O uso de fibras vegetais e de cimentos alternativos – ambos provenientes de resíduos, é tido como boa opção na busca por novos fibrocimentos. Entretanto, a maioria das pesquisas desenvolvida nos últimos anos tem apresentado resultados desanimadores no que se refere à durabilidade do material. Além disso, os métodos para avaliação do desempenho ao longo do tempo de materiais reforçados com fibras sensíveis a álcalis ainda não estão bem estabelecidos. O trabalho avaliou o comportamento de compósitos produzidos com cimento de escória de alto-forno reforçados com fibras de celulose, moldados através de adaptações dos processos industriais usados em todo mundo pelas empresas de fibrocimento. Em seguida, a durabilidade das formulações foi avaliada através de ensaios de envelhecimento, os quais se basearam na simulação dos principais agentes e mecanismos de degradação atuantes no material. O desempenho físico e mecânico dos compósitos foi avaliado através da análise de propriedades pré-estabelecidas, consideradas importantes no emprego material como componente construtivo. A análise dos resultados confirmou a eficiência da incorporação da celulose nas propriedades mecânicas do compósito. A durabilidade do material foi diferente para as matrizes empregadas. As matrizes ativadas com gipsita e cal hidratada (EGCH) foram menos agressivas às fibras, entretanto apresentaram problemas de hidratação às primeiras idades e perda de resistência devido à carbonatação. A matriz ECP, mais alcalina, apresentou resultados superiores de resistência mecânica nas primeiras idades. Ela decompôs as fibras e reduziu as propriedades mecânicas durante o envelhecimento. A carbonatação reduziu o ataque alcalino às fibras nestas matrizes, estabilizando a resistência mecânica e a perda de tenacidade não foi tão acentuada. A metodologia de envelhecimento acelerado que combinou ciclos de molhagem e secagem à carbonatação se mostrou eficiente na simulação do envelhecimento natural. / Vegetable fibers and alternative cements from residues is a good option for replacement asbestos-cement. However, research development has presented no satisfactory results concerning material durability and methods of performance evaluation to reinforced materials with alcali sensitive fibers are not well developed. The objetives of this research are: a) evaluation of composites behavior produced with blast-furnace slag reinforced with residual cellulose fibers, which were moulded in adapted conventional industrial processes, common in fibercement companies around world and b) durability performance evaluation applying proposed aging tests. Aging tests were based on simulation of main agents and degradation mechanisms. Physical and mechanical behaviour of composites was evaluated considering important properties in building component uses. Cellulose fibers improved the mechanical properties of the composites. Durability presented different results for the two matrices. The matrices activated with gypsum and hidrated lime (EGCH) have been less aggressive than matrix activated with ordinary Portland cement (OPC) in relation to fibers. However, they presented problems concerning to the hydration at early dates and loss of resistance due to carbonation. Matrices activated with OPC presented better results of MOR at the early dates. In fact, they are more alkaline and they decomposed fibers and reduced the mechanical properties during the aging. The carbonation reduced the alkaline attack, stabilizing the MOR and reducing the loss of tenacity. The accelerated methods with carbonation were efficient in the simulation of the natural ageing.

In recent years, there has been a growing trend for the use of industrial by-products in the production of blended cements because of economical, environmental, ecological and diversified product quality reasons. Granulated blast furnace slag, a by-product of the transformation of iron ore into pig-iron in a blast furnace, is one of these materials which is used as a cementitious ingredient. The aim of this study is to investigate the properties of Portland slag cement (CEMII/B-S) by using separate grinding and intergrinding of granulated blast furnace slag and Portland cement clinker. For this purpose, granulated blast furnace slag was used as mineral admixture replacing 30% of the clinker. Clinker and granulated blast furnace slag were ground to four different Blaine fineness values of 3000 cm2/g, 3500 cm2/g, 4000 cm2/g and 4500 cm2/g by intergrinding and separate grinding in a laboratory ball mill. Then, eight Portland slag cement mixes and four Portland cement control mixes were prepared, in order to determine and compare 2-, 7-, 28-, and 90-day compressive and flexural strengths, normal consistencies and setting times. It was found that for the Blaine fineness values of 3000 cm2/g, 3500 cm2/g and 4000cm2/g, the 2-, 7-, 28-, and 90-day compressive strength of the interground Portland slag cements had higher values than the separately ground Portland slag cements. However, for the Blaine fineness values of 4500 cm2/g, separately ground Portland slag cement specimens had slightly higher 2-, 7-, 28-, and 90-day compressive strength values than the interground ones.

The purpose of this project was to produce a “greener” cement from granulated ground blast furnace slag (GGBS) using non-Portland cement activation. By eventually developing “greener” cement, the ultimate goal of this research project would be to reduce the amount of Portland cement used in concrete, therefore reducing the amount of carbon dioxide emitted into the atmosphere during cement production. This research studies the behavior of mineral binders that do not contain Portland cement but instead comprise GGBS activated by calcium compounds or fluidized bed combustion (FBC) bottom ash. The information described in this paper was collected from experiments including calorimetry, which is a measure of the release of heat from a particular reaction, the determination of activation energy of cement hydration, mechanical strength determination, and pH measurement and identification of crystalline phases using X-ray diffraction (XRD). The results indicated that it is possible to produce alkali-activated binders with incorporated slag, and bottom ash, which have mechanical properties similar to ordinary Portland cement (OPC). It was determined that the binder systems can incorporate up to 40% bottom ash without any major influence on binder quality. These are positive results in the search for “greener cement”.

Resumo: A escória de siderurgia é um dos resíduos gerados durante a produção de ferro-gusa. O Brasil é um dos maiores produtores de ferro-gusa e isso significa geração de aproximadamente dez milhões de toneladas por ano deste passivo ambiental. Entretanto, as escórias básicas de siderurgia podem ser usadas como corretivos de acidez do solo, fornecendo cálcio, magnésio e silício, sendo que o seu uso evita a extração de outros produtos da natureza, como o calcário, por exemplo. Os objetivos deste trabalho foram avaliar a influência das escórias de siderurgia no crescimento e nutrição do eucalipto na sua fase inicial (6 meses pós plantio) e nos atributos químicos do solo. O experimento foi conduzido em Latossolo e Neossolo Quartzarênico e foi analisado de duas formas: 1ª) avaliação do efeito da aplicação de doses crescentes de escória (doses proporcionais a zero; 300; 600; 1200 e 2400 kg/ha); e 2ª) comparação do tratamento equivalente a 2400 kg/ha de escória com testemunha absoluta, adubação química (somente NPK) e calcário. O delineamento experimental foi o de blocos inteiramente casualizados, com seis repetições. Foram realizadas análises químicas de solo aos três e aos seis meses após o início da condução do experimento. Avaliou-se mensalmente a altura e o diâmetro das plantas e, ao encerramento, quantificou-se massa verde e massa seca de folhas, galhos, tronco e raízes, área foliar, teores de macro e micronutrientes e silício nas folhas, galhos, tronco e raízes. Os dados foram analisados estatisticamente com o auxílio do programa SISVAR.2 Os resultados indicaram que, após três meses, a aplicação de 2400 kg/ha de escória proporcionou aumento do pH e V% do solo e redução da acidez potencial em ambos os solos. Após seis meses do plantio, os valores de pH foram semelhantes quando se comparou a dose de 2400 kg/ha com o calcário... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Blast furnace slag is one of residues generated during cast-iron production. Brazil is one of the largest producers of cast-iron. This means the generation of approximately ten million tonnes per year of environmental liabilities. However, slag can be used as soil pH-correcting material supplying calcium, magnesium and silicon, and that its use prevents the extraction of other products of nature, such as limestone, for example. The objectives of this study were to evaluate the influence of blast furnace slags on growth and nutrition of eucalyptus in its initial phase (6 months after planting) and chemical soil attributes. The experiment was conducted in Oxisol and a Typic Quartzipsamment and was analyzed in two ways: 1st) evaluation of the effect of application of increasing slag doses (rates proportional to zero, 300, 600; 1200 and 2400 kg / ha), and 2nd) comparison of a treatment equivalent to 2400 kg / ha of slag against an absolute control, chemical fertilization (NPK only) and limestone. The experimental design consisted of completely randomized blocks with six repetitions. Soil chemical analyses were performed three and six months after installation of the experiment. It was evaluated monthly height and diameter of the plants and the closure, is quantified green and dry mass of leaves, branches, trunk and roots, leaf area; macronutrient, micronutrient, and silicon in the leaves, branches, trunk and roots . The data were analyzed statistically using the SISVAR software program. The results indicated that, after three months, the application of 2400 kg / ha of slag increased soil pH and V%, and decreased potential acidity in both soils. Six months after planting, pH values were similar when the 2,400 kg / ha dose was compared with the dose of limestone. Increased slag doses provided increased green and dry mass production of leaves, leaf area, and dry mass of branches, increased leaf... (Complete abstract click electronic acess below) / Orientador: Iraê Amaral Guerrini / Coorientador: Dirceu Maximino Fernandes / Banca: Roberto Lyra Villas Bôas / Banca: Lísias Coelho / Mestre

A presente pesquisa tem como objetivo desenvolver um novo elemento de cobertura, compatível com o meio ambiente: telhas de cimento alternativo reforçado com fibras celulósicas. Para tanto, foram utilizadas matérias-primas consideradas resíduos industriais (cimento de escória de alto-forno e rejeito de polpa de celulose de eucalipto) para obtenção de pastas cimentícias reforçadas. Os compósitos foram produzidos por dispersão prévia das fibras em água, mistura do compósito em argamassadeira convencional, adensamento por vibração, moldagem em fôrmas, seguida de cura úmida. Foram moldadas placas planas de diferentes formulações de matrizes cimentícias, com as matérias-primas alternativas disponíveis. Com base nos melhores resultados dessa fase preliminar, foram produzidas duas séries de telhas tipo romana \"capa canal\". Foram avaliados o desempenho físico-mecânico, os custos de produção e o comportamento térmico das telhas. Os resultados revelaram a potencialidade dos compósitos obtidos na produção de fibrocimentos alternativos, por meio de técnicas simples e de baixo consumo de energia, direcionados à autoconstrução urbana e rural de baixo custo. / The objective of this study was to develop a new roofing material that would be compatible with the environment: roofing tiles made of alternative cement reinforced with cellulose fibers. Industrial waste materials were used as raw materials (blast furnace slag cement and waste eucalyptus cellulose pulp) to obtain reinforced cement pastes. The composites were produced by previously dispersing the fibers in water, mixing the composite in a conventional cement-mixer, compaction by vibration, shaping them in molds, followed by moist curing. Flat sheets were molded using different formulations of cement matrixes with the alternative raw materials avaiable. Based on the best results from this preliminary phase, two series of Roman tiles for roofing were produced. The physical and mechanical performance, the cost of production, and the thermal behavior of the tiles were evaluated. The results revealed the potential of composites made of alternative fiber-cements, using simple techniques and with low energy consumption, in urban and rural areas for low-cost self-construction.

O uso de fibras vegetais e de cimentos alternativos – ambos provenientes de resíduos, é tido como boa opção na busca por novos fibrocimentos. Entretanto, a maioria das pesquisas desenvolvida nos últimos anos tem apresentado resultados desanimadores no que se refere à durabilidade do material. Além disso, os métodos para avaliação do desempenho ao longo do tempo de materiais reforçados com fibras sensíveis a álcalis ainda não estão bem estabelecidos. O trabalho avaliou o comportamento de compósitos produzidos com cimento de escória de alto-forno reforçados com fibras de celulose, moldados através de adaptações dos processos industriais usados em todo mundo pelas empresas de fibrocimento. Em seguida, a durabilidade das formulações foi avaliada através de ensaios de envelhecimento, os quais se basearam na simulação dos principais agentes e mecanismos de degradação atuantes no material. O desempenho físico e mecânico dos compósitos foi avaliado através da análise de propriedades pré-estabelecidas, consideradas importantes no emprego material como componente construtivo. A análise dos resultados confirmou a eficiência da incorporação da celulose nas propriedades mecânicas do compósito. A durabilidade do material foi diferente para as matrizes empregadas. As matrizes ativadas com gipsita e cal hidratada (EGCH) foram menos agressivas às fibras, entretanto apresentaram problemas de hidratação às primeiras idades e perda de resistência devido à carbonatação. A matriz ECP, mais alcalina, apresentou resultados superiores de resistência mecânica nas primeiras idades. Ela decompôs as fibras e reduziu as propriedades mecânicas durante o envelhecimento. A carbonatação reduziu o ataque alcalino às fibras nestas matrizes, estabilizando a resistência mecânica e a perda de tenacidade não foi tão acentuada. A metodologia de envelhecimento acelerado que combinou ciclos de molhagem e secagem à carbonatação se mostrou eficiente na simulação do envelhecimento natural. / Vegetable fibers and alternative cements from residues is a good option for replacement asbestos-cement. However, research development has presented no satisfactory results concerning material durability and methods of performance evaluation to reinforced materials with alcali sensitive fibers are not well developed. The objetives of this research are: a) evaluation of composites behavior produced with blast-furnace slag reinforced with residual cellulose fibers, which were moulded in adapted conventional industrial processes, common in fibercement companies around world and b) durability performance evaluation applying proposed aging tests. Aging tests were based on simulation of main agents and degradation mechanisms. Physical and mechanical behaviour of composites was evaluated considering important properties in building component uses. Cellulose fibers improved the mechanical properties of the composites. Durability presented different results for the two matrices. The matrices activated with gypsum and hidrated lime (EGCH) have been less aggressive than matrix activated with ordinary Portland cement (OPC) in relation to fibers. However, they presented problems concerning to the hydration at early dates and loss of resistance due to carbonation. Matrices activated with OPC presented better results of MOR at the early dates. In fact, they are more alkaline and they decomposed fibers and reduced the mechanical properties during the aging. The carbonation reduced the alkaline attack, stabilizing the MOR and reducing the loss of tenacity. The accelerated methods with carbonation were efficient in the simulation of the natural ageing.

This thesis deals with development of shrinkage reducing admixtures designed for alkali activated materials based on blast furnace slag. The main task of this work is to select the most suitable shrinkage reducing admixture based on experiments, in which can be observed minimal shrinkage and at the same time it will not adversely affect the properties of alkali activated blast furnace slag. In the experimental part of the work, test beams containing shrinkage reducing admixtures were prepared, in which the shrinkage and loss of weight were measured. Moreover, the mechanical properties of individual beams, such as tensile strength and compressive strength, were measured. Next, the surface tension of individual shrinkage reducing admixtures was measured in a mixture with pore solution. The hydration process of alkali activated materials under the action of reducing shrinkage admixtures was monitored by calorimetric analysis. The microstructure of the prepared samples was observed by scanning electron microscopy.

This diploma thesis is focused on methods of using cement kiln by-pass dust in building materials technology. By-pass dust was treated to remove chlorides and could then be used as other constituent to various types of cements in the amount of 0–5 wt. % according to ČSN EN 197-1. The properties of dusts before and after chloride removal were examined and after incorporating modified by-pass dust into the cement, the properties of fresh and hardened cement pastes and mortars were studied. It was found that modified by-pass dust after incorporation into cement fulfill requirements of ČSN EN 197-1.

Alkali-activated materials (AAM) are construction materials with great potential, especially for their environmental friendliness, but also due to their mechanical properties. Therefore, it is appropriate to pay further attention to these binders. This diploma thesis deals with monitoring the effectiveness of plasticizers in connection with the surface chemistry of the alkali-activated slag system. Sodium hydroxide and sodium water glass were used as alkaline activators for the preparation of alkali-activated blast furnace slag-based systems. To study the effectiveness of the lignosulfonate plasticizer, yield stress, heat flow, adsorption and zeta potential were monitored depending on the amount and time that the plasticizer was added to the system. The results show that the type of activator used in the mixtures plays an important role. NaOH-activated samples revealed the best efficiency of lignosulfonate plasticizers. A key factor in studying the behavior of the studied mixtures was the measurement of the zeta potential, which provided insight into the surface charge of blast furnace slag particles related to the ability of lignosulfonate to adsorb on grains of alkali-activated slag.

Alkali activated materials could be suitable alternative to construction materials based on ordinary Portland cement (OPC). Therefore, it is advisable to pursue these binders further on. Aim of this thesis is to clarify the effect of lignosulfonate-based plasticizer and polycarboxylate-based superplasticizer on the behaviour and nature of alkali activated materials. For the purposes of studying the efficiency of plasticizing additives, the change of workability of alkali activated blast furnace slag in dependence on time, effect of additives on mechanical properties as well as, with usage of isothermal calorimetry, their impact on kinetics of solidification and hardening had been observed. The stability of the plasticizing admixtures in a high alkaline environment such as water glass and sodium hydroxide had been studied using infrared spectrometry. As a last step, X-ray photoelectron spectroscopy (XPS) had been used while clarifying the chemical changes in the structure of plasticizing additives after adsorption to blast furnace slag.