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In any underground facilities especially tunnels, it is essential to seal the area against water ingress and leakage of reserved materials. Grouting is a common method used to seal rocks around tunnels, successful grouting reduces the duration and cost of the construction, guarantees better working environment and higher safety, minimizes the maintenance and most important decreases the corresponding environmental hazards significantly. Achieving a sufficient grout spread is one of the prerequisites for a successful and efficient sealing, the penetration of a grout is defined as the length of how far grout penetrates in the rock through fractures from a bore hole. Chemical grouts and cement-based grouts are the prevailing ones among the grouting materials. Despite the better penetrability of chemical grouts, they are unfavorable to use due to environmental hazards associated to them, whilst cement-based grouts are more convenient to use because of their low cost and low environmental impact.The major drawback with cement-based grouts is their limited ability to penetrate the very narrow fractures which is directly related to their filtration tendency which is defined as the tendency of cement grains to agglomerate and build an impermeable filter cake during the flow. Many previous studies investigated the factors that affect the filtration tendency. They drew different conclusions and suggested various methods to improve the penetrability of cement-based grouts.The mixing method is one of the factors that have a great influence on the penetrability of the grout. An effective mixing method improves the dispersion of cement particles in the mixture, thus the penetrability of the grout. As it is known from previous studies, the finer the cement particles the harder to disperse. Grouts based on micro-fine cement (< 30 μm) are essential for the development of grouts that can seal very narrow fractures (20-50) μm compared to (70-80) μm at the present.In this study, the dispersion efficiency of three different mixing methods was evaluated, a conventional lab dissolver equipped with 90-mm disk, a conventional lab dissolver equipped with R/S system and an ultrasound UP400St device. Two cement types, INJ30 and UF12, that are similar in chemical composition but differ in degree of milling were tested. Dispersion was tested with filter pump.The results showed that the conventional lab dissolver equipped with 90-mm disk is ineffective method. The conventional lab dissolver equipped with R/S system is a better method compared to the 90-mm disk but still not effective enough especially when it comes to grouts based on ultra-fine cement (UF12). The ultrasound dispersion is not only the best method between the three methods in comparison, but even more stable and reliable. The best result obtained was grout based on UF12 passing through the 54 μm filter. This could mean that fracture aperture down to 55 μm now can be sealed. This is a significant improvement but there is still a marginal for further improvements. In combination with the dispersion efficiency of different dispersion methods, the study investigated the effect of additives on dispersion in particular and penetrability in general. Results showed that additives do not directly contribute to better dispersion, but they are necessary for better spread since they affect the flow properties.

<p>Grouting as a method of strengthening and sealing rock, soil and concrete is widely used. The possibilities of sealing structures are of great importance from both an economical and environmental point of view. The cost of grouting has in certain projects been as high as the cost for the blasting and excavation of the tunnel. To improve the technique of grouting with cement based material, it is necessary to focus on the properties of the used grout mixture. The ability of a grout to penetrate cavities, channels and porous material, the penetrability, depends on two things, the theology and the filtration tendency. Extensive laboratory tests on stable, low w/c-ratio, injection grouts show that the most significant limitation to their penetrability is the tendency of cement grains to agglomerate into an impermeable filter cake. The properties of a grout that may prevent passing obstructions in the flow path without the cement grains clogging and preventing further penetration is in this work called filtration tendency. An inert material mixture and a cement-based mixture are used for the investigations in this work. The inert material, which is crushed dolomite stone, does not react with the added water in the mixture. The used cement grouts are based upon three types of commercial available Portland cements and four Portland cements with modified grain size distribution curves. </p><p>Performed tests show that the grain size and grain size distribution is of great importance for the filtration tendency. According to performed experiments with inert and cement material, it seems to be advantageous for the penetrability to have a grain size distribution that contains neither too many fine or coarse grains. It is reasonable to believe that the grain size distribution should be relatively steep (narrow grain size range) between minimum and maximum grain size. The maximum grain size is of importance in terms of for example d_95. Too large maximum grain size will prevent penetration of the mixture through obstructions in the flow path. According to performed tests, the value of d₉₅, should be between </p><p>4-10 times smaller than the aperture to be penetrated by the cement based mixture. The small grain sizes are also of importance in order to achieve a low filtration tendency of the grout. This is because of the increased tendency for the small grains to flocculation into larger agglomerates, compared to larger grain sizes. </p><p>The filtration experiments with cement based grouts show that influences of parameters like surface chemistry (use of superplastisisers) and cement chemistry (hydration of cement grains) will strongly affect the filtration tendency of the mixture. </p><p>To visualize the phenomenon of filtration tendency it can be investigated on a larger scale than usually takes place. Filtration experiments in the scale of approximately 100:1 have been performed in order to see influences of grain concentration, grain shape and the penetrated slot aperture. It can be seen that used grain sizes (monodisperse and inert mixture) should be approximately at least 2-3 times smaller than the aperture to be penetrated by the mixture. Numerical experiments of filtration tendency have also been performed to investigate the possibilities to numerically simulate the influence of grain concentration and slot aperture. The numerical experiments are based on Eulerian flow modelling.</p>

Ce travail de thèse porte sur l'étude des mécanismes de blocage d'un écoulement d'eau dans un milieu granulaire par injection d'un produit de colmatage, et s'inscrit plus généralement dans la problématique de l'érosion interne des sols (Projet National ERINOH). Cette recherche, à dominante expérimentale, s'appuie sur une modélisation physique unidimensionnelle. Pour cela, une conduite d'écoulement de 18 cm de diamètre intérieur et 300 cm de longueur maximale, constituée par plusieurs tronçons de 50 cm de longueur assemblés, a été développée. Celle-ci est tout d'abord remplie du matériau granulaire perméable à étudier ; on établit ensuite un écoulement d'eau permanent à pression imposée à l'amont ; finalement on vient injecter localement un produit de colmatage pour essayer de bloquer l'écoulement. Le dispositif est équipé de plusieurs capteurs de pression, de débitmètres, d'un turbidimètre afin de mettre en évidence les paramètres significatifs qui contrôlent le processus de blocage. Les paramètres expérimentaux sont les caractéristiques du milieu granulaire (type de sol, conductivité hydraulique, état de compacité…), les caractéristiques de l'écoulement (vitesses, gradients hydrauliques, régime de l'écoulement…), les propriétés rhéologiques du coulis d'injection (densité, viscosité, seuil de cisaillement…) et la technique d'injection associée. Sur la base des résultats obtenus, on propose des critères de blocage de l'écoulement combinant ces derniers paramètres sous une forme suffisamment simple, utilisable dans la pratique, pour répondre à la demande des industriels impliqués dans le projet de recherche ERINOH, qui sont confrontés à ces pathologies / The present PhD thesis focuses on the mechanisms of blocking permanent water flow through a granular soil by injection of a grout. This work is part of the more general problem of internal erosion of soils (French National Project ERINOH). This research, mainly experimental, is based on a one-dimensional physical modelling. For this, a new original prototype setup, allowing to generate permanent flow in a 18 cm inner diameter and 3 m long plexiglas pipe, has been developed. It is first filled with a highly permeable granular medium, then permanent flow of water is generated at controlled upstream pressure, and finally the grout is injected locally in order to try to block the water flow. The set-up is equipped with multiple pressure sensors, flowmeters, a turbidimeter to monitor the significant parameters that control the clogging process. The experimental parameters are the characteristics of the granular medium (soil type, hydraulic conductivity, density ...), the flow characteristics (flow rate, hydraulic gradient, flow regime ...), the rheological properties of the grout (density, viscosity, yield stress ...) and the associated injection technique. Based on the results obtained, clogging criteria are proposed, as a function of the parameters involved, in a simple form for use in practice.Key-words: internal erosion, clogging, injection, grout, bentonite, yield stress, viscosity.

O revestimento cerâmico deve ser considerado como um conjunto de materiais integrados formando o sistema revestimento cerâmico - SRC que, em uma primeira análise, significa a união de placa cerâmica, argamassa de assentamento e rejunte. Avaliando mais cuidadosamente este sistema, observa-se que não apenas os fatores indicados acima interferem em seu funcionamento, sendo necessário ter conhecimento sobre outros materiais (base, chapisco, emboço, impermeabilizantes etc), e ainda considerar aspectos relacionados à especificação dos materiais e procedimentos de aplicação. Muitos profissionais da construção civil não têm o entendimento desse sistema como um todo, cometendo erros de especificação e aplicação, podendo provocar o aparecimento de problemas e patologias. Neste trabalho foi realizada uma intensa pesquisa com os vários agentes do sistema revestimento cerâmico, com ênfase especial aos profissionais (arquitetos e engenheiros) com o intuito de descobrir as carências sobre o sistema em questão e, baseado nestas dificuldades, propõe um \'manual eletrônico\'sobre especificação do SRC. Este software trabalha de forma interativa com o usuário e permite realizar a especificação de ambientes diferenciados, considerando as necessidades do local e do uso. O objetivo é que esta ferramenta, ao ser utilizada corretamente, melhore a qualidade de projeto do SRC e, dessa forma, contribua para a diminuição da ocorrência de defeitos e patologias neste sistema. / The name ceramic tile identifies not only the tile, but defines the ceramic tile system, that means the combination of ceramic tile, adhesive and grout. Other materials are involved in this system, in the layers behind: masonry, plaster, concrete. Together, all these material totalises a unit and, to guarantee the quality of this system, two factors deserve attention: correct materials specification and correct application of the materials that compound the layers involved. A great number of architects and engineers do not realize that ceramic tiles are not only one product, but a range of product with different properties and suitable to different applications, in different exposure conditions. This behaviour is in the origin of most errors and imperfections in the buildings. The author of this work conducted a survey with architects and engineers that project, plan or construct buildings, to investigate theirs main lacks of information about ceramic tile system. Based on the results of the survey, it was prepared a software that intends to be a guide for these professionals, including cares in the specification and application of this system, to assure the quality of the covering and to reduce the possibilities of flaws\' occurrence after the building construction. This software can represent an important and interactive tool, ease to use and designed to the day-by-day work of architects and engineers, providing direct answers to theirs questions and contributing to increase the quality of the buildings.

Apesar do largo emprego da técnica de solo pregado em nosso país, pouquíssima pesquisa foi realizada sobre a resistência ao cisalhamento de interface solo-reforço (qs) e sobre a importância deste parâmetro no desempenho desta técnica de reforço in situ de taludes e escavações. Busca-se com esta tese, avaliar experimentalmente, a influência de diferentes metodologias executivas do chumbador (número de injeções) neste parâmetro. As informações para o desenvolvimento deste trabalho foram obtidas a partir de ensaios de arrancamento realizados em chumbadores construídos em duas obras nas cercanias da cidade de São Paulo, ou seja, em escala real. De forma complementar, também foi construído uma estrutura de solo pregado em laboratório. A partir dos ensaios realizados, observaram-se melhorias significativas na resistência ao cisalhamento de interface a partir das injeções do chumbador e estabelecer equações que relacionam o valor de qs com o volume injetado de calda de cimento, sendo uma importante ferramenta para analisar o desempenho do chumbador. O monitoramento ao longo do ensaio permitiu analisar os mecanismos de distribuição das cargas. Por fim, é apresentada uma proposta de metodologia para a realização do controle de qualidade do chumbador. / Besides the soil nailing technique being common practice in Brazil, there is little research on the shear strength of the soil-reinforcement interface (qs) and on the importance of this parameter on the performance of this in situ reinforcement technique of slopes and excavations. Accordingly, this study has the objective to experimentally evaluate the influence of different executive methodologies of the nail (i.e. number of grout injections) on the parameter qs. Data were obtained from in situ, full scale pullout tests performed on nails built in two construction sites near Sao Paulo city. Additionally, a soil nailing structure was built in laboratory. The results show that significant improvement is achieved on the soil-nail interface shear strenght by the number of grout injections. Moreover, the pullout tests on the nails provided quantification of this improvement. Consequently, it was possible to establish equations that relate the value of qs to the volume of cement grout injected, which is as important tool to evaluate the performance of the nail. Monitoring of the instrumentation during execution of the pullout tests allowed evaluation of the mechanisms of load distribution along the nails. Finally, a methodology is proposed for a quality control procedure on soil-nailed walls.

O revestimento cerâmico deve ser considerado como um conjunto de materiais integrados formando o sistema revestimento cerâmico - SRC que, em uma primeira análise, significa a união de placa cerâmica, argamassa de assentamento e rejunte. Avaliando mais cuidadosamente este sistema, observa-se que não apenas os fatores indicados acima interferem em seu funcionamento, sendo necessário ter conhecimento sobre outros materiais (base, chapisco, emboço, impermeabilizantes etc), e ainda considerar aspectos relacionados à especificação dos materiais e procedimentos de aplicação. Muitos profissionais da construção civil não têm o entendimento desse sistema como um todo, cometendo erros de especificação e aplicação, podendo provocar o aparecimento de problemas e patologias. Neste trabalho foi realizada uma intensa pesquisa com os vários agentes do sistema revestimento cerâmico, com ênfase especial aos profissionais (arquitetos e engenheiros) com o intuito de descobrir as carências sobre o sistema em questão e, baseado nestas dificuldades, propõe um \'manual eletrônico\'sobre especificação do SRC. Este software trabalha de forma interativa com o usuário e permite realizar a especificação de ambientes diferenciados, considerando as necessidades do local e do uso. O objetivo é que esta ferramenta, ao ser utilizada corretamente, melhore a qualidade de projeto do SRC e, dessa forma, contribua para a diminuição da ocorrência de defeitos e patologias neste sistema. / The name ceramic tile identifies not only the tile, but defines the ceramic tile system, that means the combination of ceramic tile, adhesive and grout. Other materials are involved in this system, in the layers behind: masonry, plaster, concrete. Together, all these material totalises a unit and, to guarantee the quality of this system, two factors deserve attention: correct materials specification and correct application of the materials that compound the layers involved. A great number of architects and engineers do not realize that ceramic tiles are not only one product, but a range of product with different properties and suitable to different applications, in different exposure conditions. This behaviour is in the origin of most errors and imperfections in the buildings. The author of this work conducted a survey with architects and engineers that project, plan or construct buildings, to investigate theirs main lacks of information about ceramic tile system. Based on the results of the survey, it was prepared a software that intends to be a guide for these professionals, including cares in the specification and application of this system, to assure the quality of the covering and to reduce the possibilities of flaws\' occurrence after the building construction. This software can represent an important and interactive tool, ease to use and designed to the day-by-day work of architects and engineers, providing direct answers to theirs questions and contributing to increase the quality of the buildings.

Atualmente, a alvenaria estrutural é utilizada em empreendimentos habitacionais de larga escala, nos quais as exigências de racionalização, controle, rapidez e custo são mais bem contemplados pelo sistema. No Brasil, existem empreendimentos de até 16 pavimentos construídos com blocos de alta resistência e alto controle tecnológico. A construção de edificações com maiores alturas exige o aumento da capacidade de absorção de esforços de compressão e tração. Para isso, são inseridas barras de aço nos vazados dos blocos e consolidadas com graute, a fim de aumentar a capacidade portante do conjunto. Entretanto, a influência da aderência graute/ bloco cerâmico no comportamento mecânico da alvenaria estrutural ainda é uma dúvida, visto que a NBR 15812 - 1 (ABNT, 2010) não especifica um valor de resistência para aderência graute/ bloco cerâmico, somente para graute/ aço. Frente a essa constatação, a presente pesquisa tem o objetivo de avaliar a influência da aderência graute/ bloco cerâmico estrutural no comportamento mecânico do conjunto, para determinar um valor de tensão de aderência que possa contribuir com a NBR 15812-1 (ABNT, 2010) Para isso, foram utilizados quatro tipos de blocos cerâmicos, com variação da geometria interna dos vazados e resistência mecânica à compressão. O graute foi padronizado em somente uma resistência, sendo essa de 30 MPa. Para desenvolvimento da pesquisa, inicialmente foi realizada a caracterização dos materiais e, posteriormente, realizados ensaios de push-out, resistência à compressão de blocos preenchidos com graute e microscopia óptica. Os resultados revelaram que a aderência graute/ bloco cerâmico estrutural é superior à resistência mecânica à tração do bloco cerâmico, e que a ruptura do conjunto ocorre primeiramente no bloco. Os resultados também constataram aumento da resistência mecânica à compressão axial nos blocos preenchidos com graute. / Currently, structural masonry is used in large-scale housing projects, in which the requirements of rationalization, control, speed and cost are better covered by the system. In Brazil there are projects of up to 16 floors built with high resistance and high technological control blocks. The construction of buildings with higher heights requires the increase of the capacity of absorption of compression and traction forces. For this, steel bars are inserted into hollow blocks which are then consolidated with grout in order to increase the load-bearing capacity of the assembly. However, the influence of ceramic block/grout adhesion in the mechanical behavior of structural masonry is still unknown since the NBR 15812-1 (ABNT, 2010) standard does not specify a resistance value for grout/ceramic block adhesion, only for grout/steel adhesion. In view of this finding, the present research has the objective of evaluating the influence of the structural ceramic block/grout adhesion on the mechanical behavior of the assembly in order to determine a value of adhesion tension that can contribute to the NBR 15812-1 (ABNT, 2010) standard For this purpose four types of ceramic blocks with a variation in the internal geometry of the hollow spaces and mechanical strength to compression were used. Grout was standardized in only one strength of 30 MPa. For development of the research, initially the characterization of the materials was performed and, subsequently, the tests of push-out and compressive strength of grout-filled blocks and light microscopy. The results showed that the grout/ceramic block adhesion is superior to the mechanical tensile strength of the ceramic block and, therefore, the rupture of the assembly will occur first in the block. The results also showed a significant increase of the mechanical resistance to axial compression in blocks filled with grout.

Tese de mestrado integrado. Engenharia Civil (Construções). Faculdade de Engenharia. Universidade do Porto. 2013

Tese de mestrado integrado. Engenharia Civil. Faculdade de Engenharia. Universidade do Porto. 2012