O módulo de resiliência é um parâmetro de crucial importância nas análises mecanísticas que envolvem a estimativa das tensões e deformações na estrutura do pavimento e no seu subleito, quando da ação do tráfego. Embora ensaios de campo possam ser empregados para se determinar o MR, a grande maioria das pesquisas nesse sentido são desenvolvidas em laboratório, onde é possível um maior controle das condições da amostra, dos sistemas de aplicação de carregamento e de medida dos deslocamentos. Entretanto, os ensaios em laboratório que visam à determinação do MR ainda são considerados especiais e exigem equipamentos relativamente complexos, ensejando portanto, pesquisas com a finalidade de se obter expressões que estimem o MR a partir de parâmetros advindos de ensaios mais simples e rotineiros. Neste trabalho foram realizados ensaios triaxiais dinâmicos para a determinação do módulo de resiliência de três solos empregados em rodovias do nordeste brasileiro. Através dos resultados de laboratório, verificou-se o desempenho dos modelos mais comumente empregados para se representar a variação do módulo de resiliência em função do estado de tensão. Observou-se para os três solos desta pesquisa, que o MR foi mais influenciado, quanto ao estado de tensão, pela tensão de confinamento e pela tensão principal maior. Analisou-se, por fim, a existência de uma expressão matemática entre o módulo de resiliência obtido a partir dos ensaios triaxiais dinâmicos e o módulo tangente inicial proveniente de ensaios de compressão simples, sob diversos níveis de tensão. Os resultados mostram que este tipo de associação é promissora, mas exige-se que o universo de solos estudados seja ampliado para que se estabeleça uma inferência decisiva. / Resilient modulus is a crucial parameter in mechanistic analysis involving the estimation of stress and strains under the pavement structure subjected to traffic loading. While field tests can be used to determine the dynamic behavior of soils, most researches favor laboratory tests. Such preference is based on the fact that laboratory tests are less constrained because of their carefully controlled conditions. Unfortunately these tests are still unusual due to relative complex equipment, therefore researches involving the correlation of resilient modulus from repeated load triaxial tests with other test results is needed. In this work, repeated load triaxial tests were performed on three soils used in northeastern Brazilian roadways to estimate the resilient modulus. The performance of the models most commonly adopted to represent resilient modulus as a function of state of stress were verified. lt was observed for the three soils in this research, that confining stress and principal major stress influenced resilient moduli values. Predictive equations correlating the resilient modulus from repeated load triaxial tests and parameters from compressive strength tests, considering different states of stress were investigated. lt was shown that this type of empirical correlation presented satisfactory results, although incisive conclusions can\'t be drawn without a wider number and variety of soils.

La cantidad de residuos se ha incrementado con el paso del tiempo, siendo actualmente una amenaza grave para el medio ambiente; tal es el caso del vidrio plano, el cual genera cantidades considerables de merma poco reutilizables en su producción. Esto ha generado que sus residuos reciban una mayor atención por las autoridades e investigadores a nivel global en los últimos años, proponiéndose usos respetuosos que contribuyan hacia un entorno más sostenible. Este estudio profundiza en la utilización del residuo de vidrio plano para la reducción de su merma y lo propone como una solución en la elaboración de un concreto ecológico, al ser incluido de forma pulverizada como adición en el concreto. Para ello, se hicieron diferentes diseños de mezcla con porcentajes variables de vidrio plano pulverizado, realizándose comparaciones con respecto a un concreto patrón para identificar su efecto en las propiedades del concreto; evaluándose los ensayos de asentamiento, resistencia a la compresión y resistencia a la compresión en condiciones de ataque por sulfatos. Los resultados muestran que la adición de vidrio plano pulverizado contribuye a la mejora del asentamiento, la resistencia a la compresión y la resistencia a la compresión en condiciones de ataque por sulfatos; y también, presenta un ahorro económico con respecto al concreto patrón. / The amount of waste has increased over time, currently being a serious threat to the environment. Such is the case of flat glass, which generates considerable quantities of waste that are not reusable in the production. This has generated that its residues receive a greater attention by the authorities and researchers to global level in the last years, proposing respectful uses that contribute towards a more sustainable surroundings. This study deepens in the use of the flat glass waste to reduce its shrinkage and proposes it as a solution in the elaboration of an ecological concrete. For this, different mixing designs were made with varying percentages of flat sprayed glass, making comparisons with respect to a concrete pattern to identify its effect on concrete properties; evaluated by slump tests, compressive strength and compressive strength in sulfate attack conditions. The results show that, the addition of pulverized flat glass contributes to the improvement of slump, compressive strength and compressive strength under sulphate attack conditions; and it presents an economic saving with respect to the reference concrete. / Trabajo de investigación

ABSTRACT IMPROVEMENT OF BEARING CAPACITY OF A SOFT SOIL BY THE ADDITION OF FLY ASH &Ouml / ZDEMIR, Murat Aziz M.Sc., Department of Civil Engineering Supervisor : Prof. Dr. Erdal &Ccedil / OK&Ccedil / A Co-Supervisor : Assoc. Prof. Dr. Murat G&Uuml / LER May 2011, 119 pages Soft soils are not suitable for use in runway and highway construction due to their undesirable characteristics such as poor grading, low strength, excessive plasticity, tendency to shrink or swell. By stabilizing such soils with appropriate agents, their engineering properties can be improved. One of the stabilizing agents is Class C fly ash. This study aimed at investigation of bearing capacity improvement of a soft soil (from Elmadag area) by using Class C fly ash (from Soma Thermal Power Plant). In the experimental study, index properties of soft soil and fly ash stabilized samples are determined. Then modified Proctor compaction, soaked California Bearing Ratio, and Unconfined Compressive Strength characteristics of the samples are investigated. During the study, the stabilized soil samples are prepared at different fly ash contents, i.e., 0%, 3%, 5%, 7%, and 10%. The samples are subjected to soaked California Bearing Ratio tests after 0, 7, and 28 days of curing. In addition to California Bearing Ratio tests, Unconfined Compressive Strength tests with 0, 7, and 28 days of curing are performed samples. For comparison purpose, hydrated lime is also used instead of fly ash in Unconfined Compressive Strength tests at predetermined contents, i.e., 3%, 5%, and 7%. In order to observe microstructures of samples, Scanning Electron Microscope - Energy Dispersive X-ray analysis are performed. The results of the study show that bearing capacity of Elmadag soft soil can be improved substantially and swell can be reduced significantly by using Class C fly ash.

The characteristics of fine aggregates, such as shape, angularity, and surface texture, have been shown to influence the performance of concrete and asphalt mixtures and to play an important role in obtaining valuable properties of early age concrete such as workability, and compatibility. However, the measurement of fine aggregate characteristics is not easy. In the present study, 26 fine aggregates, covering a wide spectrum of mineralogy, were examined using direct and indirect test methods in order to evaluate the shape, angularity, and surface texture, as well as to analyze the gradation. The direct test methods, such as AIMS and Camsizer, which provide a digital image of the aggregates proved to be the best. However, the cost of such systems can limit the use of digital imagining systems in practice. The indirect test methods which provide an estimate of aggregate surface characteristics, such as uncompacted void test, mortar flow test, compressive strength test, and flakiness test gave variable results. The uncompacted void test (Method A) was shown to be the most accurate indirect test method. The Camsizer and the sieve analysis test produced identical gradation analysis results when an adequate sample was used. General correlations were developed between the direct and indirect test methods. The non-approved fine aggregates on the TxDOT’s list were analyzed and compared to those of the approved fine aggregates to see whether they could be successfully used. It was found that both LS-5 and LS-8 had good results—even better than the results of some of the approved fine aggregates. Thus, they could be successfully used. / text

Fiber reinforcement is being widely used in concrete tunnel linings these days. Using fiber reinforcement can save not only cost, but also labor and time spent on construction. However, many owners hesitate to incorporate fiber reinforcement in tunnel lining due to lack of experience with and knowledge of the behavior of fiber reinforced concrete (FRC) In this study, fiber reinforced concrete was made with various kinds of fibers such as steel fiber, macro-synthetic fiber and hybrid fiber (a blend of macro-synthetic fiber and glass fiber). Many experimental tests were performed to investigate the compressive, flexural and shear behavior of fiber reinforced concrete. In addition to the structural capacity of FRC, the distribution of fiber reinforcement inside the concrete matrix was investigated. Test results of these experimental tests were thoroughly examined to compare and quantify the effects of fiber reinforcement. Next, the test results were used to generate axial force-bending moment interaction diagrams based on current design approaches. In addition, the current design approaches were modified to estimate the accurate and exact value of bending moment. Fiber reinforcement clearly improved the structural performance of tunnel lining. The post-peak flexural and shear strength was significantly influenced by the type and amount of fiber reinforcement. / text

In dieser Arbeit wurden das feldaktivierte Sinterverhalten sowie das geschwindigkeitsabhängige Druckfestigkeitsverhalten von WC-Co-Hartstoffen mit variierenden Bindergehalten untersucht. Dazu wurde eine Herstellungsroute für kornwachstumshemmerfreie near-nanokristalline WC-Co-Hartstoffe mit der Field Assisted Sintering Technique (FAST) entwickelt und genutzt, um Materialien mit Co-Gehalten von 2 bis 12 Ma.-% zu erzeugen. Gezielte Werkstoffzustände und Probengeometrien sind durch Anpassung des Sinterprozesses herstellbar. Ausgewählte WC-Co-Materialien mit Co-Anteilen von 6 bis 12 Ma.-% wurden unter Einfluss von Beanspruchungsgeschwindigkeit, Spannungszustand und Beanspruchungshäufigkeit hinsichtlich der Druckfestigkeit und des Versagensverhaltens charakterisiert.

In this thesis different mechanical properties for shotcrete (sprayed concrete) such as compression strength, bond strength, bending tensile strength, elastic modulus, free and restrained shrinkage as a function of its age was investigated. One of the main issues was to investigate the difference between ordinary cast concrete and shotcrete. Reliable material data for young and hardening shotcrete is scarce which in the past have made such comparisons difficult. Also, less accurate data representative for cast concrete has often been used in numerical modelling and design analyses. The focus of the project has particularly been on the properties bond strength and restrained shrinkage for which two new testing methods has been developed and evaluated. Microstructural studies have also been performed as a complement to the bond strength testing. The bond to rock is one of the most important properties for shotcrete used as rock reinforcement. During the very first time after spraying the physical properties and the bond to the rock depend on the set accelerator and the micro structure that is formed. The investigation of early age bond strength of shotcrete is of great importance both from a production perspective and a safety perspective. The newly developed method was tested and evaluated and proved that it can be used for bond strength testing already from a couple of hours after shotcreting. The bond, or adhesion, depends on several factors such as texture of the rock, the type of accelerator, application technique, etc. In this work the development of the microstructure in the interfacial transition zone (ITZ) and strength of the bond was investigated. The results show that the bond strength is related to the hydration process, i.e. the strength gain of the shotcrete. The early development of the ITZ was here studied using a scanning electron microscope (SEM) making it possible to observe changes over time, before and after proper cement hydration. Restrained shrinkage cracking of shotcrete, especially in the case of shotcrete sprayed on soft drains that are parts of a tunnel lining not continuously bonded to the rock, can be detrimental for the sustainability of an infrastructure tunnel system. Maintenance and repair costs can be high over time. It is shown that the developed test method realistically captures the behaviour of shotcrete drains on hard rock in situ. The method can be used in the evaluation of different technical solutions for avoiding or minimizing shrinkage cracks in shotcreted soft drains. It can also be used to assess the performance of shotcrete fully bonded to a rock surface, with respect to the ability to prevent cracking or to distribute possible shrinkage damage into several fine cracks instead of one wide. / <p>QC 20140526</p>

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-23T02:16:30Z No. of bitstreams: 1 JOELMA DIAS - TESE PPGEQ 2015..pdf: 4385285 bytes, checksum: ad15f959a3a9ae913e782ebf2f0869dd (MD5) / Made available in DSpace on 2018-03-23T02:16:30Z (GMT). No. of bitstreams: 1 JOELMA DIAS - TESE PPGEQ 2015..pdf: 4385285 bytes, checksum: ad15f959a3a9ae913e782ebf2f0869dd (MD5) Previous issue date: 2015-11 / CNPq / Neste trabalho, borra oleosa de petróleo foi submetida ao processo de estabilização por solidificação, o objetivo foi otimizar as respostas do processo, mostrando assim, o melhor tratamento relacionado a porcentagem de resíduo e tempo de cura, que leva a melhor resposta e indicar limites máximos permissíveis de demanda química de oxigênio e óleos e graxas para avaliar o material resultante. Para realizar a otimização e propor limites, inicialmente a borra oleosa de petróleo e o aglomerante foram caracterizados e classificados. Em seguida foi usado um planejamento do tipo fatorial com adição de três repetições no ponto central e adições de pontos axiais, no delineamento composto central rotacional. Os fatores adotados foram porcentagem de borra oleosa de petróleo e tempo de cura. Foi, também, realizada a confecção das matrizes cimentícias incorporadas com a borra oleosa de petróleo em função da otimização. Este material foi avaliado utilizando ensaios de integridade e durabilidade, imobilização dos contaminantes e avaliação ambiental. As matrizes cimentícias também foram caracterizadas usando ensaios de microscopia eletrônica de varredura, difração de Raios-X e análises termogravimétricas. Foi realizado o balanço de massa, análise da eficiência de retenção dos contaminantes, análise estatística e levantamento dos limites máximos permissíveis de demanda química de oxigênio, óleos e graxas em água potável e efluente para descarte no Brasil e no mundo. Do ponto de vista científico, uma das contribuições deste trabalho foi propor o limite máximo permissível para demanda química de oxigênio, que foi 1.000 (mil) miligrama por litro e, para o teor de óleos e graxas foi proposto 100 (cem) miligramas por litro, ambos para o ensaio de lixiviação. Para o ensaio de solubilização foi proposto 10 (dez) miligramas por litro para demanda química de oxigênio e 1 (um) miligramas por litro para o teor de óleos e graxas. Como resultado deste estudo foi demonstrado que a otimização das respostas é uma forma de minimizar e ou maximizar as variáveis respostas no processo de estabilização por solidificação, em que foi observado que os melhores resultados são obtidos, quando foram utilizados valores menores de porcentagem de borra oleosa de petróleo e tempo maior de cura. Este trabalho permite afirmar que é possível otimizar o processo de estabilização por solidificação de material estabilizado e solidificado incorporado com borra oleosa de petróleo e que a propositura de limites de avaliação ambiental contribui para assegurar uma adequada disposição de resíduo oleoso e uso adequado do produto final. / In this work, petroleum sludge oil was subjected to stabilization by solidification process, the objective was to optimize the process responses, thus showing the best treatment related to waste percentage and curing time, which leads to better response, and indicate oxygen chemical demand and oils and greases maximum permissible limits to evaluate the resulting material. To perform the optimization and propose limits, initially petroleum oily sludge and the binder were characterized and classified. Then it was used the factorial optimization with addition of three repetitions at the central point and additions of axial points, in the rotational central composite design. The adopted factors were petroleum oily sludge percentage and curing time. It was also performed the manufacturing of cementitious matrices incorporated with the petroleum oily sludge from the optimization. This material was evaluated through integrity and durability, immobilization of contaminants and environmental evaluation tests. Cementitious matrices were also characterized using scanning electron microscopy and X-ray diffraction tests and thermogravimetric analysis. The mass balance was performed, as well as contaminant retention efficiency and statistical analysis, and the determintaion of oxygen chemical demand and oils and greases maximum permissible limits in potable water and wastewater for disposal in Brazil and worldwide. From a scientific point of view, one of the contributions of this study was to propose the maximum permissible limit for oxygen chemical demand, which was one thousand (1,000) milligrams per liter and, for the oils and greases content was proposed one hundred (100) milligrams per liter, both for the leaching test. For the solubilization test was proposed ten (10) milligrams per liter for oxygen chemical demand and one (1) milligrams per liter for the oils and greases content. As a result of this study it was demonstrated that the responses optimization is a way to minimize and/or maximize the stabilization by solidification process response variables, in which was observed that the best results are obtained when lower petroleum oily sludge percentage and higher curing time values were used. This study allows us to affirm that it is possible to optimize the stabilization by solidification process of stabilized and solidified material incorporated with petroleum oily sludge and that the bringing of environmental evaluation limits helps to ensure a proper oily waste disposal and proper final product use.

Made available in DSpace on 2014-06-11T19:27:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-26Bitstream added on 2014-06-13T20:16:15Z : No. of bitstreams: 1 santos_lf_me_ilha.pdf: 6137370 bytes, checksum: 5de758f11cce6406d87fe87638a96bb5 (MD5) / O concreto auto-adensável (CAA) é um material que representa um dos maiores avanços na tecnologia do concreto das últimas décadas. O desenvolvimento do CAA propiciou eficiência e melhora nas condições de trabalho em canteiro de obras e na indústria de pré-moldados. Do ponto de vista reológico, o CAA é uma mistura fluida que proporciona diferenças de comportamento quando comparado ao concreto convencional. Neste contexto, a proposta desta pesquisa foi estudar, num primeiro plano, as características reológicas nas fases de pasta, argamassa e concreto do CAA no estado fresco e seu comportamento no estado endurecido. Para isso, optouse por empregar a metodologia de Repette e Melo (2005), que considera a resistência à compressão como ponto de partida para a composição do traço do CAA e que estuda os aspectos reológicos envolvidos nas diferentes fases de sua dosagem. Os materiais empregados para estudo de dosagem foram o fíler basáltico como adição, areia média, brita 19 mm, aditivo superplastificante e dois tipos de cimento. Foram elaborados dois concretos, com cimentos distintos, ambos com mesma classe de resistência igual a 40 MPa. Num segundo plano, foi realizado um estudo da avaliação da resistência à compressão desses concretos quando submetidos à cura térmica a vapor, variando-se as temperaturas de cura (entre 65oC e 80oC), assim como o patamar isotérmico de cura em 4 h,6 h e 8 h para cada temperatura. A avaliação das propriedades mecânicas dos concretos foi realizada empregando o Método da Maturidade. No emprego da maturidade foram utilizados as funções de Nurse e Saul e a proposta por Freiesleben-Hansen e Pedersen (FHP). As análises comparativas foram realizadas em função do tipo de cimento empregado, temperatura de cura e tempo de patamar isotérmico / The self-compacting concrete (SCC) is a material that represents one of the greatest advances in concrete technology in recent decades. The development of SCC has resulted in improved efficiency and working conditions at the construction site and the precast industry. Rheological point of view, the SCC is a fluid mix that provides behavior differences when compared to conventional concrete. In this context, the proposal of this research was to study, in the foreground, the rheological phases of paste, mortar and concrete of SCC in the fresh state and its behavior in the hardened state. For this, we chose to employ the methodology Repette e Melo (2005), which considers the compressive strength as a starting point for the composition of the trace of SCC and studying the rheological aspects involved in the different stages of their dosage. The materials used to study the dosage was basalt fillers such as addition, medium sand, gravel 19 mm, superplasticizer additive and two types of cement. We prepared two concretes with different cements, both with the same strength class of 40 MPa. In the background, a study assessing the compressive strength of concrete when subjected to steam curing, varying the curing temperatures (between 65oC and 80oC) as well as the level of isothermal cure at 4 h, 6 h and 8 h for each temperature. The evaluation of mechanical properties of concrete was carried out using the Maturity Method. Employment of maturity was used to Nurse e Saul function, as well as function proposed by Freiesleben-Hansen and Pedersen (FHP). Comparative analysis were performed according to the type of cement used, curing temperature and isothermal plateau

Made available in DSpace on 2014-12-17T14:06:52Z (GMT). No. of bitstreams: 1 FernandoAML.pdf: 704139 bytes, checksum: 56133b8802fd230583fd96ae8805d657 (MD5) Previous issue date: 2009-04-30 / Several problems related to the loss of hydraulic seal in oilwells, causing gas migration and/or contamination of the production zone by water, have been reported. The loss of the hydraulic seal is a consequence of cracks which can be occasioned either by the invasion of gas during the wait on cement or by the expansion of the casing causing the fracture of the cement sheath. In case of the pressure of the formation is higher than the pressure in the annulus, gas can migrate into the slurry and form microannulus, which are channels where gas migrates after the cement is set. Cracks can be also occasioned by the fracture of the cement sheath when it does not withstand the thermal and dynamic loads. In reservoirs where the oil is heavy, steam water injection operation is required in order to get the oil flowing. This operation increases the temperature of the casing, and then it expands and causes the fracture of the cement sheath in the annulus. When the failures on the cement are detected, remedial cementing is required, which raise costs caused by the interventions. Once the use of cement in the construction civil sector is older than its use in the petroleum sector, it is common to bring technologies and solutions from the civil construction and apply them on the petroleum area. In this context, vermiculite, a mineral-clay widely encountered in Brazil, has been used, on its exfoliated form, in the civil construction, especially on the manufacture of lights and fireproof concretes with excellent thermal and acoustical properties. It has already been reported in scientific journals, studies of the addition of exfoliated vermiculite in Portland cements revealing good properties related to oilwell cementing operations. Thus, this study aimed to study the rheological behavior, thickening time, stability and compressive strength of the slurries made of Portland cement and exfoliated vermiculite in 5 different compositions, at room temperature and heated. The results showed that the compressive strength decreased with the addition of exfoliated vermiculite, however the values are still allowed for oiwell cementing operations. The thickening time of the slurry with no exfoliated vermiculite was 120 min and the thickening time of the slurry with 12 % of exfoliated vermiculite was 98 min. The stability and the rheological behavior of the slurries revealed that the exfoliated vermiculite absorbed water and therefore increased the viscosity of the slurries, even though increasing the factor cement-water. The stability experiment carried out at 133 ?F showed that, there was neither sedimentation nor reduction of the volume of the cement for the slurry with 12 % of exfoliated vermiculite. Thus, the addition of exfoliated vermiculite accelerates the set time of the cement and gives it a small shrinkage during the wait on cement, which are important to prevent gas migration / Muitos problemas relacionados ? perda do isolamento hidr?ulico em po?os de petr?leo, causando migra??o de g?s e contamina??o da zona produtora por migra??o de ?gua, t?m sido reportados. A perda do isolamento hidr?ulico ? conseq??ncia de trincas que por sua vez s?o conseq??ncias de uma cimenta??o mal feita, onde houve invas?o de g?s durante a pega da pasta gerando trincas tamb?m chamadas de microanulares que s?o os caminhos por onde a migra??o de g?s ocorre. Essas trincas tamb?m s?o ocasionadas pela fratura do cimento quando este n?o suporta as cargas t?rmicas e din?micas, as quais o cimento ? submetido durante sua vida. Em reservat?rios onde o ?leo encontrado ? bastante viscoso, opera??es de inje??o de vapor de ?gua s?o requeridas a fim de facilitar o escoamento do ?leo. Essa opera??o aumenta a temperatura da malha de po?os, fazendo com que o revestimento dilate e frature o cimento no anular, ocasionando a perda do isolamento hidr?ulico. Uma vez detectada falhas no isolamento hidr?ulico, opera??es de corre??o s?o requeridas o que acaba gerando custos, perda de tempo com a interven??o e lucro cessante. Como o setor de constru??o civil trabalha com cimento a muito mais tempo que o setor de petr?leo, ? comum lan?ar-se m?o de tecnologias e solu??es apresentadas na constru??o e aplicar com os devidos ajustes no ramo do petr?leo. Nesse contexto, a vermiculita, um argilomineral encontrado em abund?ncia no Brasil, tem sido aplicado, na sua forma expandida, na constru??o civil para confec??o de concretos leves, resistentes a fogo e com excelentes propriedades de isolamento t?rmico e ac?stico. J? tem sido reportado em revistas cient?ficas, estudos de sua adi??o em cimento portland com boas propriedades relacionadas ? cimenta??o de po?os de petr?leo. Dessa forma o presente trabalho objetivou estudar o comportamento reol?gico, tempo de pega e a resist?ncia a compress?o de pastas com vermiculita expandida e cimento portland classe especial em quatro composi??es diferentes, fazendo um comparativo com as propriedades existentes da pasta padr?o contendo apenas cimento portland e ?gua, em duas temperaturas, ambiente e aquecida. Os resultados mostraram que a resist?ncia ? compress?o dos corpos de prova diminuiu com o aumento da concentra??o de vermiculita, por?m ainda dentro da faixa permitida para cimenta??o de po?os de petr?leo. Os ensaios de consistometria indicaram que o tempo de pega para a pasta padr?o foi de 120 min, enquanto que para a pasta com 12% de vermiculita expandida foi de 98 min. Os ensaios de estabilidade e a avalia??o do comportamento reol?gico das pastas mostraram que a vermiculita expandida por absorver ?gua, aumenta a viscosidade da pasta, mesmo aumentando o fator ?gua-cimento. O ensaio de estabilidade realizado ? 133 ?F mostrou que n?o houve rebaixamento e nem sedimenta??o para a pasta com 12% de vermiculita expandida. Logo a adi??o de vermiculita expandida ? pasta cimentante favorece a cura r?pida e a baixa retra??o do volume da pasta durante a pega, importantes para evitar migra??o de g?s