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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.
11

Shale Gas & Oil : a nova dinâmica energética mundial e as perspectivas para o Brasil

Cambi, Rui Cesar January 2017 (has links)
Orientador: Prof. Dr. Igor Fuser / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, 2017. / A premente necessidade de energia é cada vez mais atual na sociedade contemporânea. O seu uso está correlacionado aos costumes, estágio de desenvolvimento e ao grau de industrialização do país. A busca por novos recursos energéticos é questão primordial para o bem-estar das pessoas e para a expansão econômica dos países. A descoberta de importantes recursos energéticos, denominados hidrocarbonetos não convencionais tais como: óleo pesado e ultrapesado, areias betuminosas, óleo encontrado em águas profundas e ultraprofundas como o pré-sal e o shale gas & oil que está disseminado de forma homogênea pelo mundo todo, vem chamando a atenção de vários países. Os EUA, um dos maiores importadores de petróleo e gás do mundo, são portadores de vastas reservas de shale gas & oil e possuem conhecimento geológico e tecnologia adequada. Isso tornou o país o precursor da exploração desse energético no mundo. A produção dos Estados Unidos vem crescendo significativamente, reduzindo sua dependência de petróleo e gás importado, provocando abundância no mercado global, o que resulta em queda de preço do petróleo e gás, alterando a geopolítica da energia mundial. O Brasil, no contexto mundial, possui reservas expressivas de não convencionais, sendo a 10ª maior reserva do mundo. É crescente a necessidade de energia pela sociedade brasileira e o país vem demonstrando interesse em explorar esses energéticos. Esta dissertação tem como objetivo analisar as perspectivas mundiais de exploração desses hidrocarbonetos não convencionais à luz da experiência dos EUA, analisando o panorama brasileiro para futuras explorações. Este estudo mostrou como resultado que o Brasil terá dificuldades de replicar a exploração do shale gas & oil, como ocorreu nos EUA. / The pressing need for energy is increasingly present in contemporary society. Energy consumption is correlated with their customs, the stage of development and the degree of industrialization of the country. The search for new energy resources is a key issue for people's well-being and for the economic expansion of countries. The discovery of important energy resources, called unconventional hydrocarbons shale gas & oil, spread democratically around the world, has drawn the attention of several countries. The US, one of the largest importers of oil and gas in the world, carry vast reserves of shale gas & oil and has geological knowledge and appropriate technology. This made the country the precursor of the exploitation of this energy in the world. US production has been growing significantly, reducing its dependence on imported oil and gas, sparking global market abundance, resulting in falling oil and gas prices, shifting global energy geopolitics. Brazil in the world context has significant reserves, being the 10th largest reserve in the world. There is a growing need for energy by Brazilian society. The country has been showing interest in exploiting these energy sources. The objective of this dissertation is to analyze the global prospects for exploration of these unconventional hydrocarbons in the light of the US experience, to evaluate possible interferences in the geopolitics of energy at global level, ascertaining socioeconomic and environmental issues, knowledge to support future development studies on Brazilian soil.
12

A New Method for History Matching and Forecasting Shale Gas/Oil Reservoir Production Performance with Dual and Triple Porosity Models

Samandarli, Orkhan 2011 August 1900 (has links)
Different methods have been proposed for history matching production of shale gas/oil wells which are drilled horizontally and usually hydraulically fractured with multiple stages. These methods are simulation, analytical models, and empirical equations. It has been well known that among the methods listed above, analytical models are more favorable in application to field data for two reasons. First, analytical solutions are faster than simulation, and second, they are more rigorous than empirical equations. Production behavior of horizontally drilled shale gas/oil wells has never been completely matched with the models which are described in this thesis. For shale gas wells, correction due to adsorption is explained with derived equations. The algorithm which is used for history matching and forecasting is explained in detail with a computer program as an implementation of it that is written in Excel's VBA. As an objective of this research, robust method is presented with a computer program which is applied to field data. The method presented in this thesis is applied to analyze the production performance of gas wells from Barnett, Woodford, and Fayetteville shales. It is shown that the method works well to understand reservoir description and predict future performance of shale gas wells. Moreover, synthetic shale oil well also was used to validate application of the method to oil wells. Given the huge unconventional resource potential and increasing energy demand in the world, the method described in this thesis will be the "game changing" technology to understand the reservoir properties and make future predictions in short period of time.
13

Survival of the Unfit : Path Dependence and the Estonian Oil Shale Industry

Holmberg, Rurik January 2008 (has links)
Estonia is the only country in the world, which is totally dependent on oil shale in its energy system. Although this fossil fuel exists in enormous quantities around the world, it has so far not been utilized on a larger scale. The reasons for this have been both economic and, in recent times, ecological. It can therefore be argued that in most cases, oil shale represents an inferior solution compared to other energy sources. This work examines why a technology utilizing oil shale has developed in Estonia and why Estonia appears not to be in a position to switch to other energy sources. In this work it is claimed that oil shale actually has been an appropriate solution to short-term concerns, despite the fact that its long-term drawbacks have been identified. These circumstances led to path dependence. Once the technology was in place, it advanced along its learning curve producing a satisfactory outcome, but not an optimal one. However, this situation has been accepted due to the extremely turbulent institutional environment Estonia has undergone in the 20th century. In Sweden, a somewhat similar (but smaller) oil shale industry was shut down in the 1960s because of poor economic performance, but also because of the competition from other energy sources. Such competition did not take place in Estonia, in part due to the specific institutional set-up of the Soviet Union. This made it possible for the Estonian oil shale industry to develop further, causing the present lock-in. Today the existing infrastructure, the knowledge-base, and the particular socio-political circumstances of Estonia effectively prevent change. Furthermore, it is argued that because there was only little oil shale-related technology developed outside Estonia, most technology had to be developed domestically. This in turn has forced the Estonian oil shale industry to make several highly inconvenient alliances in order to gain room to manoeuvre. Partially as a result of this, there is today wide-spread scepticism towards the industry, but no exit in sight in the foreseeable future. One purpose of this work is to contribute to a broader understanding why human societies have become dependent on fossil fuels and to extend our knowledge on where to search for an exit.
14

World oil supply and unconventional resources : Bottom-up perspectives on tight oil production

Wachtmeister, Henrik January 2018 (has links)
Oil is the world’s largest primary energy source. It dominates the transportation sector which underpins the world economy. Yet, oil is a nonrenewable resource, destined not to last forever. In the mid-2000s global conventional oil production stagnated, leading to rising oil prices and fears of permanent oil scarcity. These fears, together with the high prices, receded with the unforeseen emergence of a new supply source: tight oil. This licentiate thesis investigates unconventional tight oil production and its impacts on world oil supply in terms of resource availability and oil market dynamics, and in turn briefly discusses some possible wider economic, political and environmental implications of these impacts. The thesis is based on three papers. The first investigates the usefulness of bottom-up modelling by a retrospective study of past oil projections. The second looks at how unconventional tight oil production can be modelled on the well level using decline curve analysis. The third derives typical production parameters for conventional offshore oil fields, a growing segment of conventional production and a useful comparison to tight oil. The results show that tight oil production has increased resource availability significantly, as well as introduced a fast responding marginal supply source operating on market principles rather than political ones. The emergence of tight oil production has altered OPEC’s strategic options and led to a period of lower and less volatile oil prices. However, this condition of world oil supply can only last as long as the unconventional resource base allows, and, at the same time, total fossil fuel consumption will have to fall to limit climate change. It is concluded that this breathing space with lower oil prices could be used as an opportunity to develop and implement policy for an efficient managed decline of global oil use in order to achieve the dual goals of increased human economic welfare and limited climate change, and in the process preempt any future oil supply shortage. Unconventional tight oil production can both help and hinder in this endeavor. Accurate models and analyses of oil production dynamics and impacts are therefore crucial when maneuvering towards this preferred future.
15

Ťažba z bridlicových ložísk v USA od 70. rokov 20. storočia k prelomu milénií: cesta k energetickej nezávislosti? / Shale Extraction in the U.S. from the 1970s to the Turn of the Millennium: The Path to Energy Independence?

Záhradníková, Lea January 2014 (has links)
Master's s thesis determines potential influence of "shale miracle" observed in the U.S. since the first decade of new millennium on energy independence which has been one of the U.S. policy priorities since the 1970s' oil shocks. Technological development and innovations supported by the government triggered an unexpected and in its way unique boom, which significantly strengthened the U.S. economy. The thesis examines impact of oil crises on the U.S. energy policy, history of unconventional gas and oil extraction, and the federal involvement in energy R&D programs. Energy independence is analyzed in terms of three fundamental pillars (reducing the amount of imported oil, reducing the energy intensity of economy and increasing energy self-sufficiency). All of the models, schemes and calculations cover a period of 1973-2013. Two indicators -- improving self-sufficiency and decreasing energy intensity of the economy -- speak in favor of achievable energy independence. However, deficient energy balance suggests otherwise. In case the need to fill the gap between energy production and consumption by foreign oil imports (which have been at their historically highest values since the 1990s) remains, then a complete energy independence as well as security is just an illusion.
16

能源安全對美國中東外交政策工具選擇之影響-以美國石油產量為例 / The impact on energy security of US Middle East foreign policy tool of choice-A Case Study of American Oil Production

邱信國, Chiu, Hsin Kuo Unknown Date (has links)
美國擁有豐富的石油儲量,目前已探明的石油儲量即達到 485 億桶,居世界 第 9 位;同時也於 2014 年追過沙烏地阿拉伯,以平均每日 1164 萬桶的產量成為 世界上最大石油生產國。但另一方面,美國每日的石油消耗量,更大於歐洲及歐 亞大陸內 29 個國家的每日消耗量的總合,成為世界上最大的石油消費國。身為 世界上最大的能源消費國及戰後世界秩序的主導者,同時歷經一、二次世界大戰 及石油危機的重大衝擊後,深知能源的穩定供應是國家安全的重要基礎,美國必 須盡全力透過外交甚至軍事手段以確保能源的安全,所以歷屆政府都以能源安全 作為國家安全及外交政策的重點。 中東是目前全球己探明石油儲量最大的地區,也是全球石油產量最大的地區, 是以美國以能源戰略為導向的外交政策(簡稱能源外交)傳統上是以中東石油為 重心,美國也將中東地區的均勢與穩定、確保石油運輸通道的安全等視為其最根 本的國家利益之一。二次世界大戰之後,美國為了擴張或鞏固其在中東地區的影 響力而投入了大量的資源進行政治、經濟及軍事的干預。而頁岩油的出現使得美 國石油自給率大幅提高,對中東地區石油的依賴也迅速下滑。 頁岩油的出現是否會讓美國改變其向中東傾斜的外交政策,進一步將其全球 戰略部署重心進行調整至快速崛起的亞洲地區,值得我們觀察與探討。本論文以 文獻研究之方式,透過分析美國對石油進口的依賴程度與其在中東發生軍事衝突 時所採用的外交政策工具之間的關聯,嘗試探討在頁岩油革命大幅提高美國能源 自給率後,是否會影響美國對中東地區事務的干預程度。 本研究發現,石油進口比例的確影響了美國在中東地區所運用的外交政策工 具。石油進口比例高時,美國面對中東的跨國軍事衝突時傾向採取強度較高的外 交政策工具;石油進口比例低時,則採取干預強度較低的外交政策工具。是以本 研究認為,在頁岩油革命使美國進一步降低對進口石油的依賴後、將使中東這個 提供美國主要石油來源的地區的重要性降低。但另一方面,中東除了提供美國重 要的石油來源,亦是全球的石油供應中心,美國對中東地區的影響力不僅關係到 美國的能源安全,亦關係到美國全球霸權的地位。 / United States has abundant oil reserves that reserves reached 485 billion barrels, ranking No. 9 in the world; and also chase in 2014 over Saudi-Arabia, to 1164 million barrels of production per day on average to become the world largest oil producer. On the other hand, the US daily oil consumption, the greater the total combined daily consumption in Europe and Eurasia in the 29 countries, the world's largest oil consumer. As the world's largest energy consumer and the postwar world order leader, after a while, after the Second World War and the significant impact of the oil crisis, we know that stable supply of energy is an important basis for the national security of the United States must do efforts through diplomatic and even military means to guarantee energy security, the successive governments have focused on energy security as national security and foreign policy. The Middle East is currently the world's largest oil reserves in the region have been proven, is the world's largest oil production area, based on the US foreign policy-oriented energy strategy (referred to energy diplomacy) is traditionally focus on Middle East oil, the United States will in the Middle East balance and stability in the region, to ensure the safety of oil transport corridor, etc. regarded as one of the most fundamental interests of their country. After World War II, the United States in order to expand or consolidate its influence in the Middle East and put a lot of resources, political, economic, and military intervention. The emergence of shale oil self-sufficiency rate of such a substantial increase in US oil dependence on Middle East oil is also declining rapidly. Shale oil occurs whether the United States will change its foreign policy towards the Middle East tilt further its global strategic center of gravity to adjust to the rapid rise of Asia, we should observe and discuss. In this paper, after the manner of literature, through the analysis of foreign policy tools related U.S. dependence on oil imports and its military conflict in the Middle East used between attempts to discuss a substantial increase in US energy self-sufficiency rate in shale oil revolution, whether the United States will affect the level of intervention in the Middle East affairs. The study found that the proportion of imported oil does affect US foreign policy tool in the Middle East by the use of. A high proportion of oil imports, the United States when faced with cross-border military conflict in the Middle East tends to take a higher intensity of a foreign policy tool; low proportion of imported oil, then take a low intensity intervention foreign policy tool. The present study is that in the US shale oil revolution to further reduce the importance of post-import dependence on oil, the Middle East, will provide the main source of US oil region is reduced. On the other hand, the Middle East and the United States in addition to providing an important source of oil, is also a center of global oil supplies, the US forces in the Middle East not only to America's energy security, but also related to the status of US global hegemony.
17

Estudo da viabilidade técnica do uso do resíduo de óleo de xisto como óleo extensor em ligantes asfalto-borracha / Study of the technical viability of using shale-oil residue as extender oil in asphalt-rubber binders

Faxina, Adalberto Leandro 15 December 2006 (has links)
Ligante asfáltico e borracha moída de pneus são materiais, na maioria das vezes, de difícil compatibilização, exigindo a adição de produtos químicos que facilitem a dispersão e a incorporação da borracha, como, por exemplo, os óleos extensores. A presente pesquisa tem por objetivo verificar a hipótese de que o resíduo de óleo de xisto, por se tratar de um óleo aromático, presta-se bem como óleo extensor de borracha, permitindo, inclusive, a adição de teores de borracha maiores que os normalmente incorporados aos ligantes asfálticos na ausência de óleos extensores. A tentativa de verificação de tais hipóteses foi efetuada por meio de uma programação laboratorial dividida em duas etapas. A primeira englobou uma investigação sobre o efeito da borracha moída e do resíduo de óleo de xisto sobre características físicas de 27 ligantes asfálticos, a fim de modelar diversas propriedades reológicas desses materiais, tendo como variáveis previsoras as porcentagens de componentes e as variáveis de processo. Na segunda etapa, foram estudados 8 ligantes asfálticos, a fim de obter dados para a validação dos modelos definidos na primeira etapa e também para a modelagem de propriedades não contempladas na primeira fase. Em ambas as fases, o planejamento dos experimentos foi efetuado empregando a técnica estatística de experimentos com misturas. A caracterização física dos ligantes asfálticos foi efetuada por meio de ensaios tradicionais (ponto de amolecimento, penetração e resiliência) e da especificação Superpave (viscosidade aparente, balanço de massa, cisalhamento dinâmico e fluência na flexão), em ligantes virgens e submetidos às práticas de envelhecimento a curto e longo prazos indicadas pela especificação Superpave (RTFOT e PAV). Ensaios de estabilidade à estocagem também foram realizados. Há evidências de que o resíduo de óleo de xisto pode ser empregado como óleo extensor em ligantes asfalto borracha, porém a seleção das concentrações adequadas dos componentes (asfalto, borracha e resíduo de óleo de xisto) depende do monitoramento de propriedades reológicas nas temperaturas de ocorrência dos principais defeitos do pavimento na região de implantação da rodovia. / Asphalt binder and crumb rubber from discarded tires are materials that, most of time, are not compatible, requiring the addition of chemical products to facilitate the dispersion and incorporation of rubber particles as, for example, the extender oils. This research aims at evaluating the hypothesis that the shale-oil residue, once it is an aromatic oil, may be used as an extender oil for asphalt-rubber binders, allowing the incorporation of crumb-rubber proportions even higher than those usually added to asphalt binders without extender oils. The effort to verify these hypotheses was made by means of a laboratorial program divided in two steps. In the first step an investigation was carried out to assess the effects of crumb rubber and shale-oil residue on physical characteristics of twenty seven asphalt binders, in order to model rheological properties of these materials, using the component proportions and the process variables as predictor variables. In the second step, eight asphalt binders were studied, to obtain data to validate the original models and to model some properties that were not monitored in the first step. In both steps, the experiment was designed using the statistical technique of experiments with mixtures. The physical characterization of the asphalt binders was performed using traditional tests (softening point, penetration and resilience) and those of Superpave specification (apparent viscosity, mass loss, dynamic shear and flexural creep), with materials in three conditions: virgin, short-term aged (RTFOT) and long-term aged (PAV). Storage stability tests were also performed. There are evidences that the shale-oil residue can be used as an extender oil in asphalt-rubber binders, but the selection of the adequate concentrations of the components (asphalt, rubber and oil) depends on the measurement of rheological properties in the temperatures at which the main pavements distresses occurs in the place the road will be constructed.
18

Análise dos efeitos da borracha moída de pneu e do resíduo de óleo de xisto sobre algumas propriedades mecânicas de misturas asfáticas densas / Analysis of the effects of crumb rubber and shale-oil residue on mechanical properties of asphalt mixtures

Pilati, Fernanda 27 March 2008 (has links)
No Brasil, desde o início da década de 1990, vêm sendo desenvolvidas pesquisas sobre aplicação do asfalto-borracha visando tanto a diminuição dos problemas ambientais gerados pelo descarte de pneus inservíveis, como a melhoria das características dos ligantes produzidos. Dentro desse contexto, esta pesquisa teve por objetivo avaliar o desempenho mecânico de oito misturas asfálticas do tipo concreto asfáltico usinado a quente, produzidas com asfaltos convencional e convencional modificado com borracha de pneu e resíduo de óleo de xisto. Quanto ao ligante, foram utilizados 8 tipos, a saber: CAP 30/45 (referência); dois ligantes empregando teores diferentes de borracha moída de pneu; outros dois com teores distintos de resíduo de óleo de xisto e, por fim, mais três com combinações de teores de borracha e de resíduo de óleo de xisto. Os corpos-de-prova empregados nos ensaios foram moldados em cinco teores diferentes de ligantes asfálticos (4,5; 5,0, 5,5; 6,0 e 6,5%). Conseqüentemente, foram realizados ensaios Marshall, resistência à tração, módulo de resiliência e umidade induzida. Com base nos resultados dos ensaios realizados observou-se que tanto a borracha quanto o óleo reduzem a resistência à tração e o módulo de resiliência das misturas, no entanto, na recuperação retardada, os efeitos da borracha e do óleo são antagônicos, diminuindo e aumentando, respectivamente. Ademais, quanto à suscetibilidade à ação da água, as misturas com adição de óleo apresentaram menor suscetibilidade que as misturas com adição de borracha. Além disso, foi observado que todas as misturas estudadas, exceto aquelas com altas concentrações de óleo e de borracha, atenderam os requisitos estabelecidos pelas especificações, para as propriedades analisadas. Todavia, em alguns casos, considerando os efeitos antagônicos do óleo e da borracha, algumas combinações entre ambos podem ser realizadas, com a finalidade de alcançar os níveis desejados para as propriedades do ligante asfalto-borracha e das misturas asfálticas. / In Brazil, since the beginning of the 90\'s, have been developed researches on the application of asphalt-rubber seeking the reduction of environmental problems created by the used tires, and the improvement of the characteristics of the produced binder. Taking this into account, the purpose of this research is to evaluate the mechanical performance of eight hot mix asphalt concretes, produced with conventional asphalt and modified asphalt with crumb rubber and shale-oil residue. Eight types of binders were used: CAP 30/45 (reference); two binders using different crumb rubber contents, two with different shale-oil residue contents, and finally three more with the combination of crumb rubber and shale-oil residue contents. The specimens used in the laboratorial tests were compacted in five different binders contents (4.5; 5.0, 5.5; 6.0 e 6.5%). Hence, the tests performed are: Marshall test, indirect tension, resilient modulus and moisture induced. The results showed that the rubber and the shale oil reduce the indirect tension and resilience module of the mixtures, however, on the delayed recover, the effects of the rubber and of the shale oil are opposed, decreasing and increasing it, respectively. Moreover, for the moisture susceptibility, the mixtures with shale-oil residue exhibited less susceptibility to water than those with crumb rubber. Furthermore, all the studied mixtures, except those with high shale-oil residue and rubber concentrations, they got to attend the established requirements for the specifications, for the analyzed properties. Although, in some cases, considering the opposed effects of the shale oil and of the crumb rubber, some combinations between both can be accomplished, with the purpose of reach the levels wanted for the properties of the asphaltrubber binder and the asphalt mixtures. Also regression models were elaborated as for the analyzed properties. The results obtained of modeling were satisfactory.
19

Evaluation of the fatigue performance of fine aggregate matrices prepared with reclaimed asphalt pavements and shale oil residue / Avaliação do dano por fadiga em matrizes de agregado fino preparadas com misturas asfálticas fresadas e resíduo de óleo de xisto

Klug, Andrise Buchweitz 22 August 2017 (has links)
The incorporation of recycled asphalt pavements (RAP) in the production of new asphalt mixtures is a useful alternative to the use of virgin materials, leading to economic and environmental savings. Pavement recycling created a sustainable cycle of reuse of nonrenewable natural resources, reducing the demand for new mineral aggregate and binder. However, the addition of RAP, especially at higher percentages, increases the stiffness of the asphalt mixture, because of the high stiffness of the aged binder. High stiffness makes the asphalt mixtures more prone to fatigue cracking. In order to overcome such limitation and allow the incorporation of higher percentages of RAP, soften binders or rejuvenating agents are added to the mixture. The former act to reduce the high stiffness of the aged binder and the latter act to restore the aged binder properties to those required by the binder specifications. The shale oil residue is one of the most used rejuvenating agents in Brazil, and, according to the literature, its performance is comparable to other commercial rejuvenating agents, with the advantage of presenting higher rejuvenating potential, what is due to its higher aromaticity. The fatigue cracking process starts as micro cracks in the fine aggregate matrix (FAM) of the full asphalt mixture. One approach to investigate the fatigue process of the asphalt mixtures is based on the viscoelastic continuum damage theory (VECD), in which the process of micro cracking of a material can be represented by internal state variables associated with the reduction of the material integrity. In this study, tests on FAM samples were performed in order to evaluate the fatigue performance, and the results were analyzed by means of the VECD theory. The objective of this research was to evaluate the fatigue performance of FAMs produced with three RAP contents (20, 40 and 100%), two binders of different performance grades (PG 64-22 and PG 58-16), and the combination of new binder (PG 64-22) and rejuvenating agent (shale oil residue) at different binder/agent rates (100/0, 50/50 and 0/100). Out of the FAMs prepared with RAP, two presented fatigue performance superior to the control mixture (compounded with only new materials): the FAM prepared with 40% of RAP and PG 64-22 and the FAM prepared with 20% of RAP and PG 58-16. The shale oil residue did not play its role of rejuvenating the aged binder for most cases, probably because of the low diffusion rate of the material into the aged binder. / A incorporação de misturas asfálticas fresadas na produção de misturas asfálticas novas é uma alternativa útil à utilização de materiais novos, gerando benefícios econômicos e ambientais. A reciclagem de pavimentos criou um ciclo sustentável de reuso de recursos naturais não-renováveis, reduzindo a demanda por agregado mineral e asfalto novos. No entanto, a adição do material fresado, especialmente em proporções altas, provoca aumento na rigidez da mistura asfáltica, causado pela alta rigidez do asfalto envelhecido. Uma elevada rigidez pode tornar a mistura asfáltica mais propensa ao trincamento por fadiga. Para contornar tal desvantagem e permitir a adição de maiores quantidades de material fresado, asfaltos de baixa consistência e agentes de rejuvenescimento podem ser adicionados à mistura. Os asfaltos de baixa consistência atuam para reduzir a rigidez do asfalto envelhecido e os agentes de rejuvenescimento atuam para restaurar as propriedades originais do asfalto envelhecido, aproximando-as das exigidas pelas especificações para asfaltos virgens. O resíduo de óleo de xisto é um dos agentes rejuvenescedores mais utilizados no Brasil e, segundo a literatura, resulta em desempenho comparável ao desempenho de outros agentes rejuvenescedores comerciais, com a vantagem de apresentar maior poder de rejuvenescimento devido à sua maior aromaticidade. O processo de trincamento por fadiga principia nas microtrincas presentes na matriz de agregado fino (MAF) da mistura asfáltica. Uma abordagem para avaliar o comportamento à fadiga das misturas asfálticas é baseada na teoria do dano contínuo em meio viscoelástico, pela qual o processo de trincamento do material é representado por variáveis de estado interno associadas à redução na integridade do material. Neste estudo, ensaios em amostras de MAF foram feitos para caracterizar o desempenho à fadiga, e os dados foram analisados utilizando a teoria do dano contínuo em meio viscoelástico. O objetivo da pesquisa foi avaliar o desempenho à fadiga de MAFs produzidas com três proporções de material fresado (20, 40 e 100%), dois asfaltos com diferentes graus de desempenho (PG 64-22 e PG 58-16), e três combinações (100/0, 50/50, 0/100) de asfalto PG 64-22 e agente de rejuvenescimento (resíduo de óleo de xisto). Dentre as MAFs preparadas com material fresado, duas apresentaram desempenho à fadiga superior à mistura de controle (composta apenas com materiais novos): a MAF composta com 40% de material fresado e PG 64-22 e a MAF composta com 20% de material fresado e PG 58-16. O resíduo de óleo de xisto não atuou como rejuvenescedor do asfalto envelhecido, para a maioria dos casos avaliados, provavelmente devido à baixa taxa de difusão do material no asfalto envelhecido.
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Estudo da viabilidade técnica do uso do resíduo de óleo de xisto como óleo extensor em ligantes asfalto-borracha / Study of the technical viability of using shale-oil residue as extender oil in asphalt-rubber binders

Adalberto Leandro Faxina 15 December 2006 (has links)
Ligante asfáltico e borracha moída de pneus são materiais, na maioria das vezes, de difícil compatibilização, exigindo a adição de produtos químicos que facilitem a dispersão e a incorporação da borracha, como, por exemplo, os óleos extensores. A presente pesquisa tem por objetivo verificar a hipótese de que o resíduo de óleo de xisto, por se tratar de um óleo aromático, presta-se bem como óleo extensor de borracha, permitindo, inclusive, a adição de teores de borracha maiores que os normalmente incorporados aos ligantes asfálticos na ausência de óleos extensores. A tentativa de verificação de tais hipóteses foi efetuada por meio de uma programação laboratorial dividida em duas etapas. A primeira englobou uma investigação sobre o efeito da borracha moída e do resíduo de óleo de xisto sobre características físicas de 27 ligantes asfálticos, a fim de modelar diversas propriedades reológicas desses materiais, tendo como variáveis previsoras as porcentagens de componentes e as variáveis de processo. Na segunda etapa, foram estudados 8 ligantes asfálticos, a fim de obter dados para a validação dos modelos definidos na primeira etapa e também para a modelagem de propriedades não contempladas na primeira fase. Em ambas as fases, o planejamento dos experimentos foi efetuado empregando a técnica estatística de experimentos com misturas. A caracterização física dos ligantes asfálticos foi efetuada por meio de ensaios tradicionais (ponto de amolecimento, penetração e resiliência) e da especificação Superpave (viscosidade aparente, balanço de massa, cisalhamento dinâmico e fluência na flexão), em ligantes virgens e submetidos às práticas de envelhecimento a curto e longo prazos indicadas pela especificação Superpave (RTFOT e PAV). Ensaios de estabilidade à estocagem também foram realizados. Há evidências de que o resíduo de óleo de xisto pode ser empregado como óleo extensor em ligantes asfalto borracha, porém a seleção das concentrações adequadas dos componentes (asfalto, borracha e resíduo de óleo de xisto) depende do monitoramento de propriedades reológicas nas temperaturas de ocorrência dos principais defeitos do pavimento na região de implantação da rodovia. / Asphalt binder and crumb rubber from discarded tires are materials that, most of time, are not compatible, requiring the addition of chemical products to facilitate the dispersion and incorporation of rubber particles as, for example, the extender oils. This research aims at evaluating the hypothesis that the shale-oil residue, once it is an aromatic oil, may be used as an extender oil for asphalt-rubber binders, allowing the incorporation of crumb-rubber proportions even higher than those usually added to asphalt binders without extender oils. The effort to verify these hypotheses was made by means of a laboratorial program divided in two steps. In the first step an investigation was carried out to assess the effects of crumb rubber and shale-oil residue on physical characteristics of twenty seven asphalt binders, in order to model rheological properties of these materials, using the component proportions and the process variables as predictor variables. In the second step, eight asphalt binders were studied, to obtain data to validate the original models and to model some properties that were not monitored in the first step. In both steps, the experiment was designed using the statistical technique of experiments with mixtures. The physical characterization of the asphalt binders was performed using traditional tests (softening point, penetration and resilience) and those of Superpave specification (apparent viscosity, mass loss, dynamic shear and flexural creep), with materials in three conditions: virgin, short-term aged (RTFOT) and long-term aged (PAV). Storage stability tests were also performed. There are evidences that the shale-oil residue can be used as an extender oil in asphalt-rubber binders, but the selection of the adequate concentrations of the components (asphalt, rubber and oil) depends on the measurement of rheological properties in the temperatures at which the main pavements distresses occurs in the place the road will be constructed.

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