Die vorliegende Thesis befasst sich mit der Mischungsentwicklung eines zementreduzierten Ökobetons für die Verwendung in einem ökologisch verbesserten Deckensystem. Dafür wurden mithilfe eines in Microsoft Excel aufgestellten physikalischen Analysemodells – dem Compaction-Interaction Packing Model nach FENNIS – Rezepturen entwickelt, die durch eine optimierte Packungsdichte einen geringeren Zementleimbedarf aufweisen. Dabei gelang es, Zement teilweise durch feine Kalksteinmehle zu ersetzen und eine CO2-sparende Mischung mit einem reduzierten Zementgehalt von 150 kg je Kubikmeter Beton herzustellen, welche die an sie gestellten Anforderungen erfüllt – u. a. bezogen auf Festigkeit (Festigkeitsklasse C 20/25), Verarbeitbarkeit (Konsistenzklasse C3) und Alkalität (pH-Wert > 10). Diese Eigenschaften wurden experimentell geprüft. Zwar wurden bei der auf empirischen Daten beruhenden Prognose von Festigkeit und Konsistenz im Modell nur teilweise realitätsnahe Werte ermittelt, das Modell stellte sich insgesamt jedoch als zielführendes Instrument bei der Mischungsentwicklung von Ökobetonen heraus.:1 Einleitung 2 Verringerung der Umwelteinwirkungen bei der Betonherstellung 3 Methodik der Mischungsentwicklung zementreduzierter Ökobetone 4 Packungsdichteberechnung mit dem Compaction-Interaction Packing Model nach FENNIS 5 Mischungsentwicklung eines Ökobetons im Rahmen des Forschungsvorhabens GRO-COCE 6 Herstellung der Auswahlmischungen und experimentelle Ermittlung von Betoneigenschaften 7 Eingrenzung einer Zielmischung 8 Diskussion der Ergebnisse 9 Zusammenfassung und Ausblick / The present thesis deals with the mix development of a cement-reduced eco-concrete for the use in an ecologically improved ceiling system. For this purpose, a physical analysis model built in Microsoft Excel – the Compaction-Interaction Packing Model according to FENNIS – was used to develop recipes which, due to an optimised packing density, have a low cement paste requirement. It was possible to partially replace cement with fine limestone powders and to produce a CO2-saving mixture with a reduced cement content of 150 kg per cubic metre of concrete, which meets the requirements placed on it – among other things with regard to strength (strength class C 20/25), workability (consistency class C3) and alkalinity (pH-value > 10). These properties were tested experimentally. Although only partially realistic values were determined in the model for the prediction of strength and consistency based on empirical data, the model turned out to be a suitable instrument for mix developments of eco-concretes.:1 Einleitung 2 Verringerung der Umwelteinwirkungen bei der Betonherstellung 3 Methodik der Mischungsentwicklung zementreduzierter Ökobetone 4 Packungsdichteberechnung mit dem Compaction-Interaction Packing Model nach FENNIS 5 Mischungsentwicklung eines Ökobetons im Rahmen des Forschungsvorhabens GRO-COCE 6 Herstellung der Auswahlmischungen und experimentelle Ermittlung von Betoneigenschaften 7 Eingrenzung einer Zielmischung 8 Diskussion der Ergebnisse 9 Zusammenfassung und Ausblick

<p>The term Reclaimed Asphalt Pavement (RAP) is used to designate a material obtained from the removal of pavement materials. RAP is used across the US in multiple applications, largely on asphalt pavement layers. RAP can be described as a uniform granular non-plastic material, with a very low percentage of fines. It is formed by aggregate coated with a thin layer of asphalt. It is often used mixed with other granular materials. The addition of RAP to aggregates decreases the maximum dry unit weight of the mixture and decreases the optimum water content. It also increases the Resilient Modulus of the blend, but decreases permeability. RAP can be used safely, as it does not pose any environmental concerns. The most important disadvantage of RAP is that it displays significant creep. It seems that this is caused by the presence of the asphaltic layer coating the aggregate. Creep increases with pressure and with temperature, and decreases with the degree of compaction. Creep can be mitigated by either blending RAP with aggregate or by stabilization with chemical compounds. Fly ash and cement have shown to decrease, albeit not eliminate, the amount of creep. Mechanical stabilizing agents such as geotextiles may also be used.</p><p><br></p><p><br></p>

Context: The global communication system is in a tremendous growth, leading to wide range of data generation. The Telecom operators in various Telecom Industries, that generate large amount of data has a need to manage these data efficiently. As the technology involved in the database management systems is increasing, there is a remarkable growth of NoSQL databases in the 20th century. Apache Cassandra is an advanced NoSQL database system, which is popular for handling semi-structured and unstructured format of Big Data. Cassandra has an effective way of compressing data by using different compaction strategies. This research is focused on analyzing the performances of different compaction strategies in different use cases for default Cassandra stress model. The analysis can suggest better usage of compaction strategies in Cassandra, for a write heavy workload. Objectives: In this study, we investigate the appropriate performance metrics to evaluate the performance of compaction strategies. We provide the detailed analysis of Size Tiered Compaction Strategy, Date Tiered Compaction Strategy, and Leveled Compaction Strategy for a write heavy (90/10) work load, using default cassandra stress tool. Methods: A detailed literature research has been conducted to study the NoSQL databases, and the working of different compaction strategies in Apache Cassandra. The performances metrics are considered by the understanding of the literature research conducted, and considering the opinions of supervisors and Ericsson’s Apache Cassandra team. Two different tools were developed for collecting the performances of the considered metrics. The first tool was developed using Jython scripting language to collect the cassandra metrics, and the second tool was developed using python scripting language to collect the Operating System metrics. The graphs have been generated in Microsoft Excel, using the values obtained from the scripts. Results: Date Tiered Compaction Strategy and Size Tiered Compaction strategy showed more or less similar behaviour during the stress tests conducted. Level Tiered Compaction strategy has showed some remarkable results that effected the system performance, as compared to date tiered compaction and size tiered compaction strategies. Date tiered compaction strategy does not perform well for default cassandra stress model. Size tiered compaction can be preferred for default cassandra stress model, but not considerable for big data. Conclusions: With a detailed analysis and logical comparison of metrics, we finally conclude that Level Tiered Compaction Strategy performs better for a write heavy (90/10) workload while using default cassandra stress model, as compared to size tiered compaction and date tiered compaction strategies.

Thesis (MScEng (Civil Engineering))--Stellenbosch University, 2008. / There are currently well established compaction methods being used in laboratories globally to prepare specimens for material testing. None of these methods provides the repeatability and reproducibility, ease of execution or simulation and correlation to field compaction desired by engineers. The research presented in this report was aimed at the development of a new or adapted compaction method for bituminous stabilized materials (BSM) that would address the aforementioned factors, by making use of a vibratory hammer. Along with this, a new protocol was to be established. The initial vibratory hammer that was tested was the Kango 637®. This specific vibratory hammer suffered irreparable damage to the gearbox during the research. A replacement Kango hammer could not be purchased, therefore a substitute hammer was purchased i.e. a Bosch GSH 11E®, for which back-up service and replacement parts are readily available throughout South Africa. Significant progress had been made with the development of a laboratory compaction protocol for BSM using the Kango Hammer. The specifications of the Bosch® hammer showed it was superior in terms of power, weight and other technical features. Comparative testing was therefore carried out. This allowed for the adaptation of the results achieved to that point. Extensive experimentation was then carried out using two types of BSM i.e. foamed bitumen (80/100 bitumen) and bitumen emulsion (60/40 Anionic Stable Grade) stabilized material. The initial material used for the experimentation was a G2 quality graded crushed stone. Additional material was also obtained from a recycling project taking place along the N7 near Cape Town. The N7 material was used to perform correlation experiments so as to determine how representative the laboratory compacted specimens were to field compacted material. Results showed that the vibratory hammer is capable of producing specimens for testing in the laboratory as well as providing a possible benchmark method for accurately controlling the quality of work on site i.e. field density control. This was done by identifying the time to and level of refusal density compaction. The level of refusal density compaction was expressed as a percentage of Mod AASHTO compaction and using current specifications, a potentially new site compaction level specification was determined. In order to asses the material applicability of the vibratory hammer compaction method, tests regarding moisture sensitivity analysis were carried out on a G5 material. The vibratory compaction protocol includes a specification for the type of hammer, guide-frame, surcharge weight, compaction moisture and number of layers. Vibratory compaction can be used to prepare two types of specimens: • Specimens for triaxial testing with a diameter of 150mm and a height of 300mm • Specimens for laboratory testing with a diameter of 150mm and a height of 125mm. Tests showed that the material properties prove to have an influence on the compactability of the material. Material from the N7 recycling project had been milled out thus altering the grading and including some RAP. This in turn influenced compaction. The vibratory hammer moisture curve was found to shift slightly to the left when compared to the Mod AASHTO moisture curve. The variability of the vibratory hammer was found to be well below the specified variability of 15%. Repeatability experiments on G5 material indicate that vibratory hammer compaction may be used on lesser quality granular materials. A recommended procedure for the compaction of BSM was developed following the experimentation results.

La compaction isostatique a chaud (cic) permet de produire des pièces céramiques de forte densité avec des microstructures homogènes. Pour mieux comprendre les processus de densification et pour être capable de prévoir les formes finales, des équations constitutives tenant compte du comportement mécanique et des évolutions microstructurales, ont été developpees et introduites dans un code de calcul utilisant la méthode des éléments finis. Les expériences ont été menées sur une poudre d'alumine pure, considérée comme un matériau modèle. Une alumine renforcée par des whiskers de sic ainsi qu'une poudre de diborure de titane ont également été étudiées. Des pièces céramiques tests ont été réalisées et comparées aux résultats de simulations afin de valider les équations constitutives proposées.

<p>There are today strong incentives for an increased understanding of material properties and manufacturing processes to facilitate the development of new technologies in the pharmaceutical industry. The purpose of this thesis was to suggest methods requiring a low sample amount for characterization of technical properties of powders.</p><p>Compression analysis was used to evaluate the formulation relevance of some compression equations. Using the mechanics of single granules to estimate powder functionality was part of this work. It was concluded that the formability of granular solids and the plasticity of single granules could be determined with compression analysis by using the Kawakita model for single components and binary mixtures of ductile granules.</p><p>Further on, the fragmentation propensity of solid particles could be estimated from compression analysis by using the Shapiro equation, enabling indicators of both the fragmentation and the deformation propensity of particles to be derived in one single compression test.</p><p>The interpretations of the compression parameters were only valid if the influence of particle rearrangement was negligible for the overall compression profile. An index indicating the extent of particle rearrangement was developed and a classification system of powders into groups dependent on the incidence of particle rearrangement was suggested as tools to enable rational interpretations of compression parameters.</p><p>The application of compression analysis was demonstrated by investigating the relevance of the mechanics of granular solids for their tableting abilities. The plasticity of single gran-ules was suggested to influence both the rate of compactibility and the mode of deformation, and consequently the maximal tablet strength. The degree of granule bed deformation was shown to be a potential in line process indicator to describe the tableting forming ability.</p><p>This thesis contributes to a scheme, suitable in formulation work and process control, to describe manufacturability of powders for an enhanced tablet formulation technology.</p>

Les affleurements de Bevons, Nyons et Rosans dans le Sud-Est de la France, comme ceux du Numidien (Sicile, Tunisie, Maroc...) ou de la Tourelle (Canada) permettent l'observation de nombreuses injectites sableuses alimentées par des chenaux turbiditiques. Deux types d'injectites sont présents : les sills (horizontaux) et les dykes (verticaux), les dykes étant issus des sills. Leurs processus de mise en place sont, selon les auteurs, per ascensum, post-dépositionnels, et (sans doute le plus souvent) per descensum, contemporains de la mise en place du sable nourricier et objet de la présente étude. L'approche des mécanismes intervenant dans cette fracturation et la modélisation de celle-ci ont notamment pour but de préciser l'évolution de l'étanchéité des matériaux argileux pouvant constituer un site de stockage de déchets. D'un autre point de vue, des injections sableuses étant localisées entre des réservoirs contenant des hydrocarbures, une détermination de leur géométrie est nécessaire pour prédire les circulations potentielles de fluides durant la production. Un modèle géométrique a été établi à partir de ces observations et a permis de faire certaines hypothèses sur les mécanismes à prendre en compte dans les modélisations de cette fracturation et/ou injection. Plusieurs approches sont menées en parallèle : - L'étude de la compaction dans le massif, avant l'injection : pour des concentrations en sable assez élevées (> 35 %), le poids de la colonne de mélange d'injection est supérieure à la contrainte verticale dans la partie superficielle du massif. Cette inversion de densité peut être responsable du fait que l'injection se propage plutôt vers le bas dans le cas des dykes ou le long de discontinuités stratigraphiques (telles que les niveaux de cendres par exemple). Lorsque l'on descend dans les sédiments, la pression dans la colonne de mélange sableux varie linéairement avec la profondeur alors que la contrainte dans les sédiments varie non linéairement (issue d'une courbe de porosité en exponentielle). A partir d'une certaine profondeur, la pression fluide devient inférieure aux contraintes dans la succession sédimentaire : l'injection ne peut pas dépasser cette profondeur. Ainsi, la propagation des dykes est limitée par le poids de son encaissant. - L'utilisation de la fracturation hydraulique comme mécanisme de l'injection : la mécanique des roches et plus précisément les mécanismes d'hydrofracturation ont été testés pour tenter de modéliser ces observations à grande échelle. La force responsable de l'initiation et de la propagation des fractures est la pression due à la mise en place du chenal turbiditique. Le modèle tient compte du fait que l'injection doit soulever les terrains sus-jacents. Les premiers résultats ont permis de montrer que dès qu'une fracture horizontale est initiée, la propagation est rapide. L'ouverture obtenue (épaisseur d'un sill) est décamétrique, soit du même ordre de grandeur que les observations de terrain. - L'utilisation d'un fluide à seuil dans un réseau établi, avec des probabilités cohérentes avec la réalité des phénomènes entrant en jeu, a permis de déterminer les extensions maximales d'injection en accord avec les observations de terrain : - Un sill seul peut se propager sur 2400 m en quelques dizaines d'heures, - Un dyke seul peut descendre jusqu'à 400 m sous le paléofond de mer en quelques secondes, - Un réseau de sills et de dykes connectés (ce réseau étant connecté au chenal par un sill) peut avoir une extension horizontale de 1200 m et verticalement de 400 m, et se mettre en place en quelques heures. La formation des sills est plus longue que celle des dykes, la formation d'un sill seul dure plusieurs heures alors que celle d'un dyke dure quelques secondes. Lorsque les sills et les dykes sont connectés, le temps de propagation du réseau est d'environ 2 heures. Les dykes se forment toujours en quelques secondes et ont un effet sur la propagation des sills qui se propagent deux fois moins loin que s'ils étaient seuls.

On s'est intéressé dans ce travail à la modélisation 2D et 3D du procédé CIC (Compaction Isostatique à Chaud) à l'échelle mésoscopique, en vue d'une compréhension approfondie des différents mécanismes physiques impliqués dans la densification de poudre. Le modèle est formulé dans un cadre eulérien, et est basé sur l'utilisation de la méthode level-set couplée avec une technique de génération et d'adaptation de maillages éléments finis afin de modéliser la déformation des particules de poudre sur un Volume Élémentaire Représentatif (VER). La génération des particules a été effectuée avec un générateur statistique de microstructures en tenant compte d'une distribution réelle de la taille des particules. Les conditions aux limites mécaniques ont été appliquées sur le VER, entraînant la déformation des particules et la densification du VER. Dans ce travail, la déformation viscoplastique des particules a été considérée comme le seul mécanisme de densification (mécanisme prépondérant pour une grande partie du temps du procédé). A partir de données issues de simulations macroscopiques du mécanisme CIC pour le cas de particule de poudre 316L, des simulations mésoscopiques ont été réalisées (approche macro-méso). Les résultats de ces simulations sont présentés et discutés à la lumière d'une étude expérimentale (microscopie optique, MEB, EBSD et EPMA) de la structure et microstructure des particules, obtenues à partir d'essais de compactions interrompus. De plus, des essais mécaniques ont été réalisés à température ambiante sur des lopins totalement denses issus du procédé CIC.Mots clés : CIC, 316L, compaction de poudre, fonction level-set, génération et adaptation de maillages, échelle mésoscopique, étude expérimentale, microstructure, EBSD, essais mécaniques. / A two and three-dimensional finite element simulation of HIP (Hot Isostatic Pressing) at mesoscopic scale is proposed, in view of an in-depth understanding of the different physical mechanisms involved in powder densification. The model is formulated in a eulerian framework, using level set formulation and adaptive meshing and remeshing strategy to identify particle interactions inside a representative elementary volume (REV). A statistical generator is in charge of the definition of the initial configuration under the constraint of accounting for the real particle size distribution. Mechanical boundary conditions are applied to the REV, resulting in the deformation of particles and densification of the REV. As a first approach, the power-law creep of particles is considered as the unique densification mechanism. Starting from data issued from macroscopic simulations of the HIPping of a part made of 316L powder, mesoscopic simulations in different locations of the part have been carried out (macro-to-meso approach). The results of these simulations are presented and discussed in the light of experimental studies (optical microscopy and SEM, EBSD, EPMA) of the structure and microstructure of the compact, which were obtained from interrupted compactions. Mechanical tests on fully densified 316L were also conducted.Keywords : HIP, 316L, powder densification, level-set function, meshing and remeshing technique, mesoscopic scale, experimental studies, microstructure, EBSD, mechanical tests.

This work deals with the possibility of use of intelligent methods in construction machines control. These methods are based on GPS in combination with using laser and ultrasonic technology. There is in detail described especially control by robotic total station and 3D control, which includes digital model of construction site. The new trends of control are especially applied on the vibratory rollers. There are taken into consideration: achievement of sufficient degree of compaction on the basis of on-line information about conditions of subsoil.

Despite applications of foamed bitumen technology in pavement construction in various places around the world, there are still several aspects about this technology that are not clear. In addition, knowledge on foamed bitumen technology is mainly empirical and lacks scientific basis. This study addresses some of the aspects for foamed bitumen technology such as: Investigation of any effects in binder composition during the production process for foamed bitumen; assessment of the effect of bitumen source on foamed bitumen characteristics; development of a rational method to optimise foamed bitumen characteristics and conditions; evaluation of aggregate particle coating within foamed bitumen mixes; further improvements in the mix design procedure specifically the method of compaction and optimum bitumen content determination stages are suggested.  Fourier transform infrared spectroscopy techniques were used to investigate any changes in bitumen composition after the production process of foamed bitumen. Fourier transform infrared tests were done on foamed bitumen and neat bitumen specimens for two bitumens with similar penetration grades. Foamed bitumen characteristics of three bitumens were established by producing foamed bitumen at temperatures of 150ºC up to 180ºC and foamant water contents of 1, 2, 3, 4 and 5%. From the analysis of variation of foamed bitumen characteristics (maximum expansion ratio and half-life) at different temperatures a new method based on the equi-viscous bitumen temperature to optimize foamed bitumen conditions and characteristics was proposed. Rice density and surface energy concepts were used to evaluate aggregate particle coating with foamed bitumen. A granite aggregate divided into three different size fractions and three sets of foamed bitumen produced from three bitumen penetration grades were used. A gyratory laboratory compaction procedure for laterite gravels treated with foamed bitumen was established using the modified locking concept. Three laterite gravels with different chemical composition were mixed with foamed bitumen produced from one penetration bitumen grade. The resulting mixes were compacted up to 200 gyrations and the corresponding compaction curve defined in terms of height versus number of gyrations noted. In addition, the optimum moisture content requirements at the modified locking point were determined. 3D packing theory concepts, primary aggregate structure porosity and an indirect tensile strength criteria were employed to determine optimum bitumen content for foamed bitumen mixes.  Fourier infrared techniques revealed that foaming did not cause any changes in the bitumen chemistry, implying that the foamed bitumen production process may possibly be a physical process. Characterisation of foamed bitumen produced from three bitumen penetration grades showed that foamed bitumen characteristics (maximum expansion ratio and half-life) were mainly influenced by binder viscosity rather than the source. The equi-viscous temperature seemed to provide a suitable criterion at which foamed bitumen with optimum characteristics could be produced. Rice density results showed that aggregate size fraction, binder expansion ratio and viscosity influenced aggregate particle coating. For the coarser aggregate fraction, results revealed that binder coating seemed to be mainly influenced by temperature. Whilst for fine aggregate fraction the coating was mainly influenced by surface area. Surface energy results revealed that foamed bitumen exhibited better coating attributes than neat bitumen. A new laboratory compaction procedure for laterite gravels treated with foamed bitumen based on the modified locking point was developed. The modified locking point represents the state at which maximum aggregate particle interlock occurs when mixes are compacted in the field. It is based on the iii analysis of the rate of change for the gyratory compaction curve. The compaction curve in this case is defined in terms of compaction height versus number of gyrations. Gradation analysis beyond the modified locking point showed that aggregate particle breakdown occurred. Analysis of the optimum moisture at the modified locking point revealed that the moisture conditions were less than the aggregate optimum moisture conditions. It is recommended that this point be used to determine the optimal compaction characteristics of foamed bitumen mixes.  Aggregate structure porosity and an indirect tensile strength criteria can be used to determine the bitumen content that could be used in design of foamed bitumen mixes. This would reduce the amount of resources required since the bitumen content could be estimated prior to carrying out the actual laboratory work given that the aggregate grading is known. The aggregate structure can be divided (based on 3D packing theory) into oversize, primary, and secondary structures. The primary structure is mostly responsible for carrying loads whilst the secondary structure fills the voids within the primary structure and provides support to the primary structure. The aggregate size particles constituting the primary structure are deduced as a function of standard sieve sizes using the packing theory concepts. The minimum sieve size for the primary structure is proposed as 1 mm. The oversize structure consists of aggregate particles whose size is greater than the maximum size for the primary structure. The secondary structure consists of aggregate particles whose size is below the minimum size for the primary structure. The primary aggregate structure porosity can be used to establish the starting bitumen content; the bitumen content at which this porosity is 50% is chosen as the initial bitumen content. Indirect tensile strength values corresponding to 50% primary porosity are determined as well as the bitumen contents and compared against the recommended minimum values. / <p>QC 20161012</p>