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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Temperature Effect On Calcium Aluminate Cement Based Composite Binders

Kirca, Onder 01 August 2006 (has links) (PDF)
In calcium aluminate cement (CAC) systems the hydration process is different than portland cement (PC) systems. The hydration products of CAC are subjected to conversion depending on temperature, moisture, water-cement ratio, cement content, etc. Consequently, strength of CAC system can be seriously reduced. However, presence of other inorganic binders or additives may alter the hydration process and improve various properties of CAC based composites. The objective of this study is to investigate the temperature effect on the behaviour of CAC based composite binders. Throughout this research, several combinations of CAC-PC, CAC-gypsum, CAC-lime, CAC-ground granulated blast furnace slag (CAC-GGBFS) were studied. These CAC based composite binders were subjected to seven different curing regimes and their strength developments were investigated up to 210 days. In addition, the mechanism of strength development was examined by XRD analyses performed at 28 and 210 days. Finally, some empirical relationships between strength-time-curing temperatures were formulated. Experimental results revealed that the increase in ambient temperature resulted in an increase in the rate of conversion, thereby causing drastic strength reduction, particularly in pure CAC mix. It has been observed that inclusion of small amount of PC, lime, and gypsum in CAC did not induce conversion-free CAC binary systems, rather they resulted in faster conversion by enabling rapid formation of stable C3AH6 instead of metastable, high strength inducing CAH10 and C2AH8. On the other hand, in CAC-GGBFS mixes, the formation of stable straetlingite (C2ASH8) instead of calcium aluminate hydrates hindered the conversion reactions. Therefore, CAC-GGBFS mixes, where GGBFS ratio was over 40%, did not exhibit strength loss due to conversion reactions that occurred in pure CAC systems.
32

Effects Of Separate And Intergrinding On Some Properties Of Portland Composite Cements

Soyluoglu, Serdar 01 January 2010 (has links) (PDF)
In the production of cement, to increase the cement/clinker ratio and decrease CO2 emission, the most important alternative is to produce mineral admixture incorporated cements (CEM II-III-IV-V) instead of portland cement (CEM I). These cements are usually produced by intergrinding the portland cement clinker and the mineral admixtures. However, the difference between grindabilities of the different components of such cements may cause significant effects on the particle size distribution and many other properties. For this reason, separate grinding of additives and clinker may be thought as an alternative. In this study, the effects of intergrinding and separate grinding on the particle size distribution and consequently on the strength of portland composite cements which contained natural pozzolan (trass), granulated blast furnace slag (GBFS) and limestone besides portland cement clinker were studied.
33

DESEMPENHO DO CIMENTO PORTLAND BRANCO COM ESCÓRIA DE ALTO-FORNO E ATIVADOR QUÍMICO FRENTE AO ATAQUE POR SULFATO DE SÓDIO / PERFORMANCE OF A WHITE PORTLAND CEMENT WITH SLAG AND CHEMICAL ACTIVATOR AGAINST SODIUM SULFATE ATTACK

Veiga, Karina Kozoroski 31 August 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Sulfate ions found in seawater, groundwater and wastewater are aggressive agents that can result in severe concrete degradation. They react with cement hydration products and depending on the associated cations present (magnesium, calcium, potassium, sodium, ammonium), their concentrations and the conditions of the environment, this can result in the formation of ettringite, gypsum or thaumasite, decalcification of C-S-H, processes which may cause expansion, cracking and loss of mass and strength.When high sulfate resistance is required, national and international standards prescribe the use of cement with high concentrations of granulated blast furnace slag (GBFS). By substituting GBFS for cement, lower amounts of clinker are required. In addition, the pozzolanic activity of GBFS takes up the CH released by the hydration of silicates (C3S e C2S), which then is not available to react with sulfate ions to form gypsum, resulting in a more dense paste with lower penetrability. GBFS is one of the few mineral admixtures that can be added to white Portland cement (WPC), a material with widespread usage in civil construction, particularly in cases where concrete is used as a finished surface for architectural impact. The substitution of GBFS for WPC offers technical and environmental gains as well as economic advantages due to the higher cost of WPC. This study investigated the sulfate resistance of WPC with 0%, 50% and 70% GBFS as a substitution for cement. A mix with 50% GBFS that was chemically activated with Na2SO4 (4% b/w of binder) was also studied. The performance of the blended cements was monitored by exposing the prepared mortar specimens to a solution of Na2SO4 (5%) for 2 years according to ASTM C1012/04 and using TG/DTA, DRX and SEM/EDX analyses of the paste samples. For comparison, the same blends prepared with high early strength Portland cement (PC) were also used. The results showed the benefits of the use of GBFS in both types of cement, with higher concentrations of slag resulting in improved sulfate resistance. The use of chemical activation reduced expansion when compared with mixtures without activation. For long-term exposure, all WPC blends showed lower expansion than the corresponding blends with PC. Microstructural analysis identified ettringite and gypsum as the main degradation products of the sulfate attack. / Os íons sulfato, encontrados na água do mar, em águas subterrâneas e em águas residuárias são agentes agressivos que podem levar a uma severa degradação do concreto. Ao reagirem com os produtos de hidratação do cimento, dependendo do tipo de cátion a que estão associados (magnésio, cálcio, potássio, sódio, amônio, etc.), da concentração e das condições do meio, podem levar à formação de etringita secundária, sulfato de cálcio, taumasita, descalcificação do C-S-H, podendo ocorrer expansão, fissuração, perda de massa e de resistência. Quando se faz necessário assegurar uma elevada resistência ao sulfato, a normalização nacional e internacional, dentre outras recomendações, especifica o uso de cimento com elevados teores de escória de alto-forno. Além da redução da quantidade de clínquer ocasionada pela substituição do cimento por escória, a atividade pozolânica da mesma consome o CH liberado pela hidratação dos silicatos (C3S e C2S), que não fica disponível para reagir com os sulfatos e formar sulfato de cálcio, e promove a densificação da matriz, reduzindo a penetrabilidade do meio. A escória é também uma das poucas adições que podem ser incorporadas no cimento Portand branco (CPB), que vem se tornando uma nova tendência dentro do contexto da construção civil, quando se opta por concreto aparente em obras com forte apelo arquitetônico. Além das vantagens técnicas e ambientais, a substituição do cimento branco por escória possibilita a redução do custo bastante elevado do CPB. Neste estudo, investigou-se a resistência ao sulfato de sódio do CPB com teores de substituição de escória de alto-forno de 0%, 50% e 70%. Também foi investigada uma mistura com 50% de escória ativada quimicamente por Na2SO4 (em teor de 4% em massa do material aglomerante). O desempenho dos cimentos foi avaliado pela exposição de argamassas em solução de 5% de Na2SO4 por dois anos, de acordo com a ASTM C1012/04 e através de análise de DRX, TG/DTA e MEV/EDS em pastas. Para comparação foram investigadas as mesmas misturas compostas com cimento Portland de alta resistência inicial, CPV-ARI. Os resultados mostraram os benefícios do uso da escória em ambos os cimentos, sendo que o acréscimo do seu teor aumentou a resistência ao ataque por sulfatos. A ativação química reduziu a expansão comparativamente às misturas sem ativador. A longo prazo, todas as misturas com o CPB apresentaram menor expansão do que aquelas com CPV-ARI. A análise da microestrutura identificou a etringita e o sulfato de cálcio como os principais produtos de degradação por sulfato de sódio.
34

Investigação de parâmetros do CCR com incorporação de escória granulada de alto forno para utilização como base de pavimentos. / Analysis of mechanical behavior of the RCC with incorporation of granulated blast furnace slag for use as pavement base.

Paulo César Pinto 19 February 2010 (has links)
A crescente preocupação ambiental e a atual crise energética fazem com que indústrias, de um modo geral, intensifiquem esforços para maximização de processos de produção e reutilização de subprodutos gerados. Na siderurgia a produção do aço é realizada por meio da extração do minério de ferro adicionando-se fundentes, gerando como subproduto uma ganga em forma de escória de alto forno. Na presente pesquisa foram compostas misturas de concreto compactado com rolo CCR visando o emprego como base de pavimentos, utilizando três diferentes materiais de granulometria miúda: areia natural, areia industrial e escória granulada de alto forno (com dimensão máxima de 4,8 mm) nas quantidades de 50 % e 100 %; para fins de análise da influência destas diferentes areias foram confeccionados corpos de prova cilíndricos e prismáticos moldados na umidade ótima e no ramo seco da curva de compactação. Foram investigados parâmetros referentes à umidade de compactação, massa específica, resistências à tração indireta e à tração na flexão, módulos de elasticidade por pulso ultrassônico, além de módulos de elasticidade estáticos obtidos a partir de curvas tensão-deformação e por analogia de Möhr (medida de flecha em vigotas em flexão). Visando avaliar a aplicabilidade dos CCR estudados, em especial aquele com escória, foi utilizado o programa computacional MnLayer (para análise de tensões em pavimentos asfálticos) empregando camada de base rígida em CCR para estruturas de pavimentos sujeitos à ação de cargas do tráfego de veículos rodoviários, portuários e aeroportuários, observando a influência dos três tipos de agregados miúdos no nível de tensões da camada cimentada, o que depende em grande parte do módulo de elasticidade da camada de base. Observou-se queda nas resistências dos CCR quando da incorporação de 50 % ou 100 % de escória granulada; por outro lado, essas misturas apresentaram ganhos de resistência em idades mais avançadas em comparação a misturas que empregaram areias natural ou industrial. O módulo de elasticidade dos CCR, com a presença da escória, parcial ou total como fração areia, em geral decresceu à exceção de seu emprego em conjunto com areia natural. As misturas com escória granulada, do ponto de vista de análise mecanicista, resultaram em exigências de maiores espessuras do material, o que não pode fazer tal mistura economicamente viável em qualquer situação, para os casos de misturas com 100 % de escória granulada de alto forno e com fração mista de areia natural e escória. / The increasing environmental concerns as well as energy sources shortage leads industry to consider both optimization of production processes and sustainable use and disposal of its by-pass products. In siderurgical steel manufactures the most common by-pass product is the blast furnace slag with emphasis to its granulated shape. This study considered the evaluation of rolled compacted concretes (RCC) mixtures containing natural or industrial sands as well as such slags at 50% and 100% (with maximum diameter of 4.8 mm) as candidates for pavement base layers. The analysis considered laboratory compaction tests in order to verify the influence of such sands on concrete physical parameters as bulk density and optimum moisture content. Evaluation of mechanical parameters as indirect tensile strength, flexural strength, ultrasonic modulus of elasticity and static modulus of elasticity were carried out as part of the study. Through mechanistic analysis using the elastic layered theory-based computational program MnLayer it was possible to verify implications of each RCC mixture design on pavement thickness and tensile stresses in cemented base layers, in consideration of highway, harbor and airport vehicles. Loss of resistance was verified for RCC mixtures at 50% and 100% slag sand; on the other hand such mixtures have improved its strengths at advanced ages (180 days) compared to the other sands. The modulus of elasticity also decreased for mixtures containing slag sands with exception to the blend of natural and slag sand. Under the mechanistic stand point slag sand mixtures requires thicker base layers in pavements that could lead, depending on several factors, to less cost-effective results in the case of 100% slag sands mixtures and blend (50%-50%) natural and slag sands mixtures.
35

Characterization of Different Slags for Bulk Geotechnical Applications

Logeshwari, J January 2017 (has links) (PDF)
Generation of wastes in the form of liquid, solid or gas is inevitable in any industry.Industrial Solid Waste is the waste that is generated from an industrial or manufacturing process and includes the waste generated from non-manufacturing activities as well.Most of these wastes fall under the category of Ashes, Slagsor Sludges. For the present work, three types of secondary lead slag, two types of granulated blast furnace slag (GBS) or iron slag and four types of steel slags were procured and studied.An elaborate study on various characteristics of the slags has been performed. Based on the results, all the possible applications for the individual slags are considered. The performance of the secondary lead slag as an embankment material was analyzed. The slope stability for various conditionswas analyzed using Geo5 and experimentally determined strength parameters. It was found that the material can be used safely for embankment constructions.The CBR values were very good in the range for both GBS and steel slag,thus repeated load triaxial test are done to determine the resilient modulus. k1-k3model was adopted and the regression coefficients were determined. Based on the results the pavement design is done using KENPAVE software. An exercise has been performed to determine the quantity of the conventional material that could be saved, considering the type and size of the pavement. For the aggregate sized steel slag, the tests were done to find the suitability of the material for various applications like, as railway ballast, concrete aggregate, gabion and rip rap stones. And the tests result shows the material to be suitable for these applications and is expected to perform well. Study on morphological parameters reveals that the size and gradation of any material plays an important role in its mechanical behavior, however in the case of slags, this could be tailor made by using appropriate crushers, as per the requirements.
36

Estudo das propriedades mec?nicas de biocomp?sitos de polipropileno refor?ados com fibras naturais

Bispo, Sistanley Jones Lima 20 June 2011 (has links)
Made available in DSpace on 2014-12-17T14:58:07Z (GMT). No. of bitstreams: 1 SistanleyJLB_DISSERT.pdf: 3362424 bytes, checksum: 30d67bc0b13dba47c7002133ab1bb63d (MD5) Previous issue date: 2011-06-20 / This research presents an approach to the addition of curau? fibers and licuri fibers in a polypropylene resin matrix, such as an alternative proposal to reinforce the polymeric composites. Fiber content of 0 %, 5 %, 10 %, and 20% were analyzed for verification of their mechanical properties comparing them, inclusive with the properties of polypropylene. The grainulated biocomposites had been prepared in an extrusora. The test bodies had been molded by injection and submitted to the mechanical essays uniaxial traction, flexion on three points, impact, in addition to thermal tests (HDT). These biocomposites had been also subjected the essay physicist-chemistry index of fluidity (IF). It was observed that the biocomposites of PP with 20% curau?, obtained bigger increase in the modulus of elasticity and a bigger reduction in the resistance to the impact. In the mechanical behavior, for all the biocomposites, these were increases in values of the limit of drainage and tension of rupture, when tested by uniaxial traction, as they added the fibers. Another important point was the increase of the resistance the flexion. It was also noted that the addition of fibers reduced the thermal degradation of the mixture natural fibers / polypropylene. / Esta pesquisa apresenta uma abordagem da adi??o de fibras de licuri e curau? em uma matriz de resina de polipropileno, essa como uma proposta alternativa de refor?o aos comp?sitos polim?ricos. Teores de fibras de 0 %, 5 %, 10 %, e 20 % foram analisados para verifica??o de suas propriedades mec?nicas comparando-as, inclusive com as propriedades do polipropileno. Os biocomp?sitos granulados foram preparados em uma extrusora. Os corpos de prova foram moldados por inje??o e submetidos aos ensaios mec?nicos de tra??o uniaxial, flex?o em tr?s pontos, impacto, al?m de ensaios t?rmicos (HDT). Estes biocomp?sitos tamb?m foram submetidos a ensaio f?sico-qu?mico de ?ndice de fluidez (IF). Observou-se que os biocomp?sitos de PP com 20% curau? obteve maior aumento no m?dulo de elasticidade, e uma maior diminui??o na resist?ncia ao impacto. No comportamento mec?nico, para todos os biocomp?sitos, houve acr?scimos nos valores do limite de escoamento e tens?o de ruptura quando ensaiados por tra??o uniaxial, ? medida que se adicionavam as fibras. Outro ponto importante foi o aumento da resist?ncia ? flex?o. Verificou-se tamb?m que a adi??o de fibras reduziu a degrada??o t?rmica da mistura fibras naturais / polipropileno.
37

Modelagem e simulação de sistema de embalagem e pesagem de material particulado em pó. / Modeling and simulation of a packaging and weighing system of granulated powders.

Rafael Couto Rodrigues de Oliveira 08 August 2014 (has links)
Esse trabalho é dedicado ao desenvolvimento de um simulador para sistema de pesagem e embalagem de produto em pó granulado. Tal simulador reproduz a variabilidade de peso dos cartuchos observados em um sistema de embalagem real. Para esse desenvolvimento foram aplicadas técnicas de Identificação de Sistemas para obter o modelo determinístico do processo e conceitos de Processos Estocásticos para reproduzir as perturbações. O simulador tem como objetivo a avaliação de propostas de melhorias nesse sistema de pesagem, visando reduzir o sobrepeso médio e a quantidade de cartuchos rejeitados por subpeso, denominados de scraps, diminuindo consequentemente as perdas monetárias do processo industrial de embalagem de produtos granulados, com grande potencial de reaplicação para outros tipos de produtos industrializados e sistemas de pesagem. O desempenho do simulador é muito bom, uma vez que as oscilações observadas nos pesos dos cartuchos, devido à variação de densidade, são bem reproduzidas. Portanto as principais contribuições desse trabalho são: 1) o uso de uma abordagem estatística e inovadora para modelar as perturbações, evitando o estudo profundo de suas causas, alcançando um modelo preciso, que simula resultados de sobrepeso e número de cartuchos rejeitados bem próximo da realidade; 2) identificação e quantificação de melhorias no sistema de pesagem e embalagem, sem a necessidade de altos investimentos, dando a opção de decisão de quais melhorias realmente serão implementadas; 3) sobrepeso e scrap normalmente estão entre as três principais perdas monetárias das indústrias que produzem produtos embalados por peso e esse simulador representa uma forma de redução significativa dessas perdas, trazendo uma grande vantagem competitiva em um mercado cada vez mais acirrado. / This work describes the development of a simulator for a packing and weighing system of granulated powder. This simulator reproduces the weight variability of observed cartons in a real packing system. In this development, System Identification techniques were used to obtain the deterministic part of the model and Stochastic Processes to reproduce disturbances. Its objective is to evaluate proposed improvements in the packing and weighing system, aiming at reducing the overweight average and the quantity of rejected cartons by underweight, denominated scraps, cutting down consequently the monetary losses of the granulated product packing process in the industry, with great reapplication potential to other kind of industry products and weighing systems. The simulator performance is very satisfactory, once the oscillations observed in the carton weights, due to powder density variability, are well reproduced. Hence, the main contributions of this work are: 1) use of a statistical and innovative approach to model the disturbances, avoiding a deep study of their causes, achieving a model that provided precise simulated overpacking and scrap results when compared to reality; 2) identification and quantification improvements of the weighing and packing system, with no large investment, giving the option of decision of which improvement will be actually implemented; 3) overweight and scrap are among the three main monetary losses in the industries that make products packed in weight and so this simulator of a packing and weighing system of granulated powder represents a way of reducing significantly these losses, bringing a big competitive advantage in a demanding market.
38

Avaliação da secagem de metformina 850mg em leito fluidizado industrial / Evaluation of drying of metformin 850mg in industrial fluidized bed

Souza, Jonas Laurentino de 24 February 2012 (has links)
Made available in DSpace on 2017-07-10T18:08:00Z (GMT). No. of bitstreams: 1 Jonas Laurentino de Souza.pdf: 1900199 bytes, checksum: 3994bd57ce92b5d78685371435d4291e (MD5) Previous issue date: 2012-02-24 / The oral administration of drugs for systemic effects is the most common way used in medical treatment. Among these, drugs as tablets are the most used. The granulation is a process that seeks to improve the transportation of powder in the compacting machine by the agglomeration of particles. The fluidized bed drying added to "spray dryer" technique is commonly used to form granules that reaches the required characteristics of a uniform grain, with strict control of final humidity of the granules and relatively short process when compared to other techniques for drugs production. Metformin is a drug displayed as hydrochloride and orally administered as coated tablets. It is indicated for the treatment of type 2 Diabetes mellitus. In order to improve productivity in an industrial fluidized bed used in the granulation and drying of Metformin, it is necessary to evaluate the effects of operation conditions used in the process, as particulate material and in the production process. For that purpose, it was performed the study of fluiddynamic granulation and drying of Metformin in fluidized bed in order to investigate the minimum fluidization velocity for the process of this drug. The influence of temperature and speed of drying air in processing time of the formula, and the average particle size were also evaluated. The experiments were elaborated based on the Evolutionary Operation Theory, proposed by Box (1957). It performed the shaping at drying stage. With these experiments was possible to reduce to zero the reworks of batches caused by the formation of preferential channels, which could occur deposition polymer solution on the particulate material. It was also possible to reduce the average processing time in 8 minutes, adding greater productivity and savings for the company where the work was developed. The results achieved, besides the gain in productivity, guide to where efforts should be directed to continue improving productivity, providing a practical methodology for applying the technique that can be applied in the production of other drugs that use the granulation process in fluidized bed. / A administração de fármacos para efeitos sistêmicos por via oral é a forma mais comum dentre os medicamentos. Dentre estes, os medicamentos na forma de comprimidos são os mais empregados. A granulação é um processo que visa melhorar o transporte do pó na máquina compressora por meio da aglomeração de partículas. A secagem em leito fluidizado acoplado à técnica de spray dryer é a técnica comumente empregada para a formação de grânulos que atendam as características necessárias de granulometria uniforme, com controle rigoroso da umidade final do granulado e tempo relativamente curto de processo quando comparado a outras técnicas para produção de medicamentos. A metformina é um fármaco, apresentado na forma de cloridrato, e administrado como comprimidos revestidos por via oral. É indicado no tratamento de diabetes, mais especificamente diabetes mellitus tipo 2. Com o objetivo de aprimorar a produtividade em um leito fluidizado industrial utilizado na granulação e secagem de metformina, faz-se necessário avaliar os efeitos das condições operacionais utilizadas no processo referentes a qualidade material particulado e o processo de produção propriamente dito. Para tanto, realizou-se o estudo fluidodinâmico da granulação e secagem de metformina em leito fluidizado investigando assim a velocidade mínima de fluidização para o processamento deste fármaco. A influência da temperatura e da velocidade do ar de secagem no tempo de processamento da fórmula e no tamanho médio da partícula também foram avaliados. Os experimentos foram elaborados a partir da teoria da Operação Evolutiva, proposta por Box (1957). A modelagem da etapa de secagem também foi realizada. Por meio dos experimentos realizados conseguiu-se reduzir a zero os reprocessos de bateladas por formação de canais preferenciais, onde poderia ocorrer deposição de solução polimérica sobre o material particulado. Foi possível também reduzir o tempo médio de processamento em 8 minutos, agregando maior produtividade e economia para a empresa na qual este trabalho foi desenvolvido. Os resultados obtidos mostram que houve ganhos em relação a produtividade, e norteiam para onde os esforços devem ser direcionados para continuidade do melhoramento de produtividade, fornecendo uma metodologia prática para aplicação da técnica que poderá ser aplicada na produção de outros fármacos que utilizam o processo de granulação por via úmida em leito fluidizado.
39

Redução de sulfato em biorreator operado em batelada e batelada alimentada seqüenciais contendo biomassa granulada com agitação mecânica e Draft-Tube / Sulfate reduction in bioreactor in sequencing batch and fed-batch containing granulated biomass with mechanical stirring and draft-tube

Gustavo Mockaitis 26 March 2008 (has links)
O presente projeto avaliou um reator anaeróbio operado em batelada e batelada alimentada seqüenciais (ASBR), em ciclos de 8 horas, utilizando biomassa granulada e agitação mecânica em um draft-tube, alimentado com água residuária sintética (500 mgDQO/L), contendo sulfato em diferentes relações DQO/[\'SO IND.4\' POT.2-\']. Em todos os ensaios o reator apresentou uma operação estável, produzindo alcalinidade e com concentração de ácidos voláteis totais em níveis adequados. Para os tempos de alimentação de 10 min, 3 h e 6 h, respectivamente, as eficiências de remoção de sulfato foram de 30, 72 e 72% nas operações nas quais o reator foi alimentado com uma relação DQO/[\'SO IND.4\'POT.2-\'] de 1,34. Nos ensaios nos quais o reator foi alimentado na relação DQO/[\'SO IND.4\'POT. 2-\'] de 0,67, as eficiências para a redução de sulfato foram de 25, 58 e 55%, respectivamente. Na operação com relação DQO/[\'SO IND.4\'POT.2-\'] de 0,34, as eficiências para redução de sulfato foram de 23, 37 e 27%, respectivamente. Desta maneira, pode-se concluir que as operações em batelada alimentada favoreceram a remoção de sulfato, enquanto foi observado que nas operações em batelada a remoção de matéria orgânica atingiu melhores eficiências. / This present work evaluate an anaerobic sequencing batch reactor (ASBR), fed in batch and fed-batch, and cycles of 8 hours, using granulated biomass and mechanical stirring in a draft-tube, fed with synthetic wastewater (500 mgCOD/L), enriched with sulfate in some COD/[\'SO IND.4\'POT.2-\'] relations. In all operations the reactor showed a stable operation, producing alkalinity and maintaining the volatile acids in adequate levels. Considering the fed periods of 10 min, 3 h and 6 h, respectively, the removal efficiencies of the sulfate was 30, 72 e 72%, in the operations when the reactor was fed with a COD/[\'SO IND.4\'POT.2-\'] relation of 1,34. In the essays when the reactor was fed in COD/[\'SO IND.4\'POT.2-\'] relation of 0,67, the efficiencies of the sulfate reduction was 25, 58 e 55%, respectively. When the reactor was operated with COD/[\'SO IND.4\'POT.2-\'] relation of 0,34, the efficiencies of sulfate reduction 23, 37 e 27%, respectively. Thus, is possible to conclude that the operations in fed-batch increased the efficiency of sulfate removal, at what time was observed that in batch operations the organic matter removal attained improved efficiencies.
40

Conception d'éco-liants et/ou éco-matériaux à partir de cendres volantes papetières et laitier moulu / Development of the eco-binders and/or eco-materials from paper fly ash and ground granulated blast-furnace slag

Seifi, Sahar 23 November 2018 (has links)
L'objet des travaux réalisés dans cette thèse concerne la mise en oeuvre d'un éco-liant à base de co-produits industriels : une cendre volante papetière et un laitier moulu, pour la fabrication de mortiers secs. Cet éco-liant a été élaboré pour remplacer partiellement le ciment comme constituant de matériaux traditionnels d'une part, et recycler en grande quantité l'un des deux déchets industriels, la cendre volante papetière tout en intégrant les notions d'économie circulaire et d'éco-conception d'autre part. La littérature fait état de nombreux travaux sur les différents types de cendres et de laitiers mettant en avant les caractéristiques, la minéralogie, la réactivité de ces cendres volantes papetières et des laitiers moulus. Ces deux coproduits avec environ 20% de SiO2 et 50% de CaO (% pondéraux), ont une composition chimique très proche de celle d'un ciment et développent des propriétés pouzzolaniques qui peuvent suppléer celles du ciment. Leur valorisation comme matériau liant est alors envisageable. Une complète connaissance des propriétés physico-chimiques, structurelles et minéralogiques de la cendre volante papetière et du laitier moulu a conduit à une étude exploratoire de formulations. Des mélanges à partir de 72% de cendres volantes papetières et de 28% de laitier moulu ont été étudiés en se référantà la formulation de base d'un mortier pour en optimiser la teneur en eau et le niveau d'énergie de compactage. Un matériel spécifique pour compacter les éprouvettes prismatiques de dimensions 4x4x16cm3 de mortier a été utilisé. L'effet de l'ajout de trois types d'activateurs i.e. chlorure de calciumCaCl2, métasilicate de sodium Na2O3Si et carbonate de sodium Na2CO3, et d'une faible quantité deciment i.e. 5% et 10% a été analysé mettant en relation la résistance mécanique et la microstructure desmélanges. Deux formulations optimales ont fait l'objet d'analyses relatives à la minéralogie, auxrésistances mécaniques à 2, 7 et 28 jours de cure, à la microstructure avec des images MEB,distributions des pores et à la durabilité. Compte-tenu des résultats satisfaisants obtenus, une approcheà l'échelle semi-industrielle de fabrication de blocs 15x15x15 cm3 à partir des deux formulationsretenues a été menée et discutée. Les premiers résultats montrent un grand intérêt pour la fabricationde pavés et de produits dérivés pour l'aménagement de zones piétonnes ou à circulation réduite. / The aim of this thesis is the development of an eco-binder based on industrial co-products : a wastepapery ash and a ground granulated blast-furnace slag, for the manufacture of dry mortars. On the one hand,this eco-binder was developed to replace partially cement as a constituent of traditional materials, andon the other hand to recycle in large quantities one of these two industrial wastes ; wastepaper fly ashwith considering all the notions of circular economy and eco-design. From literature, there are numerousand relevant research works on the different types of ash and slag, highlighting the characteristics, themineralogy, the reactivity of the wastepaper fly ash and ground granulated blast-furnace slags in details.These two co-products with about 20 wt.% SiO2 and 50 wt.% CaO have a chemical composition veryclose to that of a cement and develop pozzolanic properties that can replace those of cement. Theirvalorization as a binder material is then possible. A complete knowledge of the physicochemical, structuraland mineralogical properties of wastepaper fly ash and ground granulated blast-furnace slag led to anexploratory study of formulations for dry mortars. The mixtures containing 72 wt.% of wastepaper fly ashand 28 wt.% of ground granulated blast-furnace slag were investigated with reference to the formulationof a standard mortar to optimize the water content and compaction energy level. A specific equipment forcompacting prismatic specimens with dimensions 4x4x16 cm3 was used. The effect of adding three types ofactivators i.e. calcium chloride CaCl2, sodium metasilicate Na2O3Si and sodium carbonate Na2CO3, anda small amount of cement i.e. 5 wt.% and 10 wt.% was analyzed. The relation between mechanical strengthand the microstructure of the mixtures has been detailed and discussed. Two optimal formulations wereimplemented and, mineralogy, mechanical strength at 2, 7 and 28 days of curing, microstructure withSEM images, pore distributions and durability have been considered and analyzed. Taking into accountthe satisfactory results obtained, a semi-industrial approach to manufacture 15x15x15 cm3 blocks fromthe two selected formulations was conducted and discussed. The first results show a great interest in themanufacture of blocks of pavement and derived products for the construction of pedestrian or reducedtraffic areas.

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