Дисертації з теми "Ciment – Analyse"
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Brisard, Sébastien. "Analyse morphologique et homogénéisation numérique : application à la pâte de ciment." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00617356.
Повний текст джерелаHua, Chongyue. "Analyse et modelisation du retrait d'autodessication de la pate de ciment durcissante." Marne-la-vallée, ENPC, 1992. http://www.theses.fr/1992ENPC9224.
Повний текст джерелаEremia-Georgescu, Georgiana. "Ajout d'une charge minérale et création d'une porosité dans les ciments apatitiques à usage biologique." Toulouse, INPT, 2004. http://www.theses.fr/2004INPT014G.
Повний текст джерелаSaada, Ridha. "Caractérisation bidimensionnelle d'arrangements granulaires par analyse d'image : application à la pâte fraiche de ciment cryosublimée." Toulouse, INSA, 1992. http://www.theses.fr/1992ISAT0016.
Повний текст джерелаDamidot, Denis. "Etude de l'hydratation du silicate tricalcique en suspensions diluées par microcalorimétrie isotherme." Dijon, 1990. http://www.theses.fr/1990DIJOS036.
Повний текст джерелаRoux, Bernard. "Mise au point d'une méthode d'analyse d'images qui reconnait et quantifie les phases de Clinker." Saint-Etienne, 1993. http://www.theses.fr/1993STET4002.
Повний текст джерелаPham, Son Tung. "Etude des effets de la carbonatation sur les propriétés microstructurales et macroscopiques des mortiers de ciment Portland." Thesis, Rennes, INSA, 2014. http://www.theses.fr/2014ISAR0003.
Повний текст джерелаCarbonation is one of the most important factors that initiate the corrosion of steel bars in reinforced concrete. Its kinetics are often used to model the durability of structures. Under the action of carbon dioxide from the air and with the presence of water in the pores, several hydrated phases of the cement paste are carbonated and form calcium carbonate. This process causes a decrease in pH of the pore water, which subsequently induces the depassivation and corrosion of the rebars. Although the carbonation of cementitious materials has been extensively studied in recent years, results in literature about changes in both micro and macroscopic levels are extremely contradictory. The aim of this work is to study the micro and macroscopic effects of carbonation on two standard cement mortars CEM I and CEM II. A wide experimental campaign was conducted on two standard mortars CEM I and CEM II in order to apprehend the physicochemical mechanisms of the carbonation. The following techniques were used to examine the impacts of carbonation on the microstructural characteristics of the cementitious matrix : thermogravimetric analysis, X-ray diffraction, helium pycnometry, nitrogen and water vapor adsorption-desorption. As changes observed in the microstructure could consequently induce significant modifications in the macroscopic properties and the sustainability indicators, we examined the effects of carbonation on the gas permeability, the ultrasonic waves velocity, the thermal conductivity and electrical resistivity. Our work also studied the self-healing effect caused by carbonation of thermally damaged mortars. Finally, our experimental results were used as a database to elaborate a model of the propagation of CO2 in the cementitious matrix
Georges, Valentin. "Comportement de matériaux cimentaires en eau douce naturelle : analyse de l’influence des micro-organismes." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0220/document.
Повний текст джерелаThis work focuses on the behavior of cement pastes of different cement bases exposed to natural fresh water and on the interactions with the biological elements. This study is based on the comparative analysis of samples immersed in natural environment (Moselle) and in artificial laboratory media. Whatever the media and microorganisms considered, the results show a change in the mineralogy of the surface and the porous network of the samples (porosity rate, transfer properties). Laboratory tests highlighted the specific influence of bacteria in bioleaching phenomena. The bacterial count also shows that the density of cells present in the biofilm covering the samples does not mainly depend on the cementitious grade, except for the limestone cements. The SEM observations revealed the abundant presence of diatoms on all samples. Diatoms are partly covered by a mineral layer resulting from secondary crystallization. The colonization of the surface by these diatoms is influenced by the geometry and mineralogical nature of the samples. The results of laboratory tests have shown that they interact with cement paste; the evolution of diatom population densities coincides with changes in porosity characteristics (porosity rate, transfer properties)
Rifaai, Yasser. "Rhéologie des matrices hybrides composées de ciment et d’ajouts cimentaires activés." Thesis, CY Cergy Paris Université, 2020. http://www.theses.fr/2020CYUN1069.
Повний текст джерелаWith the increase of the environmental concerns related to the production of Portland cement, the search for alternatives to achieve sustainable and rational construction is becoming a necessity. Indeed, the production of cement is responsible for the increase in global warming potential (GWP), which questions its widespread use from an environmental point of view. In this perspective, this study aims at reducing the environmental impact of building materials, in particular self-consolidating concrete (SCC). Geopolymers are one of the interesting alternatives that can reduce the environmental impact of construction. However, the incorporation of these materials in the construction markets faces difficulties as long as the understanding of their setting and hardening mechanisms is still a hot topic.The main objective of this thesis is to evaluate the impact of alkaline activator on the setting mechanisms and rheological behaviour of geopolymers based on fly ash, alkali-activated glass powders, and hybrid matrices composed of cement and geopolymers. This study aims to assess the rheological properties and viscoelastic characteristics of these matrices and evaluate the feasibility of incorporating them to design SCC. Coupling the rheological properties with other measures, including Fourier-transform infrared spectroscopy and microstructure, makes it possible to define different mechanisms governing the fresh state of the investigated matrices. The obtained results allowed to identify the optimal concentrations of the alkaline activator to achieve the required rheological properties and mechanical performance. In addition, the methodology used in this study allowed to correlate the rheological properties to the geopolymerization process. This allowed better understanding of the fresh state of these materials. Finally, the incorporation of the optimized pastes into the matrix of SCC was also evaluated. Self-consolidating concrete based on hybrid matrix has shown promising rheological and mechanical performances, as well as a lower global warming potential than conventional SCC proportioned with cementitious materials. These results proved that the use of hybrid SCC offers an interesting solution from an environmental point of view, while achieving the required rheological and mechanical performances
Garcia, Emmanuel. "Approche expérimentale et corrélations dans les systèmes complexes : modes de broyages et réactivités du ciment alumineux fondu." Montpellier 2, 1999. http://www.theses.fr/1999MON20110.
Повний текст джерелаGrandjean, Jérémie. "Formulation et caractérisation de matériaux à base de liants hydrauliques utilisés dans les emballages de transport et de stockage de matières radioactives." Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0012.
Повний текст джерелаROBATEL Industries company designs and products packages for highly radioactive materials. Neutron and thermal protection materials (PNT) are used in those packages to catch neutrons and to limit the increase of temperature due to radioactive materials in case of fire. These PNT are composed of a cement or a gypsum-based matrix with mineral or organic fillers. Once the neutrons have been slowed down by the hydrogen contained in the PNT, a mineral filler named colemanite enables the neutron capture thanks to its high content of boron.The first goal of this thesis is to develop analytical chemistry techniques to check the chemical homogeneity of the PNT, which is crucial, particularly for boron. A dissolution method and two determination techniques have been developed. Another important topic in this thesis is characterization of thermal and mechanical properties. Thermal characterizations include heat of reaction, heat capacity and thermal conductivity measurements to determine the total heat absorbed by the PNT in case of fire. Mechanical characterizations include compression, bending and ultrasonic tests in order to evaluate stress to rupture and elastic moduli of PNT. Beyond the characterizations, the aim of this thesis is to improve pre-existing formulas of PNT and most importantly to propose new formulas. Two mixture designs have been carried out to increase the boron and the hydrogen concentrations of PNT. Another mixture design allowed enhancing the fluidity of a PNT using a superplasticizer. The last part of the thesis deals with the study of new cements called sulfoaluminous that show interesting properties because their hydration products are rich in hydrogen. For these three new PNT families, the increase of the setting time of cement due to boron has been restricted
Nguyen, Dac Loi. "Nouvelle méthodologie d'identification des propriétés mécaniques locales d'un matériau hétérogène par nanoindentation : application aux matériaux du génie civil." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1028/document.
Повний текст джерелаThe present work proposes and develops a complete methodology for identifying the local mechanical properties of a heterogeneous material at the scale of the constitutive phases. It is a combination of very diverse skills in theory, in numerical simulation and in experimentation. More precisely, the theoretical part concerns the determination of the nano-micro relations for the indentation module; the numerical part based on the yield design theory is carried out to find the last relations applicable for the hardness; and the last part is performed to obtain homogenized properties by the experimental way using the nano-indentation technique. The experimental study of the thesis is for the purpose of determining indentation properties of different cement paste samples. A complete experimental program, is developed, which allows characterizing the main phases at the micrometric scale of this material, among which we are mainly interested in the C-S-H matrix phases. The modeling of the problem related to the penetration of an indentation point into a material is studied. For this, the first way, based on the kinematic approach of the yield design theory, consists in trying to construct ruin mechanisms analytically, then to make them evolve according to the change of the initial geometry, in order to obtain the corresponding ultimate load. The second way is then to follow the same approach, but by building numerically these ruin mechanisms. The obtained load depends naturally on the retained criteria parameters, which are determined by the combination with the experimental results. The Von-Mises and Tresca strength criteria for purely coherent materials as well as the elliptical one are examined in this work
Bourissai, Monsef. "Comportement thermo-chimio-hydro-mécanique d'un ciment pétrolier au très jeune âge en conditions de prise HP/HT : approche expérimentale et analyse par changement d'échelle." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00582893.
Повний текст джерелаPlusquellec, Gilles. "Analyse in situ de suspensions de silicate de calcium hydraté : application aux interactions ioniques à la surface des particules." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS046/document.
Повний текст джерелаThis project aims to study the interactions between calcium silicate hydrate (C-S-H) and different anions (chlorides, bromides, nitrates and sulfates) in order to build a thermodynamic model and then be predictable. The simplified system CaO-SiO2-H2O is studied by synthesizing C-S-H suspensions and mixing them with different kind of salts (calcium salt or alkali salt). The influence of the temperature and the presence of aluminum in the structure of the C-S-H is also examined.A classical way to investigate this kind of system is to separate the liquid phase from the solid phase in order to analyze them separately. Nevertheless, this step has a large influence on the system, and the experimental results suffer from a really bad reproducibility.Another analysis method has then been developed in order to avoid the separation of the different phases. The results show that there is no adsorption of chlorides, bromides or nitrate on the surface of the C-S-H. They only have a role as a charge compensator in the diffuse layer around the particles in suspension.The calcium cation (in the case of calcium salt addition) can be adsorbed by C-S-H, but in a small quantity. The substitution of silicon by aluminum in C-S-H doesn’t have any influence on this phenomenon. A higher or lower temperature results in a weaker adsorption, even inexistent.Those experimental results have been reproduced by using a thermodynamic model developed in a previous study. Thus, the validity of the experimental part but also the one of the model are confirmed
Corriveau, Christopher. "Une analyse coût-bénéfice de la cimenterie de Port-Daniel-Gascon." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/34037.
Повний текст джерелаPoussardin, Victor. "Utilisation d'argiles et de marnes calcinées dans le développement de ciments composés." Electronic Thesis or Diss., Ecole centrale de Nantes, 2022. http://www.theses.fr/2022ECDN0040.
Повний текст джерелаThe use of Supplementary Cementitious Materials (SCMs) as a substitute for clinker is a well-known technology that can reduce the environmental cost of cement. Among the SCMs widely used today are fly ash, blast furnace slag and glass powder. In recent years, there has been a growing interest in the use of calcined clays as SCMs, particularly due to their high reactivity and availability.This thesis project focuses on the use of calcined clays and marlstones as supplementary cementitious materials. The main aim is to identify new materials that could be of interest for use as SCMs. To this end, a multi-scale macro/micro approach is used to study the calcination, pozzolanic reactivity and performance in cementitious systems of these new materials. It was possible to demonstrate that marlstones (despite their complex mineralogical composition) have the potential to be used as supplementary cementitious materials after calcination, even with a low proportion of clays. Subsequently, it was shown that palygorskite is a high potential clay for use as a supplementary cementitious material after calcination, and can be considered as a viable alternative to metakaolin. The extensive study of the use of calcined palygorskites as SCMs has also provided new fundamental insights into the understanding of the mechanisms involved in the calcination of this type of material
Ben, Ahmed Karim. "Etude de l'encrassement biologique de matériaux cimentaires en eau de rivière : analyse de l'influence des paramètres de surface des pâtes cimentaires." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAD027/document.
Повний текст джерелаThe biological aspects are generally not considered in the design of civil engineering works, although the biocolonisation may affect their durability. This thesis focuses on biofouling of cementitious materials in river water. A laboratory accelerated test of phototrophic biocolonisation, simulating the river conditions, was developed and validated. It allowed the study of cement pastes of different formulations. Colonization was assessed by the recovery rate of the surface, estimated by a proposed method of image analysis. A study of the roughness influence on the bioreceptivity of the material was conducted through several roughness parameters of different natures, and the peaks density (a spacing parameter) showed the most decisive influence. A model was proposed to explain this influence and gave satisfactory results. The influences of porosity and pH appeared to be limited in the test conditions. Finally, micro-indentation was adapted to the mechanical evaluation of the deterioration of thin layers of cement pastes. This technique may be used to evaluate the biodeterioration
Saussaye, Lucile. "Traitement des sols aux liantshydrauliques : aspects geotechniques et physico-chimiques des pertubations de la solidification." Caen, 2012. https://tel.archives-ouvertes.fr/tel-00800952.
Повний текст джерелаThe reuse of soils after adding binder agents is becoming more and more applied. This treatment technique results in the improvement of the physical and mechanical characteristics of the soils, allowing them to be reused in several geotechnical applications. The technical guides "Soils treatment with lime and/or hydraulic binders", (SETRA-LCPC, 2000 and 2007) present the geotechnical investigation methodologies in the laboratory and in situ. However, the analysis of the experience feedback analysis shows some disturbances such as swelling. This research work investigates the influence of assumed disruptive chemical compounds thanks to: -the physicomechanical and physicochemical characterisation of 3 soils of the Normandy region before and after treatment; -the determination of the thresholds of solidification disturbance due to the presence of anions Cl-, SO42-, NO3-, PO43- in soils. The concentrations thresholds are evaluate both from the mechanical performances and the structural stability point of view. At the microscopic scale, the disturbances are studied by the physicochemical and microstructural analyses of the spiked soils. It seems that the four anions have a disturbance potential. But their influence depends to the soil, the treatment, the chemical form of the anion, its concentration, the cure conditions and the geotechnical test. If the introduction of one single anion in the soil doesn’t prevent a reuse of the treated soil in road construction, the simulations of the anions interactions reveal harmful cases of unsuitability, opening on a new approach on the understanding of the solidification disturbances
Bénézet, Jean-Charles. "Réactivité pouzzolanique dans le système quartz-oxyde de calcium-eau : influence de la dimension et de la température." Montpellier 2, 1997. http://www.theses.fr/1997MON20001.
Повний текст джерелаBaroghel-Bouny, Véronique. "Caractérisation microstructurale et hydrique des pâtes de ciment et des bétons ordinaires et à très hautes performances." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1994. http://tel.archives-ouvertes.fr/tel-00523299.
Повний текст джерелаHe, Huan. "Analyse de l'effet d'un adjuvant biosourcé pour élaborer des matériaux cimentaires plus éco-respectueux." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAD023.
Повний текст джерелаThis work is a part of the SEPOLBE project, which aims to develop eco‐friendly admixtures. The active principle of this admixture is made of extra‐cellular substances, secreted by microorganisms into their surroundings. It contributes to the effort in sustainable development that consists to limit the impact of buildings on environment and human health, with a guarantee of better quality concerning esthetical, durability and resistance criteria, according to the REACH regulation. The action of thisorganic product was evaluated on its setting time effects on cement as well as the mechanical behavior to the hardened state. The bioadmixture presents a significant effect on the workability of mortar (CEM I or CEM V) with a plasticizing action. Whatever the curing time, the compressive strength values of samples containing 1.5% of bioadmixture remain higher than the minimum data of standard strength according to the EN 196‐1 standard. The porosimetry by intrusion with mercury carried out with cement pastes showed the existence of a threshold (in the range 0.5‐0.75% of bioadmixture) from which the porous structure of cement pastes changes, while no modification were observed with the measurement of porosity accessible to water. For higher curing times, thesurface roughness of cement pastes, more heterogeneous, decreases with the presence of the bioadmixture. This work allowed to better control the use of a bio‐product assimilated as an admixture, as well as to contribute to the knowledge of the interactions between microorganisms and cementitious materials. An original approach, using the PCR ‐ not routinely used technique forthat purpose with cementitious materials ‐ helped to highlight that bacteria were present inside the mortar samples with a capacity to grow to higher curing time. The studied bioadmixture allows giving to the concrete the ability to resist against environmental stresses while being eco‐friendly, concerning both its chemical composition and its durability
Cros, Hervé. "Caractérisation morphologique des microstructures de matériaux cimentaires par analyse d'images." Toulouse 3, 1996. http://www.theses.fr/1996TOU30190.
Повний текст джерелаMoustachi, Om Elkhaïat. "Influence de la microstructure des mortiers de ciment portland armes de fibres sur leur comportement mecanique en flexion." Toulouse, INSA, 1986. http://www.theses.fr/1986ISAT0002.
Повний текст джерелаNguyen, Trung-Hieu. "Durabilité des réparations à base cimentaire : analyse comparée de l'influence des propriétés mécaniques du matériau de réparation." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/963/.
Повний текст джерелаSubstrate-overlay composites should work monolithically. For this reason, the durability of a cement-based repair relies also on the durability of its bond with the substrate. To improve the durability of repair, it is necessary to prevent the original cause of debonding: cracks through the depth of the overlay. For this the use of a cement composite having an improved strain capacity should be considered as a suitable solution. The aim of this work is to validate this hypothesis. As repair materials, cement-based mortars incorporating low aggregate stiffness and with fibre reinforcement were used. Rubber aggregates obtained from grinding end of life tyres were used thus contributing to the recovery of an industrial byproduct. Stainless and high bond steel fibres were also used. They are effective to restrain the cracking and can be used in aggressive environment. A good synergy between rubber aggregates and fibres reinforcement is demonstrated: rubber aggregates improve the strain capacity of the composite before the macro-cracking localisation and residual post-peak strength due to the fibre reinforcement is not affected. Monotoneous and fatigue bending tests were carried out on specimens repaired by using these mortars. These tests allow the structural response, in particular the interface debonding, to be analysed (the load corresponding to the debonding initiation and debonding propagation). In parallel, a numerical modelling based on finite element method was conducted to simulate the mechanical response of the tested specimens. Comparison between experimental and numerical results shows the relevance of the numerical modeling which is suitable tool that highlights the effect of the restrained length change of the repair material at the interface on the debonding mechanisms. As ultimate findings, this study shows that a positive synergetic effect from rubber aggregate and fibre reinforcement contributes to enhance the durability of bonded cement-based overlays
Cappelin, Isabelle. "Synthèse de liants pouzzolaniques : application au traitement des sols fins argileux." Toulouse 3, 1992. http://www.theses.fr/1992TOU30280.
Повний текст джерелаEl, Khessaimi Yassine. "Synthesis and hydration of ye’elimite." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0090/document.
Повний текст джерелаA Synthesis and hydration of ye’elimite Ye’elimite-rich cements or calcium sulfoaluminate (CSA) cements are commercialized to prepare shrinkage compensation and self-stressing concretes. Moreover, CSA cements show environmentally friendly characteristics associated to their production, which include reduced CO2 footprint. The expansive behavior of CSA cements is mainly controlled by ettringite amount, produced upon hydration of the key-phase, ye’elimite [Ca4(Al6O12)SO4]. This work presents, on one hand, the optimal conditions for the synthesis highly pure ye’elimite by solid state reactions, and on the other hand, it shows a fundamental description of ye’elimite formation mechanisms. Another aspect of the study encompasses the influence of fineness and citric acid addition on ye’elimite phase dissolution, then on hydrates composition of lab made ye’elimite-rich cement. For the fineness effect study, a highly fine and pure ye’elimite was originally synthetized by sol-gel methods. Various experimental techniques were performed to conduct the different aspects of the present study, namely XRD-Quantitative Rietveld analysis, Thermal analysis (TGA, DTG, DTA and Dilatometry), SEM (BSE imaging and EDS mapping), BET analysis, PSD by laser diffraction, and Image analysis (2D porosity and 2D PSD)
Schittly-Médard, Estelle. "Analyse d'une interface adhérente dentine/titane en fonction de différents matériaux d'assemblage." Thesis, Reims, 2016. http://www.theses.fr/2016REIMO201.
Повний текст джерелаThe aim of this work was to study a bonding dentin/titanium interface. The objective was to optimize and simplify the steps of the bonding protocol, improve and know well the performance of the adhesive interface. In this work, all interfaces have been tested in vitro by shearing.This study included three parts :The purpose of the first study was to evaluate an assemblage by glass ionomer cement (GIC), the Fuji plus®, applied in combination with self-etch bonding system on dentin. Three combinations "system self-etching / Fuji Plus®" were applied and the results obtained by test showed significant improvements from 9% to 44% higher than the values obtained on control specimens.The second experimental part was designed to test the compatibility between five self-etch bonding systems (SEBS) and two resin luting cements (RLC). Significant differences of bond strength in shear were observed according to both the curing mode of the RLC and the adhesive. The SEBS1 proved totally incompatible with chemical or dual cured RLC. Conversely, two-steps SEBS were compatible with RLC chemical/dual cured RLC. A positive correlation was found between the pH of the SEBS or the tested resins and the shear data.The latest study was devoted to evaluate the effect of the storage condition on flexural strength (σf) and shear bond strength (SBS) of a dentin/titanium interface assembled by four self-etch adhesive resin (SEARC). This study showed that the storage in water for 60 days has negatively affected the bending resistance of certain materials. The dentin/titanium adherence offered by Rely X® and G-Cem® was significantly higher than that of Maxcem® and SmartCem2®
Benkemoun, Nathan. "Contribution aux approches multi-échelles séquencées pour la modélisation numérique des matériaux à matrice cimentaire." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2010. http://tel.archives-ouvertes.fr/tel-00657311.
Повний текст джерелаBrockhagen, Dietrich. "Distorsions de concurrence dans un système international de permis négociables : théorie et analyse empirique de l'industrie lourde dans l'Union européenne." Paris, EHESS, 2004. http://www.theses.fr/2004EHES0091.
Повний текст джерелаThe first part develops a theory of distortions of competition among competing firms, induced by differences in the method and/or stringency of national allocation of greenhouse gas emission permits in an international emissions trading system. By applying neoclassical theory on output optimisation, price setting and other factors such as R&D expenditures, five potentially distorting effects are identified for perfect and imperfect markets. The second part develops economic indicators and a two tier approach, which can be applied empirically, in order to test wether an industry is vulnerable to the potential effects found before. The third part applies the two tier approach empirically to four sectors of the energy intensive in the EU : steel making, cement, oil refining and electricity generation. The steel industry is the most vulnerable industry, followed by oil refining, whereas cement and electricity are not vulnerable. At a permit price of 20€/ton CO2, and with national allocations that differ more tha 40% in terms of allowed emissions per ton product output, this thesis predicts that some steel makers would be forced out of the market
Nguyen, Manh Dat. "Modélisation des couplages entre hydratation et dessiccation des matériaux cimentaires à l'issue du décoffrage. Étude de la dégradation des propriétés de transfert." Phd thesis, Paris Est, 2009. http://pastel.archives-ouvertes.fr/pastel-00575355.
Повний текст джерелаSilva, Rogerio Jose da. "Analise energetica de plantas de produção de cimento Portland." [s.n.], 1994. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265129.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-07-19T19:25:46Z (GMT). No. of bitstreams: 1 Silva_RogerioJoseda_D.pdf: 51939278 bytes, checksum: 9b2cad9e3b997c00688f52ad714e3e9b (MD5) Previous issue date: 1994
Resumo: Este trabalho apresenta uma análise energética dos processos de fabricação de cimento Portland, tendo como base a avaliação de eficiência pela 2a Lei da Termodinâmica, em que são aplicados os conceitos de Eficiência Racional e Análise Termoeconômica. No trabalho são discutidas as principais características das matérias-primas utilizadas e as reações de seus compostos na fabricação do clínquer, principal constituinte do cimento Portland, bem como dos combustíveis, que afetam o consumo de energia do processo. As características dos quatros principais processos de fabricação de cimento, quanto à forma de preparação das matérias-primas, consumo específico de calor, e consumo de energia elétrica também são discutidas, obtendo-se subsídios para a análise de eficiência energética. Como resultados são apresentadas as comparações entre as eficiências exergéticas dos processos: de via úmida, de via semi-seca em Fomos Lepol, de via seca em fomo com preaquecedor de ciclones, e de via seca em fomo com precalcinador e preaquecedor. Também são apresentados os resultados da análise termoeconômica para os mesmos processos, em que se compara eficiência exergética, custo exergético unitário, custo da energia por quilograma de cimento produzido, etc. Por fim são comparadas as emissões de poluentes de cada processo, bem como discutidas as formas de atenuação em cada um deles
Abstract: This work presents an energetic analysis of the production processes of Portland Cement, based in the evaluation of the efficiency through the second law of thermodynamics and the concepts of rational efficiency and thermoeconomy. The characteristics of the raw materiaIs, the reactions of their compounds in the clinker manufacturing, and the fuels used are discussed, pointing their relations with the energy consumption in the processo The characteristics of the four main manufacturing processes are discussed, taking into account the preparation of the raw materials, the specific heat and electric energy consumption, getting informations for the energetic efficiency analysis. Results are presented about the exergetic efficiency of the four processes: wet and semi-wet kilns, Lepol kiln, dry process with cyclone preheater and precalciner. The results of the thermoeconomic analysis are presented for the same processes; the exergetic efficiency, the unit exergetic cost, the energetic cost of production, etc. The emissions of the pollutants in each process are shown and the ways of diminishing them are discussed.
Doutorado
Doutor em Engenharia Mecânica
DEQUIEDT, ANNE-SOPHIE. "Contribution a l'etude morphologique des ciments et betons par analyse d'images multimodales." Caen, 1999. http://www.theses.fr/1999CAEN2046.
Повний текст джерелаSaidi, Mohamed. "Mesure et analyse de l'état de déformation et d'endommagement interne dans les composites à matrice cimentaire utilisés pour le renforcement des structures de génie civil." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSE1092.
Повний текст джерелаDue to their mechanical, environmental and aesthetic compatibility, textile reinforced cementitious matrix composites are used on a large scale for rehabilitation and reinforcement of the built heritage and civil engineering structures. Under the effect of mechanical or environmental loads, the phenomena of interaction and damage between the textile reinforcement and the cementitious matrix are more complex than in the case of polymer matrix composites. These are mainly related to the cracking behaviour of the composite, the fragile nature of the matrix and the behaviour of the reinforcement/matrix bond. In particular, knowledge and understanding of the load transfer mechanisms at the reinforcement/matrix interface and crack initiation remain a major scientific challenge.Conventional measurement techniques used to characterise the mechanical behaviour of cementitious matrix composites (mechanical extensometers, digital image correlation, etc.) are able to provide information on the strain and stress state at the surface of a tested specimen. The different mechanisms of internal forces and degradation of the components (reinforcement, matrix, interface) are deduced using approaches of continuum and fracture mechanics.In this context, this work aims at implementing and adapting a measurement system that can be integrated into the core of composites: distributed optical fibre sensors. In order to check its reliability, this measurement technique is coupled with classical extensometer technics such as strain gauges implemented on the surface of the composites and digital image correlation. The main objective is to analyse more precisely the mechanical parameters at the micro scale and the load transfer mechanisms, crack initiation and propagation as well as damage mechanisms. On the basis of uni-axial tensile tests, coupled with the chosen instrumentation, a methodology for identifying local laws of reinforcement/matrix interaction is implemented. The aim of the thesis work is, using these local laws, to determine the micro-mechanical parameters of the composite (load transfer length, shear stress at the reinforcement/matrix interface, etc.) and to establish parameters characteristic of the local and global behaviour (cracking pattern and crack opening, damage indicators, constitutive equations, etc.). Nine configurations are tested and analysed in this work: two types of matrix, two types of textile reinforcement and three reinforcement ratios. The adaptation of the experimental protocol and the reliability of the results obtained are validated. The global and local behaviour of the composite, matrix, textile and their interface are measured and analysed. Load transfer length, shear stress at the textile/matrix interface, interface damage and crack opening are quantified and discussed. The effects of reinforcement ratio, matrix and textile type, mechanical and geometrical parameters of the composite on its mechanical tensile response are identified and evaluated. These results are used for the refinement and/or development of mechanical models of the stiffness and fracture behaviour of textile and cement-matrix reinforced composites
Salvador, Sylvain. "Production de pouzzolanes de synthèse par calcination flash de sols argileux : étude des produits et conception d'une installation." Toulouse, INSA, 1992. http://www.theses.fr/1992ISAT0040.
Повний текст джерелаÇimen, Sarp Güney [Verfasser]. "Kontaktlos Induktive Ladesysteme für Elektrofahrzeuge: Bewertung unterschiedlicher Systemansätze und Analyse der Verlustarten / Sarp Güney Cimen." Aachen : Shaker, 2018. http://d-nb.info/1161299629/34.
Повний текст джерелаNagata, Noemi 1972. "Uso de metodos de calibração multivariada na analise de amostras de interesse industrial e especies de importancia ambiental por fluorescencia de raios-x." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248814.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Doutorado
Ma, Xiaoyan. "Expérience et étude numérique sur la dynamique de transfert d'humidité dans les matériaux cimentaires poreux à plusieurs échelles." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASN025.
Повний текст джерелаClimate change in the last decades is hugely influenced by humans activities including the emission of greenhouse gases. In the construction field, cement production contributes to about eight percent of the world's carbon dioxide emissions, due to the fact that concrete is the most widely used manufactured material in existence. Therefore, the sustainability of concrete and the durability of their structures have significant concerns about global energy consumption and worldwide environmental impact. Research results showed that the structural behavior of concrete is closely related to the variation of water level in concretes and the loss of free water may induce a modification of its elastic properties, strengths, shrinkage, or creep deformations. Thus, the knowledge of the hydric state of concrete is of utmost importance regarding the mechanical behavior and durability potential of concrete structures. From a microstructure perspective, the property of moisture transfer is a manifestation of the internal pore structures. Therefore, it is also important to acquire the knowledge of the pore networks and the pore size distribution over a large range of the material. In this thesis work, we focus on the moisture-transferring mechanisms in concrete, by the combination of the experimental and numerical approach. From the perspective of the drying model and the multi-scale structure of the concrete, we performed the test of drying, imbibition, and drying-imbibition cycling in different geometries of concrete for over 200 days, obtaining the global mass variation and local inner humidity data. The moisture-transferring model contains two major mechanisms: liquid water permeation and water vapor diffusion. Based on the present model and the experimental results obtained, the simulation results of mass loss and relative humidity is calculated in CAST3M, and identification produce of parameters in the model is performed in an optimization program coupled with Matlab. A numerical-experiment-identification coupling method is adopted to simulate drying phenomenon, and the results provide a practical approach in following the moisture transfer process of concrete. Following the parameters optimization, the hypothesis in the moisture-transferring model are discussed as well. The analysis includes the assumptions that are proposed in the model; a simplified analytic solution with the hypothesis of linear coefficient; and the moisture transfer pattern in the model, namely if the two phases (liquid and vapor) of water interact in a parallel, series or combination style, how this influences the humidity profile and mass evolution. The last part of the work is multiple approaches to investigate the inner structure of concrete material, including mercury intrusion porosimetry method (MIP), computational X-Ray tomography, and focused ion beam scanning electron microscope (FIB-SEM). By adopting these three techniques, we obtain the pore size distribution that covers a large range from tens of nanometers to few millimeters. In addition, the 3D volumetric bubble visualization is reconstructed from of X-Rray tomography results
Escoda, Julie. "Modélisation morphologique et micromécanique 3D de matériaux cimentaires." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00741312.
Повний текст джерелаHourdet, Dominique. "Caracterisation physico-chimique de polysaccharides d'origine vegetale : analyse des ciments pectiques au cours de la croissance et du rouissage du lin." Paris 6, 1989. http://www.theses.fr/1989PA066246.
Повний текст джерелаBerger, Carlos Roberto. "Analise da composição inorganica e da liberação de formaldeido apos a manipulação de cimentos endonticos." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288973.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Esse estudo avaliou a composição química da parte inorgânica e a presença de formaldeído em cimentos endodônticos indicados para obturação do sistema de canais radiculares. Sete cimentos endodônticos foram escolhidos: quatro a base de óxido de zinco e eugenol (Targer Canal Sealer - Konne; Endo Fill - Dentsply; Endométhasone N - Septodont e; Pulp Canal Sealer EWT - Kerr); dois a base de agregado trióxido mineral (MTA) (Endo CPM Sealer - EGEO Dental e Obtura - Ângelus) e; um a base de resina/hidróxido de cálcio (Sealer 26, Dentsply). Todos os materiais foram manipulados de acordo com as recomendações de cada um dos fabricantes e inseridos em um porta-amostra de 5 cm de diâmetro e 0,5 cm de altura. Após tomar presa foram analisados através de dois métodos: Difratometria de Raios X, para a análise da parte inorgânica dacomposição química dos cimentos e Cromatografia, para análise da presença de formaldeído. Os resultados demonstraram que: todos os cimentos a base de óxido de zinco e eugenol apresentam óxido de zinco em altas concentrações. Os cimentos Target Canal Sealer e Endo fill, apresentam também na sua composição sulfato de bário e carbonato de bismuto. O cimento Endométhasone N apresentou apenas sulfato de bário e o Pulp Canal Sealer, prata metálica. Já o cimento a base de resina/hidróxido de cálcio, Sealer 26, apresenta óxido de bismuto, hidróxido de cálcio, dióxido de titânio e óxido de ferro. Os dois cimentos a base de MTA testados, Endo CPM Sealer e Obtura, apresentaram basicamente, silicato de cálcio. Componentes tais como: sulfato de bário e carbonato de cálcio foram encontrados no Endo CPM Sealer e hidróxido de cálcio e silicato de magnésio foram encontrados no Obtura. Em relação à presença de formaldeído, todos os materiais testados apresentaram formaldeído após a manipulação. Com base nestes dados, pode-se concluir que: 1) Não houve uma coincidência entre a composição divulgada pelo fabricante e a observada experimentalmente através da Difratometria de Raios X. Exceção a este são os cimentos a base de MTA; 2) apesar de nenhum fabricante indicar a presença de formaldeído na composição do material, este composto foi verificado em todos os cimentos testados, após manipulação.
Abstract: This study evaluated chemical composition (inorganic) and formaldehyde presence in root-canal sealers. Seven root-canal sealers were chosen: four based-zinc-oxide-eugenol (ZOE) (Targer Canal Sealer, Konne; Endo Fill, Dentsply; Endométhasone N, Septodont and; Pulp Canal Sealer, Kerr); two based-mineral trioxide aggregate (MTA) (Endo CPM Sealer, EGEO Dental and Obtura, Ângelus) and; one based-resin/calcium hydroxide (Sealer 26, Dentsply). All materials were mixed according to the manufacturer's instructions and inserted in one matrix (5 cm diameter and 0.5 cm thickness. X-Ray Powder Diffraction and Chromatography was performed after freshly mixed, for chemical composition and presence of formaldehyde, respectively. The results showed that: all ZOE materials presented higher concentrations of zinc-oxide. Target Canal Sealer and Endo fill based-OZE cements, showed barium sulfate and bismuth carbonate in the composition. Endométhasone N cement presented only barium sulfate and Pulp Canal Sealer, metal silver. Bismuth oxide, calcium hydroxide, titanium dioxide and iron oxide were showed in the based-resin/calcium hydroxide (Sealer 26). Both of MTA cements tested, Endo CPM Sealer and Obtura, presented calcium silicate. However, barium sulfate and calcium carbonate was found in the Endo CPM Sealer and magnesium silicate and calcium hydroxide in the Obtura. Regarding to the formaldehyde, all root-canal sealers tested showed this substance after took mixed. It was concluded that: 1) there was a great difference among present results and manufacturer's composition for almost all materials. This was notobserved for MTA root-canal sealers; 2) although no manufacturer has indicated the formaldehyde presence in their material composition, this component was verified in all materials tested.
Doutorado
Endodontia
Doutor em Clínica Odontológica
MASSE-BARBIER, BARBIER SYLVIE. "Synthese hydrothermale d'hydrates de silicate tricalcique analyse structurale en phase solide etude comparative avec les ciments utilises pour chemiser les puits de petrole." Paris 6, 1993. http://www.theses.fr/1993PA066606.
Повний текст джерелаFreitas, Fernando Augusto Ernlund de. "Microfissuração e evolução da hidratação de concreto de cimento portland, com e sem adição de escoria, por meio da analise de imagens." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258266.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil
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Resumo: : As condições de temperatura e umidade durante o período de cura, têm grande influência no desenvolvimento da microestrutura, durabilidade e outras propriedades do concreto. A microscopia eletrônica tem sido usada para analisar as diferenças na microestrutura e no grau de hidratação de amostras submetidas a diferentes tipos de cura. O objetivo deste trabalho foi o de avaliar as características mecânicas, absorção capilar, permeabilidade ao ar, além da evolução da hidratação por meio da análise de imagens de concretos, submetidos a dois tipos de cura: cura térmica à 60°C e cura úmida por sete dias. Nesta pesquisa foram utilizados o cimento Portland de alto-forno (53% de escória), o cimento de alta resistência inicial sem adições (sem adição de escória) e o cimento de alta resistência inicial resistente a sulfatos (27% de escória)
Abstract: Temperature and moist conditions during the curing period have great influence in the development in microstructure, durability and other properties of concrete. Electronic microscopy has been used to analyze the differences in microstructure, degree of hydration and microcracks, on samples submitted to different types of curing. The objective in this research is evaluate the mechanical properties, water absorption, air permeability and the evolution of hydration by image analysis of polished sections of concrete, submitted to two types of curing, steam thermal curing (60°C) and another one, with moist curing during seven days. In this research the blast furnace slag cement was used (53% of slag), the cement with high initial strength without additions (without slag) and the cement with high initial strength with additions (27% of slag). The increase of curing temperature is an activator of slag, present in blast furnace slag cement, than, this research intends to verify the influence of slag addition in the concrete properties
Mestrado
Edificações
Mestre em Engenharia Civil
Fernandes, Celso Peres. "Estudo dos processos de condensação e migração de umidade em meios porosos consolidados. Analise experimental de uma argamassa de cal e cimento." reponame:Repositório Institucional da UFSC, 1990. https://repositorio.ufsc.br/xmlui/handle/123456789/157616.
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O presente trabalho trata de uma análise experimental dos fenômenos físicos de condensação e migração de umidade em um meio poroso consolidado, um tipo de argamassa de cal e cimento, de uso bastante comum no revestimento de paredes externas de edificações. Este trabalho é motivado pelo fato de o comportamento térmico das edificações sofrerem significativas alterações em decorrência da interação entre os processos de transferência de umidade e transferência de calor. Em uma primeira etapa, para a consecução da análise suscitada, procede-se um estudo experimental para a obtenção das isotermas de adsorção e dessorção da argamassa de cal e cimento, com o auxílio de soluções salinas padrões. Em seguida, é feita uma investigação da estrutura porosa da argamassa, através do método de porosimetria com injeção de mercúrio para os poros com raio até 240 A; os poros menores são analisados com o uso da isoterma experimental de adsorção, conjugada ao modelo B.J.H., que leva em consideração os dois modos de condensação da água em um meio poroso: água adsorvida nas paredes dos poros, e água condensada na forma capilar. Em uma segunda parte, deseja-se estudar à migração de umidade (apenas o caso de embebição) em colunas da argamassa de cal e cimento. Para tanto, é necessário o domínio de um método de medição de conteúdo de umidade, que possa ser aplicado em materiais porosos consolidados.
Bernardes, Eduardo Silveira [UNESP]. "Diagênese da Formação Corumbataí na Mina Partezani, Rio Claro - SP." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/102981.
Повний текст джерелаConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
A Formação Corumbataí (Permiano) foi estudada em suas variações verticais, em duas frentes de lavra nas proximidades de Rio Claro, enfocando as relações entre os componentes mineralógicos e as propriedades cerâmicas. A análise petrográfica das amostras coletadas nessas minas, por meio de microscópio óptico, juntamente com Microscopia Eletrônica de Varredura (MEV) dos minerais do cimento e Difração de Raios-X (DRX) com a fração argila, revelou uma assembléia mineralógica complexa com quartzo e feldspato na dimensão silte, matriz constituída por illita, esmectita-clorita, chamosita, berthierina e argilominerais interestratificados, e hematita, calcita e albita como cimento dessas rochas. Os sedimentos originais, pelíticos e ricos em ferro, foram modificados pelos eventos diagenéticos, durante a interação com soluções conatas alcalinas; processos de substituição e autigênese sucederam a diagênese inicial promovendo a formação de diferentes tipos de cimento e o crescimento dos cristais de illita. Os filossilicatos hidratados e amorfos de sílica precipitados na interface sedimento-água deram origem a esses minerais através de transformações associadas à perda de água interplanar e trocas catiônicas com os fluidos hipersalinos iniciais, mas também há evidências de forte influência de eventos magmáticos que teriam desencadeado novas transformações diagenéticas. A diagênese tardia sob influência de processos superficiais sob ação de águas meteóricas também está registrada em algumas feições, embora mais restrita pela característica impermeável dos litotipos. Os principais horizontes estratigráficos foram descritos em termos de litotipo, textura, conteúdo em argila e minerais do cimento. Análise de Componentes Principais e de Agrupamento reforça a correlação entre as feições texturais (granulometria e maturidade) e as propriedades físicas do material.
The Late Permian Corumbataí Formation was studied in its vertical variability within a couple of mine works close to Rio Claro, focusing relationships between mineralogical components and ceramics properties. The petrographic analysis of the samples collected in these mines, made by optical microscopic, Scanning Eletron Microscopy (SEM) of the cement minerals and X-ray techniques with clay fraction, revealed a complex mineralogical assemblage with quartz and feldspar in silt size grains, within a matrix constituted by illite, smectite-chlorite, chamosite, berthierine and interestratified clay-minerals, with cement of hematite, calcite and albite. The original fine-grained iron-rich sediment was modified by diagenetic events, during the interaction with alcalline conate solutions; mineralogical substitution and authigenesis followed this early diagenesis with the formation of different types of cement. The hidrous phyllosilicates and the amorphous silica precipited in the water-sediment interface played an important role on these transformations, but there are evidences of strong influence of magmatic events wich promoted another diagenetic phase generation. The principal stratigraphic horizons were described in terms of lithology, texture, argillaceous content and cement minerals. Principal Components and Clusters Analysis strains the correlation between textural features (grain size and maturity) and physical properties of the material.
Nujaim, Mutaz. "Comportement géomécanique des barricades rocheuses et des remblais en pâte cimentés : expérimentations et modélisations." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0195.
Повний текст джерелаPrecious metals (such as gold and silver), and base metals (such as copper and others) are mined from the underground by excavation, creating voids of various sizes called (stope) which are interconnected by galleries or drifts (for circulation and draw point). In the case of cut-and-fill mining, these voids are usually filled with cemented paste backfill (CPB) which is a mixture made of concentrator mill tailings, of a binding agent (e.g., cement) and mixing water. Since the CPB is placed in the liquid state (solid-liquid suspension) in the underground stopes, it is necessary to use a retaining structure to contain it during backfilling. This retaining structure is called a barricade and can be constructed from wood, concrete, bricks, shotcrete or from waste rock available underground and which come from the drift’s development. Barricades built from waste rock are the most common in Quebec and Canada because they are economical, readily available (underground) and promote water drainage during backfilling, which promotes self-weight consolidation of the CPB, and therefore, reduction of pore water pressure. To date, little information exists on the real in situ characteristics of these barricades (such as their grain size distributions, their failure strength, the probable mechanism of their rupture and the standard dimensions used) to support their design in a meaningful way to ensure the safety of workers and mining equipment, which would contribute to the reduction of the mining cycle, and consequently, to the increase of mining productivity. The work of this thesis project was based on physical and numerical modeling to better understand the complex geomechanical behavior of waste rock barricades. A reduced-scale physical model of a mine stope was developed and constructed from translucent plexiglass plates to simulate backfilling in underground mines. A specific methodology was developed for the execution of the tests: instrumentation of the reduced-scale model using pressure sensors (total and pore water), calibration of the sensors, filling of the reduced-scale model with CPB, continuous monitoring of the tests using high-definition cameras. The tests carried out have made it possible to highlight the main probable mechanism of rupture of the waste rock barricades, as well as the estimation of the maximum pressure at the time of their rupture. The effect of waste rock particle size distribution on the stability and integrity of waste rock barricades due to the CPB pressure was also analyzed. Part of the tests carried out on the reduced-scale model were modeled using the Geostudio 2018 numerical code (GeoSlope Intl.) through calibration with the experimental results. The results of the simulations performed reproduced well the general behavior observed during the tests on the reduced-scale model, but with a significant difference in the pressure values. Simplified analytical solutions based on limit equilibrium have also been proposed based on experimental observations for the stability analysis (with respect to sliding and friction) of waste rock barricades. Some recommendations were proposed to take this study further by including the effect of various factors (e.g., the position of the barricade in the drift or draw point, the viscosity, and the shear yield stress of the backfill or its solids mass concentration, the shear parameters of the waste rock barricades, the arching effect, etc.)
FERREIRA, EDUARDO G. A. "Avaliação da alteração nas propriedades da pasta de cimento em ambiente de repositório." reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10208.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Foppa, Diego. "Analise de variáveis-chave no controle da resistência mecânica de solos artificialmente cimentados." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/7845.
Повний текст джерелаOften, the use of traditional techniques in geotechnical engineering faces obstacles of economical and environmental nature. The soil-cement technique becomes attractive when the improvement of the local soil is a project alternative. The treatment of soils with cement finds application, for instance, in the construction of pavement base layers, in slope protection of earth dams and as a support layer for shallow foundations. However, there are no dosage methodologies based on a rational criteria as it exists in the case of the concrete technology, where the water/cement ratio plays a fundamental role in the assessment of the target strength. In that sense, this study aims to quantify the influence of the amount of cement, the porosity and the moisture content on the strength of a sandy soil artificially cemented, as well as to evaluate the use of a water/cement ratio and a voids/cement ratio to assess its unconfined compression strength. A number of unconfined compression tests, undrained triaxial tests and measures of matric suction were carried out. The results show that the unconfined compression strength increased linearly with the increase of the amount of cement and exponentially with the reduction in the porosity of the compacted mixture. Besides, the change in moisture content has remarkably affected the unconfined compression strength of mixtures compacted in a same dry density. It was verified that, for the soil-cement in the unsaturated state (state usually met by compacted fills), the water/cement ratio is not a good parameter for assessment of unconfined compression strength. In the other hand, the voids/cement ratio, defined by the reason between the porosity of the compacted mixture and the volumetric cement content, adjusted by an exponent, demonstrated to be the most appropriate parameter in the assessment of unconfined compression strenght of the studied soil-cement.
Lorenzetti, Uaçai Vaz. "Avaliação de características associadas à durabilidade de concretos em função da cura, da dosagem e do tipo de cimento." Florianópolis, SC, 2002. http://repositorio.ufsc.br/xmlui/handle/123456789/83421.
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As condições de conservação às quais o concreto é submetido, após sua fabricação e lançamento, podem ser diferentes daquelas especificadas no projeto e desse modo prejudicar as características almejadas, pois o concreto sofre influência particularmente no que diz respeito ao método e à duração de cura. Sendo assim, o objetivo deste trabalho é analisar como os procedimentos de cura influenciam a resistência à compressão, a microestrutura e como contribuem para a durabilidade do concreto de uso corrente.
Yunes, Pablo Rosendo. "Determinação da distribuição de poros de uma argamassa de cimento e cal usando as isotermas de equilibrio e dados de microscopia eletronica." reponame:Repositório Institucional da UFSC, 1992. http://repositorio.ufsc.br/xmlui/handle/123456789/76878.
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O presente trabalho apresenta um estudo sobre a microestrutura porosa de uma argamassa de cimento e cal como a utilizada no revestimento interno de edificações. Materiais como a argamassa são caracterizados por uma distribuição de poros bastante extendida, com diâmetros entre dezenas de angstrons e alguns micrometros. Tal distribuição condiciona seus comportamentos frente aos processos físicos de adsorção e dessorção de vapor e migração de umidade a que estes estão submetidos em sua aplicação cotidiana. Deste modo, duas técnicas complementares são utilizadas para revelar a microestrutura porosa, que possibilite descrever com precisão os processos de fixação e migração de umidade.
Rodrigues, Jose Augusto. "Analise visual do potencial cariostatico in vitro de materiais restauradores associados a aplicação de dentifricios." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289131.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: A prevenção ou paralisação de lesões cariosas adjacentes às restaurações pode ser aIcançada pela correta remoção de placa e utilização de fluoretos tópicos. Para pacientes de alto risco, é ainda recomendado o uso de materiais restauradores cariostáticos, embora ainda não se conheça o verdadeiro efeito da sua associação aos fluoretos. O objetivo deste trabalho foi avaliar, in vitro, o efeito cariostático de 6 materiais restauradores contendo ou não flúor associados à aplicação de dentifrícios em esmalte dental humano. Cavidades classe V foram preparadas no esmalte de 240 fragmentos dentais, aleatoriamente divididos em 12 grupos. Após serem restauradas as cavidades, os fragmentos foram submetidos a ciclos térmicos e de desmineralização e remineralização, simulando um alto desafio cariogênico. Sobre os fragmentos restaurados, ainda, foram aplicados dentifrícios contendo ou não flúor 5 minutos por dia. As diferenças no desenvolvimento de lesões experimentais de cárie adjacente às restaurações foram avaliadas por 5 examinadores calibrados, através de inspeção visual, atribuindo-se escores de 0 a 3. Os resultados foram avaliados pelo teste de Kruskal-Wallis seguido pelo teste de comparações múltiplas (?=0,05). Quando associados ao dentifrício fluoretado, os materiais restauradores não diferiram entre si em relação ao potencial cariostático. Ketac-Fil foi o único material que não diferiu significativamente quando associado com o dentifrício com ou sem flúor. Sob as condições experimentais do estudo, a associação dos materiais restauradores ao dentifrício fluoretado resultou em uma maior ação cariostática, exceto para o cimento de ionômero de vidro, que não diferiu com a aplicação dos dentifrícios
Abstract: The prevention or arrestment of caries lesions around restorations may be done through plaque removal and use of topical fluorides. Restorative materiaIs that release fluoride are still recommended for patients with high caries risk, although the real effect of their association with topical fluorides is not known. The aim of this study was to evaluate, in vitro, the cariostatic effect of six restorative materiaIs that contain fluoride associated with fluoride and non-fluoride dentifrices on human dental enamel. Standardized class V cavities were prepared on 240 enamel fTagments,randomly assigned in 12 groups. After cavity restoration, the fragments were submitted to 1000 thermal cycles, and to demineralization/remineralization cycles, simulating a high cariogenic challenge. During pH cycles, slurries of fluoride and non-fluoride dentifuces were applied for tive minutes after demineralization solution. Artificial caries-like lesions formations were scored independently and blindly by tive calibrated examiners, using a 0 to 3 ordinal scale through visual inspection. The data were evaluated by Kruskal-Wallis test, followed by paired comparisons test (?=0,05). There were no significant differences among restorative materiaIs when associated with fluoride dentifuces. Ketac-Fil was the unique that did not differ when associated with fluoride or non-fluoride dentifrices. Under experimental conditions, the association of restorative materiaIs with a fluoride dentifrice provided better cariostatic effect, except to the conventional glass ionomer cement, whose effect did not change with the dentifrice application
Mestrado
Dentística
Mestre em Clínica Odontológica