O concreto auto-adensável (CAA), que representa um dos mais significativos avanços na tecnologia de concreto, foi desenvolvido no Japão em 1988 com o intuito de se obter estruturas de concreto duráveis. É um concreto que dispensa o processo convencional de vibração ou adensamento por ter a capacidade de fluir e preencher os espaços da fôrma apenas através de seu peso próprio. Desde então, várias pesquisas têm sido realizadas e esse tipo de concreto já vem sendo aplicado na prática há algum tempo em alguns países, principalmente por grandes empresas de construção no Japão e na Suécia. Pesquisas para se estabelecerem métodos racionais de dosagem para CAA bem como métodos de ensaios no estado fresco têm sido desenvolvidas, visando fazer do CAA um concreto de aplicação comum. Contudo, ainda não se conhece bem este material e o que se nota é que a maioria dos CAA apresentados em trabalhos científicos é obtida com altos teores de argamassa, além da grande dispersão desses teores. Neste trabalho foi estudada a influência do teor de argamassa sobre as características de concretos auto-adensáveis, tanto no estado fresco como no estado endurecido, produzidos a partir de diferentes teores de argamassa (55, 60, 65, 70 e 75%). Para a produção dos mesmos foi aplicado um novo método de dosagem para CAA desenvolvido por Tutikian (2004), o qual se mostrou satisfatório no que diz respeito às propriedades de fluxo dos CAA. Em termos de resistências mecânicas os CAA´s obtidos apresentaram comportamentos bem similares uns aos outros para relações a/c aproximadas e mesmo teor de fíler calcário (que substitui parte do teor de agregado miúdo total) . Porém, o consumo de aditivo superplastificante tende a aumentar, para uma mesma fluidez, com o aumento do teor de argamassa, o que se caracteriza pelo aumento da superfície específica da mistura para altos teores de argamassa. Quando comparado com um concreto convencional com mesmo teor de argamassa o CAA apresentou qualidades similares ou ligeiramente superiores, com exceção de seu custo que é superior ao de um concreto convencional. Deste modo, o presente trabalho pretende contribuir para um melhor conhecimento e entendimento do CAA para que o mesmo possa ser aplicado com segurança em edificações e obras corrente de engenharia civil. / Self-compacting concrete (SCC), first developed in Japan in 1988 to achieve durable concrete structures, and adopted in Europe and the rest of the world more recently, represents one of the most significant advances in concrete technology. SCC is a type of concrete that can flow and compact in a mould or formwork under its own weight without the need for vibration. Since then, several research activities have been carried out and this type of concrete has been used in practical structures in Japan and Sweden, mainly by large construction companies. Investigations for establishing rational mix design methods for SCC and self-compactability testing methods have been developed from the point of view of making this new concrete a standard concrete. However, SCC is not well known so far and it can be observed worldwide that most of the SCC has been proportioned with high mortar/paste contents. This work aims to assess the influence of the mortar content in the composition of SCC on its properties, both in fresh and hardened states, produced with five different mortar contents (55, 60, 65, 70, and 75%). The newly-developed mix design method (TUTIKIAN, 2004) was applied to produce all SCC, and it seemed to be a very good method in terms of the SCC flow properties. Concerning the mechanical properties (compressive/tensile strength) all SCC produced in this study have presented similar results related to others with approximate water-to-cement ratio and the same limestone filler content (used to replace part of the total fine aggregate content). It was verified that the superplasticizer dosage increases as the mortar content increases for the same values of flow properties, which can be explained by the greater specific surface of the mixtures as the mortar content increases. Compared to a normal vibrated concrete with the same mortar content in its composition, SCC presented equal or slightly better qualities, excepting the issue of costs which is more expensive than those of the normal vibrated concrete. This dissertation aims to contribute for a better knowledge and understanding of SCC so it can be safely applied in buildings and in civil engineering projects.

A utilização do concreto auto-adensável (CAA) vem aumentando consideravelmente, no Brasil e no mundo. Com isso, há mais interesse em estudos práticos e teóricos a respeito do material, porém a maioria realizada está centrada em propriedades mecânicas da mistura no estado endurecido. Poucos estudos estão voltados para uma das áreas de maior lacuna: a dosagem. Os métodos de dosagem existentes para o CAA ou são experimentais, baseados na experiência do executor, ou são dependentes de tabelas determinadas a partir de materiais de difícil reprodução em outros locais. Com o intuito de ajudar a resolver este problema, foi proposto um método de dosagem experimental para CAA nesta tese. Este método visa a dosagem de CAA através de ensaios simples que determinem a composição dos agregados, de forma que o empacotamento granular apresente a menor quantidade de vazios possível, a fim de se minimizar o consumo de pasta na mistura. O método utiliza conceitos novos e já consagrados de outros métodos, como o IPT/EPUSP (Helene e Terzian, 1992), o proposto por Tutikian (2004), o de O´Reilly (1992) e o Modelo de Empacotamento Compressivo (CPM) (De Larrard, 1999). Para a comprovação da eficácia deste método, foram dosadas seis famílias de CAA, sendo três com areia fina e outras três com cinza volante, formando pares dosados por diferentes métodos. Entre as seis famílias, duas utilizaram o método de Tutikian (2004) e quatro o método proposto, porém primeiramente com uma faixa de agregado graúdo e após com duas granulometrias de brita, proporcionando famílias com o esqueleto granular mais compacto. Por fim, foi realizada uma família de concreto convencional (CCV). Os CAA dosados através deste novo método são de obtenção mais simples e menos trabalhosa, dependendo menos da experiência do executor, e os resultados mostraram que estes podem ser mais econômicos e com as propriedades no estado endurecido similares ou até vantajosas em relação às dos CCV e a dos outros CAA, principalmente o com duas granulometrias de agregado graúdo. / The utilization of self compacting concrete (SCC) has been increasing considerably throughout Brazil and the world. Hence, there has been more interest in theoretical and practical studies regarding the issue; however, the majority of such studies have been focused on the mechanical properties of the mixture in the hardened state. Very few studies have been focused on the subject of the dosage. The existing methods of dosage for SCC are either experimental, based on the experience of the executor, or are dependent on customized charts based on local materials which are very difficult to reproduce. With the intention to aid in the solution of this problem, an experimental dosage method was proposed in this thesis. This method aims at the dosage of SCC through simple tests that determine the composition of the aggregates, so that the packing density presents the least amount of voids, in order to minimize the consumption of binder in the mixture. The method uses new concepts and some concepts already determined from other methods, such as the IPT/EPUSP (Helene e Terzian, 1992), the one proposed by Tutikian (2004), the O´Reilly (1992) and the Compressive Packing Model (CPM) (De Larrard, 1999). In order to substantiate the efficienty of this method, six families of SCC were carried out, three of those with fine sand and the remaining three with fly ash, forming three pairs dosed by different methods. Amongst the six families, two used the Tutikian method (2004) and the other four families used the proposed method, which were divided into two subgroups; two with one class of gravel and the remaining subgroup utilizing two classes of gravel, supplying each family with a more compact granular skeleton. As a control group, a test family of conventional concrete (CCV) was produced. The SCC designed through this new method is simpler to obtain and requires less labor, depending less on the experience of the executor. The results present themselves as more economical and with the properties in the hardened state quite similar or even enhanced in relation to the ones of the CCV and the other SCC, specially with two classes of gravel.

A consolidação das técnicas de dosagem e fabricação de concretos auto-adensáveis com reduzida relação a/c pode ser considerada como um dos desenvolvimentos mais impactantes da nova tecnologia do concreto. No Brasil a utilização deste tipo de concreto, apesar de estar aumentando consideravelmente, ainda é relativamente modesta. Projeta-se, todavia, uma considerável expansão nos próximos anos, em função das vantagens que este material oferece. Por isso, várias instituições têm buscado aprofundar o conhecimento sobre o concreto auto-adensável (CAA), através de estudos e pesquisas sobre o comportamento e características desse novo material. Visando colaborar para um melhor conhecimento sobre as propriedades de concretos autoadensáveis no estado endurecido, foi efetuado um estudo sobre o comportamento, em termos de deformação instantânea e lenta, de vigas fabricadas com CAA. O programa experimental compreendeu a análise de seis vigas de concreto armado dimensionadas segundo as exigências da NBR 6118/2003.Para fabricação das mesmas foi utilizado um concreto convencional, com teor de argamassa de 55%, que serviu como referência, e dois concretos auto-adensáveis, com teores de argamassa de 55% (similar ao do convencional) e 60% (típico de concretos auto-adensáveis). As vigas permaneceram em carga durante aproximadamente cinco meses, durante os quais foi registrada a evolução dos deslocamentos transversais do centro e do terço médio. Os resultados experimentais foram comparados com valores numéricos obtidos através da norma brasileira e do emprego de um modelo computacional baseado em elementos finitos. De uma forma geral, verificou-se que concretos auto-adensáveis possuem comportamento similar ao concreto convencional, podendo ser utilizada, para o dimensionamento de peças com este concreto, a mesma norma utilizada para estruturas de concreto convencional. Verificou-se, porém, que o modelo simplificado da norma brasileira vigente para estimativa da deformação total de longo prazo não apresentou dados coerentes com os resultados coletados em ensaio, subestimando os valores obtidos. Uma análise mais precisa foi possível através de um modelo de elementos finitos. Verificou-se, todavia, que para avaliar o comportamento de vigas de concreto armado em ambiente similar ao do ensaio, é imprescindível a inclusão dos efeitos da retração. / Self-compacting concrete (SCC) is considered by many researchers and field engineers as one of the most important recent developments in concrete technology. Despite the considerable advantages that are associated with the use of this special concrete, its use in Brazil is still limited, although there is a growth trend. A strong market expansion is expected in a short period, reproducing what is now happening in Europe and the US. Therefore, many research institutions have been trying to increase the scientific knowledge about SCC, trough studies and researches focused on this new material. In this paper, a study about the immediate and long-term deflections of reinforced concrete beams using SCC is presented, aiming to increase the knowledge about the properties of the self-compacting concrete in its hardened state. In the experimental part of this study, a comparison between the maximum deflections registered in concrete beams under constant load, made with conventional and SCC concrete, is carried out. The experimental program involved the casting and testing of six beams with the same geometry, longitudinal and transversal reinforcement, and subjected to the same load pattern. The beam prototypes were designed according to the Brazilian standard NBR 6118/2003, with a 210cm span and an 18x10cm cross-section. Two types of concrete with different mortar contents have been used: one conventional concrete with a mortar content of 55%, and two SCCs with mortar contents of 55% and 60%. The beams were put under load during approximately five months. The mechanical properties of concrete have been determined and the maximum deflections have been measured throughout this period. The experimental results have been compared with numerical estimates obtained using procedures recommended by the Brazilian standard and with estimates from a FEM computational model. Overall, it was found that self-compacting concrete has a similar behavior to conventional concrete, for the same mortar content, and can be designed with the same criteria used for conventional concrete structures. The estimates obtained using the Brazilian standard, however, underestimated the maximum deflections in relation to the experimental data collected. Better estimates were obtained using the FEM model, when temperature and humidity data was used to account for the shrinkage.

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Submitted by Kamila Costa (kamilavasconceloscosta@gmail.com) on 2015-09-02T12:59:37Z No. of bitstreams: 1 Dissertação - Melquizedec A Rodrigues.pdf: 5096404 bytes, checksum: 822e44f66d8679d306ea87080653ce00 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-09-16T15:19:40Z (GMT) No. of bitstreams: 1 Dissertação - Melquizedec A Rodrigues.pdf: 5096404 bytes, checksum: 822e44f66d8679d306ea87080653ce00 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-09-16T15:26:22Z (GMT) No. of bitstreams: 1 Dissertação - Melquizedec A Rodrigues.pdf: 5096404 bytes, checksum: 822e44f66d8679d306ea87080653ce00 (MD5) / Made available in DSpace on 2015-09-16T15:26:23Z (GMT). No. of bitstreams: 1 Dissertação - Melquizedec A Rodrigues.pdf: 5096404 bytes, checksum: 822e44f66d8679d306ea87080653ce00 (MD5) Previous issue date: 2015-03-09 / Não Informada / The aim of this study is to determine the possible replacement percentage of cement per waste marbles and granites (WMG) of marble shops of Manaus in the production of self-compacting concrete (SCC). The methodology adopted was to hold various laboratory tests: characterization of each constituent material of the CAA; the rheological properties of SCC; and mechanical, physical and chemical properties in the hardened state of SCC. Two superplasticizers have been applied, one on the base and other salts of sulphonated polymer based whose optimum content was determined by testing the slurry Marsh cone. The coarse aggregates and kids were characterized by assays granulometry, specific weight; unit mass in loose state; and unitary mass compressed and dry. The WMG were subjected to density testing and analysis of Fluorescence X Ray. For fresh SCC in the following tests were performed: scattering, scattering T500, V funnel and L box; and Testing of Compressive Strength and flexion, absorption, voids index and the SCC Density in the hardened state, as well as tests on mortar bars to check possible Alkali Aggregate Reaction (AAR). The results were effective for most traits SCC, up to 30% of the cement replacement by WMG when the additive polymer base was used, and up to 20% replacement when the superplasticizer was sulfonated. Fresh in this SCC met the requirements of ISO 15823, behaving like proper concrete for use in most current applications. In the hardened state near showed compressive strength of 35 MPa, may also be used in the production of concrete floors. The resistance to bending achieved in around 7.0 MPa and satisfy the Brazilian standard 15805. For absorption values were comprised between 4.0% and 5.0%, lower than the values found in the literature, for voids and density values were close to other research, 10%. In AAR tests achieved the expansion was less than 0.10%, and the waste classified as harmless by Brazilian standard 15577-4. With the above it can be said that the residues from marble shops may have an alternative destination in civil construction. / O objetivo principal deste trabalho é determinar o percentual de substituição possível de cimento por resíduos de mármores e de granitos (RMG) das marmorarias de Manaus na produção de concreto autoadensável (CAA). A metodologia adotada foi a realização de vários ensaios laboratoriais: de caracterização de cada material constituinte do CAA; das propriedades reológicas do CAA; e das propriedades mecânicas, físicas e químicas do CAA no estado endurecido. Foram aplicados dois superplastificantes, um à base de sais sulfonados e outro à base de polímeros, cujo teor ótimo foi determinado por meio de ensaios de pasta no cone de Marsh. Os agregados graúdos e miúdos foram caracterizados por meio de ensaios de granulometria, massa específica; massa unitária em estado solto; e massa unitária em estado compactado e seco. Os RMG foram submetidos a ensaio de massa específica e análise de Fluorescência de Raios X. Para o CAA no estado fresco foram realizados os seguintes ensaios: Espalhamento, Espalhamento T500, Funil V e Caixa L; e Ensaios de Resistência à Compressão e à Flexão, Absorção, Índice de Vazios e Massa Específica do CAA no estado endurecido, bem como ensaios em barras de argamassas para verificar possível Reação Álcali Agregado (RAA). Os resultados mostraram-se eficazes para a maioria dos traços de CAA, com até 30% de substituição do cimento por RMG quando o aditivo a base de polímeros foi utilizado e de até 20% de substituição quando o superplastificante foi o sulfonado. No estado fresco esse CAA atendeu aos requisitos da NBR 15823, se comportando como concreto adequado para utilização na maioria das aplicações correntes. No estado endurecido apresentaram resistência à compressão próximas de 35 MPa, podendo também ser utilizado na produção de pavimentos de concreto. As resistências à flexão alcançadas, em torno de 7,0 MPa, e satisfazem a NBR 15805. Para absorção os valores ficaram compreendidos entre 4,0% e 5,0%, menores que os valores encontrados na literatura, para o índice de vazios e massa específica os valores ficaram próximos de outras pesquisas, 10%. Nos ensaios de RAA as expansões alcançadas foram menores que 0,10%, sendo os resíduos classificados como inócuo pela NBR 15577-4. Com o exposto pode-se afirmar que os resíduos de marmorarias podem ter uma destinação alternativa na construção civil.

Les bétons autoplaçants (BAP), développés depuis plusieurs années sont encore à l'heure actuelle qualifiés de « nouveaux bétons » car leur utilisation reste modeste bien qu'ils possèdent un fort potentiel de développement. Ce frein peut être expliqué par leur coût plus élevé, leur sensibilité à la ségrégation et à la fissuration due à leur fort retrait ainsi que par le manque de connaissances sur leur durabilité. Les BAP se distinguent des bétons ordinaires principalement par un dosage en éléments fins plus important. Ainsi, l'utilisation de fines additions minérales plus économiques et/ou plus écologiques dans ces bétons parait judicieuse sous certaines conditions. La présente thèse s'inscrit dans ce contexte et a pour objectifs de contribuer au développement de BAP plus écologiques et à l'étude de leur durabilité. Notre choix s'est porté sur deux ciments industriels à forte teneur en additions, le ciment CEM Ill à base de laitier de haut fourneau et le ciment CEM V à base de cendres volantes et de laitier de haut fourneau ainsi que sur deux additions minérales encore peu étudiées dans la littéraire : le métakaolin et un sédiment de dragage calciné. Différentes formulations dérivées d'une formulation de BAP de parement de référence à base de CEM 1 ont été mises au point. Les résultats des essais mécaniques et physico-chimiques menés sur les différentes formulations montrent un effet plus ou moins important des additions sur le comportement mécanique au jeune âge et un effet positif certain à plus long terme. Les résultats des mesures de retrait endogène et de dessiccation de l'état frais (plastique) à l'état durci bien hydraté montrent que certaines additions augmentent le retrait de dessiccation des BAP (laitier et sédiment calciné) alors que d'autres le réduisent considérablement (le métakaolin). L'effet indéniable des additions sur l'amélioration de certains indicateurs de durabilité (diffusion des chlorures et perméabilité au gaz) et sur l'augmentation de leur sensibilité à la carbonatation a été quantifié. L'influence assez complexe des différentes additions est étudiée à la lumière des analyses physico-chimiques et microscopique. Enfin, une modélisation mésoscopique est développée et appliquée aux BAP en vue d'une une étude paramétrique. L'effet de la forme des granulats et de leur concentration sur le comportement global en compression et traction d'éprouvette de SAP ainsi que l'effet de l'endommagement mécanique sur l'évolution de la perméabilité sont étudiés. / Self-compacting concretes (SCC), developed several years ago are still considered as “•novel concrete" as their use remains modest although they have a strong development potential. This is mainly due to their higher cos, their sensitivity to segregation and cracking due to their high shrinkage and also due to the lack of information about their durability. SCCs are distinguished from ordinary concrete mainly by their high content of paste. The use of supplementary cementitious materials (SCM), grow increasingly for economic and environmental reasons. This thesis falls within this context and aims to contribute to the development of greener SCCs and to the study of their durability.Two industrial blended cements containing high amounts of SCM, slag cement CEM Ill and CEM V cement containing slag and fly ash as well as two mineral additions still little studied in the literature: metakaolin and calcined dredged sediment are used. Various SCC mixtures derived from a reference SCC based on CEM 1 cement were developed. The results of the mechanical, physical and chemical testing on the different formulations show a greater or lesser effect of SCM on the mechanical behavior at early age and some positive effect over the long term. The results of measurements of the autogenous and drying shrinkage from fresh state (plastic) to well hydrated state show that some SCMs increase the drying shrinkage of SCCs (slag and calcined sediment) while ethers significantly reduce its amplitude (metakaolin).The undeniable effect of SCMs on improving some durability indicators (chloride diffusion and gas permeability) and on increasing the sensitivity to carbonation was quantified. The rather complex influence of the different SCMs is studied in the light of physicochemical and microscopie analyzes. Finally, mesoscopic modeling is developed and applied to SCCs for a parametric investigation. The effect of the shape of aggregates and their concentration on the overall behavior in compression and tensile SCC specimen as well as the effect of the mechanical damage on the evolution of permeability are studied.

Vibrating machinery like rock drills and compactors are becoming more prominent in modem industry. The vibrations of these machines can damage surrounding structures and foundations and be harmful to their operators. Hand arm vibration syndrome is one example of serious injuries suffered by operators of these machines. Due to the fact that these machines need to vibrate, vibration absorbers that minimise the vibrations of the machines cannot be used. In such cases vibration isolators are necessary to isolate the vibration between the vibrating machine and other bodies like the handle or foundations. A tuned vibration isolator is a type of isolator that is able to isolate a certain frequency very effectively. These isolators can retain low mass and high stiffness compared to traditional isolators and can obtain complete isolation at the isolation frequency if no damping is present. The liquid inertia vibration eliminator (LIVE) is such a tuned vibration isolator that makes use of hydraulic amplification, which result in a very compact design. A LIVE isolator was designed incorporating the variable stiffness spring and a variable damping mechanism. Equations for the damped natural and isolation frequency of the LIVE isolator were also derived. The reason for changing the stiffness was to be able to adjust the isolation frequency of the isolator to coincide with the excitation frequency that resulted in a more effective isolator. The variable stiffness spring consisted of two leaf springs mounted on top of each other and separated at the centre to stiffen the whole spring assembly. The leaf springs were separated by a wax actuator that was controlled with a closed loop displacement control system to form a smart actuator. A stiffness change of 2.7 times the original stiffness was obtained by separating the springs. The variable damping mechanism was to be able to control the amount of amplification of noise at the natural frequency. An experimental isolator was built and tested and resulted in a tunable vibration isolator. The isolation frequency of the isolator could be shifted from 22.8 Hz to 36.2 Hz and a transmissibility of 10% was achieved over that whole range. The variable damping mechanism increased the viscous damping ratio from 0.001 to 0.033. A control system was designed and implemented that tuned the isolator automatically to the excitation conditions. It incorporated an optimisation algorithm to determine the optimum settings and then kept the isolator at that setting until the excitation conditions change. The whole process was then repeated. A tunable vibration isolator was therefore successfully developed that can be used to isolate tonal vibrations very effectively. The isolation frequency and damping of the isolator can be changed while in operation and a transmissibility of 10% can be achieved at the isolation frequency. / Thesis (M Eng (Mechanical Engineering))--University of Pretoria, 2006. / Mechanical and Aeronautical Engineering / unrestricted

Subject of this master thesis deals with the concept of the machine for a roadside compacting. After analysing of current market situation the aim of this work is not only to replace the vibration plate by new machine with a cab and vibration rollers but also mainly the design of the machine. The reason is easier work and it fulfils all constructional and ergonomic requirements and puts emphasis on aesthetic. So it fills a gap in the market.

This Master thesis is focused on characterization of multicompound self-compacting heavy-weight mortars resistant against long lasting influence of ionizing radiation in the underground nuclear waste storage. It examines a specific combination of properties of heavy-weight concretes and self-compacting mortars while considering the ecological and energetic impact of their production, as well as the productibility of partial substitutions that do not have negative impact on material properties. The Experimental part provides a comprehensive overview of composition and properties of self-compacting heavy-weight mortars with varying percentages of cement-to-mortar ratio. Sample properties were evaluated based on mechanical test results, thermal analysis, differential scanning calorimetry, scanning electron microscopy and X-ray diffraction.