were investigated. The results were evaluated based on API standards and in comparison to those of Na-carbonate activated bentonites. It was found that Na-borate could be used as a bentonite activator, although somewhat higher dosages (3,78% Na2O equivalent for E-Ben and 0,76% Na2O equivalent for C-Ben) than Na-carbonate (2,90% Na2O equivalent for E-Ben and 0,58% Na2O equivalent for C-Ben) are necessary to obtain the same rheological properties. In terms of aging, it was determined that aging had no adverse effect on v the rheological and filtrate properties of bentonite treated with carboxymethyl cellulose (CMC) and polyanionic cellulose (PAC), but rheological properties of bentonites treated with xanthan gum were found to deteriorate upon aging. The presence of Na-borate in the mud appears to alleviate this adverse effect.