In this thesis, characterization of two class F fly ashes (FA) from &Ccedil / atalagzi and Sug&ouml / z&uuml / thermal power plants were carried out and their utilization potentials in three different fields were examined. Characterization of sintered samples and determination of their utilization potentials in ceramic industry is the first research area in this thesis. For this purpose, the class F fly ash samples were first pressed into cylindrical specimen without the addition of any organic binders or inorganic additives, and then sintered to form ceramic materials. Effects of sintering temperature and time on sintering characteristics were investigated. In the experiments, the cylindrical specimens were first preheated to 300oC for 1 h to remove moisture and any other gases. The specimens were then fired at the temperatures of 1000oC, 1050oC, 1100oC and 1150oC for the sintering times of 0.5, 1.0, 1.5 and 2.0 hours. Heating rate of 10oC/min was kept constant throughout the experiments. Quality of sintered samples was evaluated in terms of ceramic specifications such as density, water absorption, porosity, shrinkage and splitting tensile strength. In addition, mineralogical and microstructural changes during sintering were determined with X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. According to literature data, better microstructure, the highest density and strength with the lowest porosity, water absorption and shrinkage values are the indications of the optimum sintering conditions. Based on these specifications, Sug&ouml / z&uuml / fly ash gave better results compared to &Ccedil / atalagzi fly ash, and the optimum conditions were achieved at the sintering temperature of 1150oC for the sintering time of 1.5 hours for both samples. Pozzolanic reactivity of the fly ashes and their utilization potentials in civil engineering applications were also examined in detail during this study. For this purpose, &Ccedil / atalagzi (CFA) and Sug&ouml / z&uuml / (SFA) fly ashes were first subjected to a specific hydraulic classification process developed at CAER (University of Kentucky, Center for Applied Energy Research) to recover ultrafine fly ash particles. The overflow products with average particle sizes of 5.2 &mu / m for CFA and 4.4 &mu / m for SFA were separated from the respective as-received samples with average particle sizes of 39 &mu / m and 21 &mu / m. After the classification stage, the pozzolanic activities of these ultrafine fly ash fractions (UFA) and as-received samples were examined by preparing a number of mortar (mixture of Portland cement (PC), FA or UFA as partial cement replacement, sand and water) and paste (mixture of PC, FA or UFA as partial cement replacement and water) specimens. Control samples containing only PC were also prepared and tested through the experiments for the comparison of the results. In the mortar experiments, three different PC replacement ratios by FA and UFA (10%, 20% and 30%) were used to examine the effects of FA and UFA samples on the fresh and hardened mortar properties such as water requirement, compressive strength, drying shrinkage and water expansion. These mortar tests indicated that ultrafine fractions of &Ccedil / atalagzi (CUFA) and Sug&ouml / z&uuml / (SUFA) fly ashes provided more than 10% reduction in water demand compared to the control sample for 30% PC replacement. The mortar cubes containing CUFA and SUFA samples exhibited also higher strength development rates after 14 days compared to the ones with as-received samples and PC only. At the end of the curing age of 112 days, both CUFA and SUFA provided more than 40% increase in compressive strength compared to the control sample for the PC replacement ratios higher than 20%. As a comparison, SUFA gave better results than CUFA in both water demand and compressive strength tests. The mortar bars prepared with the both FA and UFA samples exhibited very low shrinkage and expansion values. These values decreased generally with increasing PC replacement ratio especially after 14 days. In the paste experiments, thermogravimetric analyses (TGA) of the paste specimens prepared by using only with 20% PC replacement were carried out to determine pozzolanic reactivity of the samples. The difference between the remaining Ca(OH)2 (portlandite) contents in the paste specimens containing the fly ashes and the reference PC paste was used as a measure of pozzolanic reactivity. After 112 days, 68.56% and 62.68% Ca(OH)2 content of PC only pastes were obtained with the pastes containing CUFA and SUFA samples, respectively, corresponding to 11% and 13% more Ca(OH)2 consumptions in reference to the respective as-received samples. X-ray diffraction (XRD) analyses were also performed for comparison of main portlandite peak intensities in the paste specimens containing FA or UFA with those in the PC only paste during cement hydration. According to these XRD analyses, portlandite content in PC/UFA pastes decreased significantly after 14 days compared to the PC only paste. All of these tests and analyses showed that a highly reactive lower cost pozzolan with very fine particle size and higher surface area compared to regular fly ash pozzolans can be produced from both &Ccedil / atalagzi and Sug&ouml / z&uuml / fly ashes using a relatively simple hydraulic classification technology. Cenosphere recovery potentials from &Ccedil / atalagzi and Sug&ouml / z&uuml / fly ashes were also studied in this thesis. Determination of cenosphere content was done under optical microscope by particle counting on the basis of point and area. Based on the point-counting data, CFA and SFA samples originally contain 11.30% and 4.50% cenospheres, respectively. Variations of cenosphere contents in the fly ash samples were examined by using float-sink, screening and air classification tests. The results pointed out that cenosphere contents decreased with decreasing size and increasing density for both samples. According to the float-sink tests, &Ccedil / atalagzi fly ash has much more floating products and more cenospheres than Sug&ouml / z&uuml / fly ash for the same density interval. Based on the air classification results, cenospheres were concentrated in the underflow products, and cenosphere contents increased with increasing air pressure and decreasing motor speed for both samples. The most efficient cenosphere separation technique among the examined methods was screening. Cenosphere contents of CFA and SFA increased to 21.65% and 11.83%, respectively by only using simple screening through 38 &mu / m.

Roller Compacted Concrete (RCC) is new technology gaining popularity in the recent years due to its low cost, rapid construction, and using opportunity of by-products. RCC is widely used in the world. However, the use of RCC has been restricted to construction of few cofferdams, and limited to local use in dam construction up to date. In this thesis, two types of cement, two types of natural pozzolan, aggregates with varying gradations, and a type of water reducing chemical admixture were used. Prior to carrying out the tests, the chemical and physical properties of materials were determined. Additionally, steam curing was applied to the test specimens in order to get long term compressive strength at early ages. Differences between steam cured specimens and normal cured specimens have been discussed in the discussion part. In the study, the results indicate that usage of water reducing chemical admixture improves compressive strength of RCC. Moreover, it is revealed that usage of fine material is essential to obtain desired results since the amount of cementitious materials is considerably low in RCC. Steam curing is known as its property of providing long term compressive strength at early ages. It was observed that application of steam curing in CEM I type cement used RCC mixtures generated expected results. However, in CEM IV type cement used RCC mixtures compressive strength results did not behave in the same manner.

Perlite is a volcanic mineral. The latest investigations on ground perlite showed that it is suitable for pozzolanic usage. Thus, it is of vital importance especially for countries rich in perlite such as Turkey. The aim of this study is to investigate the advantages and problems associated with using perlite in concrete and to identify accurate methods and amounts of use for producing durable cementitious mixtures. Within the scope of this study, the alkali-silica reactivity of perlite containing cementitious mixtures were compared using four different methods. Expansion mechanism of the mixtures were tried to be understood by measuring the alkalinity of bath waters. In order to cope with early strength decreases caused by perlite addition, activation of the mixtures by chemical and thermal methods were attempted. It was found that chloride containing chemicals are very effective at later ages and sodium containing chemicals are more effective at early ages. Sodiumhydroxide addition to the perlite containing mixtures was found to be detrimental to both the initial and late-age strengths of mortars. It was concluded that perlite addition generally results in a decrease in alkali-silica expansions. However, the expansion of concrete samples should be investigated comprehensively. Thermal curing at high temperatures resulted in a rapid increase at 1-day strengths, however, for better ultimate strengths lower thermal treatments or no-thermal curing were found to be more effective. Compared to the traditional portland cement concretes, high-volume ground perlite concretes have environmental and economical advantages.

This thesis describes improvements on newly-discovered high-strength pozzolan-based materials fabricated via a low-cost chemical reaction that takes place between 90 and 115 ℃ for 3 to 24 hours. The reported results focus on pozzolan constituents acquired from Coal Combustion Products (CCPs) such as cenospheres, fly ash C and F, as well as bottom ash. The thesis reports on various types of these materials with specific gravity ranging from 0.5 to 1.6; compressive strength ranging from 300 to 3600 psi, and compressive modulus ranging from 50 to 240 ksi. In addition to their good mechanical properties under compression that are attractive for the building and construction industries, the materials further exhibit great potential for applications as energy absorption cores in sandwich construction that could extend their value in other industries including the automotive and aerospace industries. For example, the load-displacement curve exhibits a short elastic zone followed by a long load-plateau; while the materials crush through a controlled vertical cracking process. Additionally, an attempt was made to further decrease the manufacturing cost of the material by investigating incorporation of chemicals that accelerates dehydration of the mixture. One such successful chemical reported in this thesis is aluminum phosphate; while it is not conclusive how the chemical improves any major property.

Orientador: Jorge Luís Akasaki / Banca: Marco Antonio Morais Alcantara / Banca: Antonio Ludovico Beraldo / Resumo: A presente pesquisa contribui para a utilização de cinza de casca de arroz (CCA) na construção civil abordando dois aspectos importantes ainda em discussão na literatura. O primeiro aspecto compreende uma análise da influência que a forma de plantio, clima, solo, cultivares e fonte/quantidade de fertilizantes à base de nitrogênio, utilizados na cultura do arroz, exercem na composição química e nas propriedades cristalográficas da CCA. O segundo aspecto foi aplicar em pastas, argamassas e concretos de alto desempenho uma CCA com baixo teor de carbono, de elevado caráter pozolânico, na condição natural (sem moagem), produzida de uma maneira simples e sem controle de temperatura. De acordo com os resultados obtidos neste trabalho, verifica-se a importância de efetuar ensaios rotineiros de análises químicas e de Difração de Raio-X para manter o controle de qualidade das CCAs produzidas, pois em situação de produção de CCA em larga escala, poderiam ser utilizadas cascas de diferentes origens. Neste trabalho, também ficou comprovada a viabilidade técnica e científica do método de produção de CCA utilizado. O método produz CCA que, dependendo da forma de amassamento dos compósitos, pode dispensar o emprego de moinhos para aumentar a finura e/ou reatividade de CCAs. / Abstract: This research contributes to the use of rice husk ash (RHA) in the civil building covering two important aspects that still under discussion in the literature. The first one includes an analysis of the influence that the form of planting, climate, soil, rice and source/amount of nitrogen-based fertilizers used in rice cultivation in performing crystallographic properties and chemical composition of the rice husk ash. The second one was to aplicate to the pastes, mortar and concrete of high performance a RHA with low carbon, high pozzolanic character, in the natural physical state (without grinding), produced in a simple way and without control of temperature. According to the results obtained in this research, it is important to do routine testing of chemical analysis and X-ray Diffraction to keep quality control of RHAs produced, because at industrial production in large scale it can be used husks of different origins. This research was also demonstrated the feasibility technical and scientific method of production of RHA used. The method produces RHA that depending on the form of production of the composite may eliminate the use of grinders to increase the fineness and/or reactivity of RHAs. / Mestre

Orientador: Jorge Luis Akasaki / Banca: Marco Antonio Moraes Alcantara / Banca: Antônio Alberto Nepomuceno / Resumo: O presente trabalho apresenta um método de produção de cinza de casca de arroz (CCA) altamente reativa e de coloração clara, bem como o seu comportamento em matrizes de cimento Portland com o intuito de avaliar a atividade pozolânica da CCA. O trabalho está dividido em quatro etapas, a saber: construção de um forno e produção da cinza de casca de arroz, caracterização físico-química da CCA, verificação da atividade pozolânica do material através de métodos instrumentais e, finalmente, ensaios mecânicos em argamassas de cimento Portland. O forno utilizado para a produção da cinza de casca de arroz não apresenta controle de temperatura e, o tempo de queima é bastante longo, aproximadamente 36 horas. Neste método obtém-se cerca de 1,5Kg de cinza por processo de queima. A cinza obtida apresenta uma coloração clara e o seu caráter amorfo foi determinado através de diferentes métodos: difração de Raio-X, determinação do teor de sílica amorfa, análise termogravimétrica, Microscopia Eletrônica de Varredura (MEV) e ensaios mecânicos em argamassas de cimento Portland. O programa experimental também abrange estudos de variação da finura da CCA e estudos com diferentes porcentagens, em substituição ao cimento Portland. Os resultados obtidos foram comparados... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This research show a method of production white amorphous Rice Husk Ash (RHA), therefore, the behaviour of RHA in Portland cement matrix to evaluate the pozzolanic activity of this material. The research can be shared in four steps, to know: construction of an oven and production of rice husk ash, physical-chemical analysis of the rice husk ash, evaluation of pozzolanic activity of the pozzolan though instrumental analysis and, finally, mechanical properties of Portland cement mortars. The oven used for production of rice husk ash didn't have a control of temperature and, the time of burning is so longer, approximately 36 hours. In this method is obtained for about 1,5Kg of ash. The obtained ash has white colour and its amorphous phase were determined though different methods: X-ray diffractometry, determination of amorphous silica, Termogravimetric Analysis (TA), scanning electron microscopy (SEM) and mechanical properties of Portland cement mortars. Besides that, the experimental procedure involves studies on fineness variation of rice husk ash and different degrees of Portland cement substitution. The obtained results were compared with silica fume, because this is the most similar pozzolanic material with rice husk ash. The RHA produced under this method can be used... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2015-05-08T15:00:05Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2912303 bytes, checksum: 1801a9b29f733961e785f9de516a1e30 (MD5) Previous issue date: 2010-03-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Oil well structures are built by placing a steel casing and by cementing the space (annulus) between the casing and rock formations throughout the geological layers of wellbores. The structural integrity of these systems resides on the cementing operation, which is designed to offer structural support as well as corrosion protection of the casing. It also promotes zonal isolation among rock formations throughout the wellbore, which not only helps to avoid losses in production, but also reduces potential environmental damage due to leakage of contaminated fluids. In order to achieve these objectives, a hydraulic seal between the casing and the cement and between the cement and the rock formations must be ensured, so that fluid channels in the cement sheath can be prevented. Although oil and gas companies have always been aspiring for perfect zonal isolation, the scope of existing zonal-isolation problems is enormous. Hence, a great number of researchers have been motivated to study and predict lost of zonal isolation, helping to reduce the magnitude of such complex problem. Most research focus on the improvement of the cement properties whereas least effort is given to interface related aspects. This is mostly given to the fact that such important zone is difficult to assess. Such difficulties are mainly associated to inherent anisotropies of Portland cement based materials. Interface related aspects of the cement hydration are strongly affected by the local chemistry of the components of the matrix. The effect of such complex microstructure on the engineering parameters must be carefully examined, so that evaluation of the structure integrity can be properly made via Non Destructive Testings. The aim of this work is to correlate the mechanical properties (destructive and non-destructive) with the microhardness of cement paste at early ages. The samples were cast using Early Strength Development Portland cement and three water to binder ratio (0.33, 0.44 and 0.55 by mass). Also, two sets of cement pastes were mixed with and without a ground redbrick waste pozzolan replacing cement (20% by mass). The test ages were 1, 3 and 7 days. The micro features of the early hydrated cement pastes were assessed by means of Scanning Electron Microscopy (Backscattered Electron Imaging Mode) and Vickers Microhardness. The data shows that the presence of the pozzolan affects the distribution of hydrated cement grains and the homogeneity of the cement matrix, yielding to different microfeatures, reflecting on the mechanical properties. The local chemistry prevails over the average properties of the cement paste, especially at the contact between steel and cement. / As estruturas de poços de petróleo são constituídas por tubulações metálicas revestidas com material cimentício as quais atravessam diversas formações geológicas. A integridade estrutural destes sistemas depende principalmente da integridade do material revestimento, que tem como funções oferecer suporte estrutural à tubulação metálica, além de protegê-la contra corrosão. Tal revestimento é ainda responsável por isolar as diferentes formações geológicas existentes ao longo do poço, objetivando não apenas evitar perdas na produção, mas também reduzir potenciais danos ambientais devidos a vazamentos de fluidos contaminantes. De modo a atingir estes objetivos, um perfeito isolamento hidráulico deve ser garantido tanto entre a tubulação metálica e o revestimento cimentício quanto entre este revestimento e as formações rochosas, de maneira que a migração de fluidos possa ser evitada. Embora as companhias de gás e petróleo venham buscando a obtenção de um perfeito isolamento hidráulico, a freqüência de ocorrência destes problemas é enorme em todo o mundo. Deste modo, grande número de pesquisas tem se voltado ao estudo e entendimento das causas associadas à quebra deste isolamento hidráulico, ajudando a reduzir a magnitude de tão complexo problema. A maioria destas pesquisas objetiva o aprimoramento das propriedades do revestimento propriamente dito, enquanto que um número bastante reduzido está associado a aspectos relacionados às interfaces destes sistemas. Tal particularidade deve-se em grande parte ao fato de que tão importante região possui grandes dificuldades de avaliação. Tais dificuldades estão associadas principalmente às anisotropias inerentes aos materiais à base de cimento Portland. Aspectos da interface relacionados à hidratação do cimento são fortemente afetados pela química local dos componentes da matriz cimentícia. O efeito desta complexa microestrutura nas propriedades de engenharia das estruturas deve ser cuidadosamente examinado, podendo a avaliação da de sua integridade ser apropriadamente efetuada mediante Testes Não Destrutivos. O objetivo deste trabalho é correlacionar propriedades mecânicas (obtidas mediante técnicas destrutivas e não-destrutivas) com a microdureza de pastas de cimento em pequenas idades. As amostras ensaiadas foram confeccionadas utilizando cimento Portland de Alta Resistência Inicial e três relações água/aglomerante (0.33, 0.44 e 0.55 em massa). Dois conjuntos de amostras foram preparados: com e sem substituição parcial do cimento (20% em massa) por pozolana constituída de resíduos de cerâmica vermelha moídos. As idades avaliadas foram 1, 3 e 7 dias. As características microestruturais e micromecânicas das pastas de cimento hidratadas foram acessadas mediante técnicas de Microscopia Eletrônica de Varredura (no modo retroespalhado) e Microdureza Vickers. Os resultados mostram que a presença da pozolana afeta a distribuição dos grãos de cimento hidratados e a homogeneidade da matriz cimentícia, modificando suas características microestruturais, refletindo nas propriedades mecânicas. A química local prevaleceu sobre as propriedades medias da pasta de cimento, especialmente no contato entre o cimento e a superfície metálica.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-22T13:13:31Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação - Emerson Silva - Versão definitava.pdf: 2135263 bytes, checksum: 0a3cbcc3e5c3ecb44715e0fbc253bd60 (MD5) / Made available in DSpace on 2016-07-22T13:13:31Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação - Emerson Silva - Versão definitava.pdf: 2135263 bytes, checksum: 0a3cbcc3e5c3ecb44715e0fbc253bd60 (MD5) Previous issue date: 2016-02-17 / Muitos estudos acerca do aproveitamento de resíduos e sua utilização em matrizes cimentícias têm sido desenvolvidos, na busca de um destino adequado, uma vez que a construção civil é um dos maiores consumidores de materiais naturais em seus processos e produtos. As cinzas agroindustriais ocupam lugar de destaque dentre os resíduos com possibilidades de aplicação por apresentarem propriedades pozolânicas, como por exemplo, cinzas volantes, sílica ativa entre outros, contribuindo para a redução do consumo de cimento Portland e sustentabilidade da indústria de materiais cimentícios. O bagaço da cana-de-açúcar é um dos subprodutos do processo de produção da cana-de-açúcar, sendo o Brasil o maior produtor mundial. Neste trabalho foram produzidas cinzas a partir do beneficiamento por queima controlada e moagem da cinza do bagaço de cana-de-açúcar (CBCA) coletada em uma usina do estado de Pernambuco para avaliar a sua aplicação como adição mineral em matrizes de base cimentícia. A cinza coletada foi submetida a um processo prévio de secagem em estufa e peneiramento para retirada de materiais contaminantes (folhas, pedras e outros). Parte do material passante não sofreu tratamento térmico, sendo denominada CAN, o restante foi dividido em quatros frações, cada fração submetida a uma temperatura de queima: 300°C, 400°C, 500°C e 600°C, sendo denominadas CB300, CB400, CB500 e CB600, respectivamente. Após a queima, cada cinza passou por um processo de peneiramento/moagem e foi submetida a análises de fluorescência de raios X, difração de raios X, massa específica real por picnometria a gás e área superficial específica por B.E.T (Brunauer-Emmett-Teller). A reatividade das cinzas foi avaliada por meio de medições de condutividade elétrica em solução saturada de Ca(OH)2/cinzas e o índice de atividade com cal (IAC), foi baseado na ABNT NBR 5751 (2012). Os resultados por condutividade elétrica indicam tendência de reatividade do material estudado, quando comparado a pozolana de referência - MTC. O IAC das amostras com CBCA mostraram resultados satisfatórios apenas para as cinzas moídas por 7 horas. A moagem mostrou ser de fundamental importância para o aumento do potencial pozolânico da CBCA. A temperatura de calcinação se mostrou relevante quando da aplicação de 500ºC, acima deste valor ocorreu o decréscimo dos índices de pozolanicidade. / Many studies about waste recovery and your use in cement matrices have been developed on the search for a appropriate destination, since the civic construction is one of the largest consumers of natural materials in their processes and products. The agroindustrial ashes occupy prominent place among the residues with application possibilities for presenting pozzolanic properties, such as fly ash, silica fume among others, contributing for the reduction of the consumption of cement Portland and sustainability of cementitious materials industry. The bagasse of the sugarcane is one of the byproducts of the production process of sugarcane, with Brazil being the world's largest producer. In this work were produced ashes from the beneficiation by controlled burning and grinding of ash from sugarcane bagasse (CBCA) collected in a mill of Pernambuco to evaluate your application as mineral addition in cement-based matrices. The collected ash was submitted to a previous drying process in a kiln and sieving for removing contaminant material (leaves, stones and other) part of the passing material did not suffer thermal treatment, called CAN, the remainder was divided into four portions, each portion submitted to a firing temperature: 300 ° C, 400 ° C, 500 ° C and 600 ° C, called CB300, CB400, CB500 and CB600, respectively. After burning, each ash passed through a process of sieving/milling and was submitted to X-ray fluorescence analysis, X-ray diffraction, real specific mass by gas pycnometry and specific surface area by BET (Brunauer-Emmett-Teller). The reactivity of the ash was evaluated by means of electrical conductivity measurements in saturated solution of Ca(OH)2 / ashes. The activity index with lime (AIL), based on the ABNT NBR 5751 (2012). The results by electrical conductivity indicates tendency of reactivity of the studied material, when compared to the pozzolan of reference - MTC. The AIL of de samples with CBCA showed satisfactory results just for milled ashes for 7 hours. The milling showed to be of fundamental importance for improve the pozzolanic potential of the CBCA. The temperature showed to be relevant whe the application of 500ºC, above this value occurred decrease of pozzolanicity index.

The diploma thesis deals with development and properties of historic mortars, evolves and optimizes recipe of historicizing universal mortar with mixture binder, which have been evolves in previous phase. Binder system is based on lime hydrate and metakaolin and is modified with fast-pacing gypsum. Thesis follow up technological properties of mixtures of historicizing mortars and modifies them for current construction industry. It also follows effect of modification to phase composition of binder system and eventually rise of AFt phases.

The subject of this thesis is selected parameters cement mortars with partial replacement of Portland cement diatomaceous earth. This work provides information on the basic properties of diatomaceous earth and its deposits with a focus on deposit in Borovany. From the properties is very important pozzolanic activity due to the high content of amorphous silica of this soil. The main use of diatomaceous earth is in the area filtration and is used widely as a nutritional supplement. In the building industry, diatomite can be applied as an admixture to mortar and concrete, where it can, with its abilities, improve some physical mechanical properties. In the experimental part was diatomaceous earth, in its raw and calcined form, tested as admixture for cement pastes and mortars. The main criterion for evaluating these composites was bulk density, flexural and compressive strength. It was also investigated mineralogical composition, microstructure, freeze–thaw resistance and sulfate resistance.