Dissertations / Theses on the topic 'FRCC'

2010 - 2011
The mechanical behavior of cement-based materials is greatly affected by crack propagation under general stress states. The presence of one or more dominant cracks in structural members modifies its response, possibly leading to brittle failure modes. The random dispersion of short steel fibers in cement materials is a new methodology used for enhancing the response in the post-cracking regime. The behavior of Fiber-Reinforced Cementitious Composite (FRCC), compared to conventional plain concrete, is characterized by several advantages, e.g., higher tensile and shear resistance, better post-cracking ductility, higher fracture energy, etc. In this framework, this thesis deals with both the experimental investigation and computational modeling of the mechanical behavior of FRCC. A great part of the work is intended at reporting the formulation and validation of a novel constitutive model aimed at simulating the stress-cracking response of FRCC and considering most complex fracture occurrences in mixed-modes of failure. Firstly, the results of an extensive experimental campaign, performed at the Laboratory of Materials testing and Structures (LMS) of the University of Salerno, is presented in which the possible influence of combining different fiber types on the resulting properties of Steel Fiber Reinforced Concrete (SFRC) is investigated. Particularly, the study concerns the four-point bending behavior of pre-notched SFRC beams where the influence of the amount of fibers and types on the first-crack strength and the whole post-cracking behavior is analyzed. After this, an innovative approach for reproducing the fiber effects on the cracking phenomena of the concrete/mortar matrix is proposed. The well-known discrete crack approach based on zerothickness interface elements is used to model the interaction between fibers and mortar as well as its degradation during fracture processes under mode I, II and/or mixed ones. The matrix degradation is modeled by means of a fracture energy-based softening law formulated in the framework of the flow theory of plasticity. Then, two fundamental aspects of the fiber-mortar interaction are considered in the model, i.e., the bond behavior of fibers bridging the crack opening and the dowel effect derived by possible relative transverse displacements of the two faces of the crack. The inclusion of fibers and the above two effects are taken into account by means of the well-known “Mixture Theory”. Particular emphasis and importance is dedicated to the description and modeling of the overall debonding behavior of fibers embedded in cementitious matrices. Actually, the adhesive interaction between fibers in concrete matrix is of key importance in controlling the postcracking response of FRCC. A unified formulation for simulating the overall bond behavior of fibers embedded in cementitious matrices is also presented. The proposed unified formulation is intended as a key element to be possibly employed in numerical models aimed at explicitly simulating the mechanical behavior of FRCC by taking into account the discrete nature of such materials and the contributions of the various constituents within the framework of the so-called meso-mechanical approach. The predictive capabilities of the aforementioned discontinuous approach for failure analyses of fiber reinforced cementitious composite are evaluated at different levels of observation. Particularly, the discrete crack formulation is employed and validated to simulate the fracture behavior of FRCC at constitutive, mesoscopic and macroscopic levels of observations. Several numerical results are performed to demonstrate if such proposal, based on the non-linear interface formulation, is capable to lead realistic predictions of failure processes of FRCC under different load scenarios and considering a wide spectrum of fiber contents and types. It is also analyzed if the proposed formulation is able to capture the significant influence of the fiber content on the maximum strength and post-peak ductility in mode I, II and mixed ones showing the capability of the cracking formulation to capture the complex interaction mechanisms between fibers and matrix. Furthermore, a simpler stress-crack opening model based on a hinge-crack approach, already available in the scientific literature, is proposed while the experimental results reported in this thesis are taken as reference for its validation. The model represents a reformulation of a fictitious crack model and is based on fracture mechanics concepts where the stress-crack opening relationship is accounted in a similar way obtainable by considering the pure “mode I” case of the discontinuous proposal formulated in general sense for mixed-modes of fracture. A closed-form solution for the stress-crack opening law with the explicit consideration of the fiber actions is considered for such a formulation. The model predictions, compared with the experimental measures, are performed to demonstrate the soundness of the model to reproduce the mechanical response of SFRC members in terms of Force-Crack Tip Opening Displacement (CTOD) curves. At last, both plain concrete and FRCC are analyzed and modeled by means of a novel microplanebased plasticity formulation. A continuum(smeared-crack) formulation, based on the non-linear microplane theory combined with the well-known “Mixture Theory”, is considered for describing the fiber effects on the failure behavior of FRCC. The constitutive formulation, failure analyses and the interactions between cementitious matrix and steel fibers are similarly approached as outlined for the discontinuous proposal. The capabilities of the microplane model to capture the significant enhancement in the post-cracking behavior of FRCC, with particular emphasis on the fracture and post-peak strengths, are finally evaluated by considering some experimental data available in scientific literature. [edited by author]
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Dans cette thèse, nous nous sommes intéressés aux équations différentielles fractionnaires. Nous avons commencé par l'étude d'une équation différentielle fractionnaire en temps. Ensuite, nous avons étudié trois systèmes fractionnaires non linéaires ; le premier avec un Laplacien fractionnaire et les autres avec une dérivée fractionnaire en temps définie au sens de Caputo. Dans le premier chapitre, nous avons établi les propriétés qualitatives de la solution d'une équation différentielle fractionnaire en temps qui modélise l'évolution d'une certaine espèce. Plus précisément, l'existence et l'unicité de la solution globale sont démontrées pour certaines valeurs de la condition initiale. Dans ce cas, nous avons obtenu le comportement asymptotique de la solution en t^α. Sous une autre condition sur la donnée initiale, la solution explose en temps fini. Le profil de la solution et l'estimation du temps d'explosion sont établis et une confirmation numérique de ces résultats est présentée. Les chapitres 4, 5 et 6 sont consacrés à l'étude théorique de trois systèmes fractionnaires : un système de la diffusion anormale qui décrit la propagation d'une épidémie infectieuse de type SIR dans une population confinée, le Brusselator avec une dérivée fractionnaire en temps et un système fractionnaire en temps avec une loi de balance. Pour chaque système, on présente l'existence globale et le comportement asymptotique des solutions. L'existence et l'unicité de la solution locale pour les trois systèmes sont obtenues par le théorème de point fixe de Banach. Cependant, le comportement asymptotique est établi par des techniques différentes : le comportement asymptotique de la solution du premier système est démontré en se basant sur les estimations du semi-groupe et le théorème d'injection de Sobolev. Concernant le Brusselator fractionnaire, la technique utilisée s'appuie sur un argument de feedback. Finalement, un résultat de régularité maximale est utilisé pour l'étude du dernier système
In this thesis, we are interested in fractional differential equations. We begin by studying a time fractional differential equation. Then we study three fractional nonlinear systems ; the first system contains a fractional Laplacian, while the others contain a time fractional derivative in the sense of Caputo. In the second chapter, we establish the qualitative properties of the solution of a time fractional equation which describes the evolution of certain species. The existence and uniqueness of the global solution are proved for certain values of the initial condition. In this case, the asymptotic behavior of the solution is dominated by t^α. Under another condition, the solution blows-up in a finite time. The solution profile and the blow-up time estimate are established and a numerical confirmation of these results is presented. The chapters 4, 5 and 6 are dedicated to the study of three fractional systems : an anomalous diffusion system which describes the propagation of an infectious disease in a confined population with a SIR type, the time fractional Brusselator and a time fractional reaction-diffusion system with a balance law. The study includes the global existence and the asymptotic behavior. The existence and uniqueness of the local solution for the three systems are obtained by the Banach fixed point theorem. However, the asymptotic behavior is investigated by different techniques. For the first system our results are proved using semi-group estimates and the Sobolev embedding theorem. Concerned the time fractional Brusselator, the used technique is based on an argument of feedback. Finally, a maximal regularity result is used for the last system

The appearance of degraded areas in Brazil has been increasing considerably along the years, causing countless damages to the environment. According to FAO (2005), approximately 16% of the total area of Brazil presents some state of soil degradation induced by human activities. In reason of this, the present study has as objective characterizes the Vetiver grass (Vetiveria zizanioides) for application in the recovery of areas degraded by erosion, through the installation of plots in field and accomplishment of a laboratory and field experimental program. This grass was chosen because of its special characteristics, especially the high tolerance to extreme conditions, little height and extensive root system. To reach the objective, it was considered the adaptation and growth of the plant in the studied substrata, analyzed in physical and chemical level. Besides, the mechanical properties of the Vetiveria zizanioides roots were evaluated, studying the increase in resistance imposed by roots in the soil, as well as its root tensile strength. In the same way, it was considered the soil losses generated by the water erosion in each plot with different implanted treatment. The results showed that the grass requires care in its initial growth phase as well as other plants; however, it is resistant and can survive under adverse conditions. Concerning shear strength, unlike the expected, the soil-root system presented smaller resistances than the soil without roots. Possibly the choice of the work scale was not the most appropriate, being recommended working with larger samples or to do the tests directly in field with larger size equipments. Confirming results reported by other authors, great variability was observed in the data regarding the root tensile strength. In the same way, it was ratified the trend of smaller diameters roots to present larger tensile strength. Regarding the soil losses, it was observed that the largest losses were generated in the control plots, where there was no type of soil cover, as well as in the area of larger inclination and larger spacing among the strings of the grass. In face of those results, it is verified that is not possible to assure the success of bioengineering techniques application in the recovery of degraded areas just with isolated studies. The interest on the subject is not exhausted with this research, so it is necessary to carry out additional researches on real scale.
O surgimento de áreas degradadas no Brasil tem aumentado consideravelmente ao longo dos anos, ocasionando inúmeros prejuízos ao meio ambiente. Segundo a FAO (2005), aproximadamente 16% da área total do Brasil apresenta algum estado de degradação do solo induzida por atividades antrópicas. Em razão disto, o presente estudo tem como objetivo caracterizar a gramínea Vetiveria zizanioides para aplicação na recuperação de áreas degradadas por erosão, através da instalação de parcelas em campo e realização de um programa de ensaios de laboratório e campo. A gramínea foi escolhida, em virtude de suas características especiais, notadamente a alta tolerância a condições extremas, pouca altura e extenso sistema radicular. Para alcançar o objetivo, considerou-se a adaptação e crescimento da planta nos substratos de estudo, analisados em nível físico-químico. Além disso, avaliaram-se as propriedades mecânicas das raízes do Vetiveria zizanioides, estudando o ganho de resistência imposta pela sua raiz no solo, assim como sua resistência à tração. Do mesmo modo, determinou-se a perda de solo gerada pela erosão hídrica em cada parcela de estudo com diferentes tratamentos implantados. Os resultados mostraram que a gramínea requer cuidados em sua fase inicial assim como outras plantas; no entanto, ela se mostrou resistente tendo sobrevivido a condições adversas. No tocante à resistência ao cisalhamento, ao contrário do esperado, as matrizes de solo-raiz apresentaram menores resistências do que o solo sem raiz. Possivelmente a escolha da escala de trabalho não foi a mais adequada, sendo recomendado trabalhar com corpos de prova maiores ou fazer os ensaios diretamente em campo com equipamentos de maior porte. Confirmando resultados reportados por diferentes autores, observou-se grande variabilidade nos dados referentes à resistência das raízes submetidas à tração. Da mesma maneira, ratificou-se a tendência de que raízes de menores diâmetros apresentam maiores resistências. Com relação à perda de solo, observou-se que as maiores perdas foram geradas nas parcelas de controle, onde não existiu nenhum tipo de recobrimento do solo, assim como na área de maior inclinação e maior espaçamento entre os cordões da gramínea. Em face desses resultados, verifica-se que não é possível assegurar o êxito da aplicação de técnicas de bioengenharia na recuperação de áreas degradadas apenas com estudos isolados. O interesse sobre o assunto não se esgota nesta pesquisa, de modo que o tema prescinde de pesquisas complementares a serem efetivadas em escala real.

In Brazil and abroad, the construction sector is well know as the largest user of natural resources and the largest producer of waste. The waste disposal becomes more difficult each day due to the high costs of transportation and also to the difficulty in finding areas which can achieve environmental requirements. In this context, the Brazilian National Environmental Committee (Conselho Nacional do Meio Ambiente, CONAMA), published in 2002 the CONAMA Resolution 307, establishing guidelines, criteria and procedures for the management of the waste generated by civil construction, assigning to the municipalities and to the large producers the responsibility to separate and dispose their waste in accordance with a suggested classification. According to research data, the largest proportion of civil construction wastes produced daily in Brazil comes from informal sites, involving small constructions, refurbishment and demolition activities. This way the small producers become responsible for the largest proportion of the waste generated. In this context, this research describes the results of the implementation of the mentioned resolution guidelines in a group of small construction sites in the area of Belo Horizonte, Minas Gerais (Brazil). Three new construction sites (residential, commercial and industrial) and a refurbishment site were chosen. They were monitored and, beyond the measurement of the input materials and the waste produced, indexes, which can be used in similar construction sites, were developed. The costs of each management phase were also obtained. The research conducted showed a large difference in the amount of waste produced in refurbishment (684 kg/m2) and new construction sites (average of 97,75 kg/m2). Its segregation at the production point allowed an improvement in organisation, hygiene conditions and occupational safety, as well as a simpler recycling and appropriate final disposal. It can also be ighlighted the potential reuse of the waste in the construction sites, the low cost of its management (average of 0,22% to new construction activities) and the fact that such management activities did not change the physical timeline of the construction sites assessed
No Brasil e no exterior, a indústria da construção civil se destaca como a maior consumidora de recursos naturais e a maior geradora de resíduos. A sua disposição final fica mais complicada a cada dia, devido aos elevados custos com transporte e à dificuldade na escolha de áreas que atendam aos requisitos ambientais. Devido a essa situação, o Conselho Nacional do Meio Ambiente (CONAMA) criou a Resolução CONAMA nº. 307, publicada em 2002, que estabeleceu diretrizes, critérios e procedimentos para a gestão dos resíduos da construção civil, atribuindo aos municípios e aos grandes geradores a responsabilidade de segregar e dispor seus resíduos de acordo com uma classificação sugerida. Conforme dados pesquisados, a maior parte dos resíduos da construção civil gerados diariamente no Brasil, provêm de eventos informais: pequenas obras de construção, reformas e demolições. Sendo assim, os pequenos geradores se tornam responsáveis pela maior parcela dos resíduos gerados. Em função disso, o presente trabalho vem relatar os resultados obtidos com a implantação das diretrizes desta resolução em um conjunto de obras de pequeno porte na região de Belo Horizonte (MG). Foram escolhidas três construções novas (residencial, comercial e industrial) e uma obra de reforma. Todas elas foram monitoradas e, além da quantificação dos insumos e dos resíduos gerados, foram obtidos índices que podem ser utilizados na gestão de obras do mesmo tipo. Também foi apurado o custo de todas as etapas do gerenciamento. Os estudos realizados mostraram uma grande diferença na quantidade de resíduos gerados entre a reforma (684 kg/m2) e as construções novas (média de 97,75 kg/m2). A sua segregação no momento da geração proporcionou uma melhoria na organização, nas condições de higiene e segurança do trabalho, e facilitou a sua reciclagem e a correta disposição final. Pode-se destacar ainda a possibilidade de reaproveitamento de resíduos na própria obra, o baixo custo do seu gerenciamento (média de 0,22% para as construções novas) e o fato desta gestão não ter alterado o cronograma físico das obras estudadas

The research describes the safety assessment for an embankment dam under the scenario of hypothetical backward erosion piping by probability methods, the case study being the embankment dam of the São Simão hydropower plant, in southcentral Brazil. The results identified critical points that justify more attention and prevention actions in order to avoid environmental impacts of embankment dam accidents. The performance methods for assessing the relative likelihood of piping failure was done by performance analysis and as a checked on event tree analysis (ETA), in order to assess the safety for embankment dam in study. The likelihood assessment of piping from the embankment took into account the dam zoning, filters, age of the dam, core soil types, compaction, foundation geology, dam performance, and monitoring and surveillance for 29 years of operation. The method involves the adjustment of the historical average probabilities of the three modes of progressive backward erosion: piping through the embankment, piping through the foundation and piping from the embankment into the foundation, by historic failures. The methods employed in this research are referred to as the UNSW method (University of New South Wales) and the ETA (Event Tree Analysis) method. The data base used to qualify the historical failures is composed by 1462 dams, which correspond to approximately 13% of world population of existing dams until 1982. The historical annual probability of failure of large embankment dams was estimated in 4,5 x 10-4 per dam per year, which is coherent the research results.
A pesquisa descreve a avaliação de segurança em barragem de terra, sob o cenário de erosão tubular regressiva (piping), por métodos probabilísticos, tendo como estudo de caso a barragem da UHE São Simão. Os resultados identificaram pontos críticos que merecem mais atenção e ações de prevenção para evitar impactos ambientais decorrentes de ruptura da barragem. Para avaliar a segurança da barragem em estudo e a respectiva probabilidade relativa de ruptura por piping, foram empregados os métodos de análise de performance e de análise por Árvore de Eventos (ETA). A avaliação de probabilidade de piping para o barramento considerou sua seção transversal típica, os seus filtros, o seu tempo de operação, os tipos de solo usado no núcleo, a compactação, a geologia da fundação, a performance da barragem, o monitoramento e a supervisão por 29 anos de operação. O método envolve o ajuste de probabilidades médias históricas de três modos de erosão tubular regressiva: piping através do barramento, piping através da fundação e piping do barramento para a fundação, considerando as rupturas históricas. Os métodos aqui referenciados são denominados UNSW (University of New South Wales) e ETA (Event Tree Analysis). A base de dados amostrais utilizada para a quantificação de rupturas e acidentes históricos compreendeu 1.462 barragens, as quais correspondem a aproximadamente 13% da população mundial de barragens existentes até 1982. A probabilidade anual de ruptura por piping em grandes barragens é estimada em 4,5 x 10-4 por barragem, a qual se mostrou coerente com o resultado da presente pesquisa.

The present work aims to show to the methodology used for attainment of a vegetal covering on the of Phosphogypsum stack located at the Industrial Complex of Uberaba of property of the company FOSFERTIL Fertilizantes Fosfatados S.A, aiming at the reduction of the visualimpact proportionated, as well as the prevention of erosive processes and the dispersion of particles. It also aims at evaluating this methodology through the statistics analysis of the experiment, evaluation of the vegetation and the substratum throughout 4 years of plantation.To accomplish that an ample diagnosis was made that involved the stacks of Phosphogypsum in Uberaba MG and Cubatão SP, being that this second had a espontanneausly formed vegetal covering, wich allowed to evaluate the diverse impediments to the growth ofvegetation in the stack of Uberaba. The main limiting factors to the growth of vegetation in the stack of Uberaba had consisted of very low pH, the superficial crust caused by the Phosphogypsum crystallization, theabsence of structures and porosity and the nutricional disequilibrium of the material, that demanded several tests to correct of these factors.Many tests for the correction of these impediments had been carried out, where it concludes that if a correction of the Phosphogypsum using soil, organic matter, dolomitic limestone and the sludge residues from a treatment lagoon existing at the company. After these measures the vegetal covering with good vegetative vigor that it occupied more than 95% of the planted surface would be obtained. Based on these tests definitive planting were carried through in the stack from the years of2002 to 2005, wich allowed to evaluate the behavior of the vegetation and the substratum formed as time passed, as well to investigate the main causes of imperfections verified in these plantings. It was concluded in this work that the employed methodology was a successful, not only forthe result of the vegetal covering in the plantings that were done, wich had always been superior to 95% of the experimental process, but also because it indicates that it can be reapplied in other existing stacks in the country and the world, as well as other industrial stacks of similar characteristics.
O presente trabalho mostra a metodologia empregada para a obtenção de cobertura vegetal sobre a pilha de Fosfogesso situada no Complexo Industrial de Uberaba de propriedade da empresa FOSFERTIL Fertilizantes Fosfatados S.A, visando a redução do impacto visualproporcionado pela mesma, bem como a prevenção de processos erosivos e a dispersão de particulados. Visa também avaliar esta metodologia através da análise estatística do experimento montado, avaliação da vegetação e do substrato ao longo de 4 anos de plantio.Para tanto foi realizado um amplo diagnóstico que envolveu as pilhas de Fosfogesso de Uberaba MG e de Cubatão SP, sendo que esta segunda possuía uma cobertura vegetal formada espontaneamente, que permitiu avaliar os diversos impedimentos ao crescimento de plantas na pilha de Uberaba. Os principais impedimentos ao crescimento de vegetação na pilha de Uberaba consistiram em um pH muito baixo, no encrostamento superficial causado pela cristalização do Fosfogesso, na ausência de estruturas e de porosidade e no desequilíbrio nutricional do substrato.Foram realizados diversos testes para correção destes impedimentos e concluiu-se que com a correção do Fosfogesso utilizando terra, matéria orgânica, calcário dolomítico e o resíduo da lagoa de tratamento existente na empresa, obtinha-se uma cobertura vegetal com bom vigorvegetativo e que ocupava mais de 95% da superfície plantada.Com base nestes testes foram realizados plantios definitivos na pilha durante os anos de 2002 a 2005, que permitiram avaliar o comportamento da vegetação e do substrato formado ao longo deste tempo, bem como investigar as principais causas de falhas verificadas nestes plantios. Conclui-se neste trabalho que a metodologia de cobertura vegetal empregada foi um sucesso, não só pelo resultado da cobertura vegetal nos plantios realizados, que sempre foramsuperiores aos 95% da área plantada, obtidos no processo experimental, mas também porque sinaliza a possibilidade de reaplicação em outras pilhas existentes no país e no mundo, bemcomo em outros aterros industriais de características semelhantes.

Uncontrolled emissions of biogas is a serious problem of local and global air pollution. The effects of the release of gases locally vary from simple bad odor to possible carcinogenic diseases in the community surrounding the landfill. In relation to global air pollution and climate changes, the main effect of the release of biogas is the increasing of greenhouse effect. The main objective of this study is to evaluate the biogas emissions at the Experimental Sanitary Landfill in Belo Horizonte. Field tests, using static flux chamber device, were carried out in order to measure biogas emissions through the final cover. Gas emissions in 6 drains present in the experimental sanitary landfill have also been measured. The results obtained in field studies enabled the comparison with calculated values using the empirical method LANDGEM from USEPA. The experimental sanitary landfill has two final cover configurations. The first, called capillary barrier consisted of 30 cm soil overlaying 30 cm of recycled construction and demolition waste, and the second layer, called evapotranspirative cover, with about 60 cm of soil. The estimative of CH4 and CO2 average flow through the final cover using the methodology of flux chamber were 375 kg and 353 kg, respectively, released to the atmosphere per day. The procedures used to determine the gas flow in system of drains indicated very low values, suggesting a small efficiency of the drains. The results confirmed that the experimental sanitary landfill is at methanogenic phase with high concentration of CH4 and CO2. Comparing the internal concentration of methane to the emissions from the final cover, it was observed qualitatively a reduction of methane concentration between 38 and 68%. This fact dation of methane in the final cover layer due to presence of methanotrophic bacteria. Comparisons of values found using flux chamber to the values calculated by the model LANDGEM presented a large variation. These values were similar when extremes values of the parameters suggested by the model were used
A emissão descontrolada do biogás em aterros sanitários é um grave problema de poluição atmosférica local e global. Os efeitos da liberação dos gases localmente variam do simples odor até possíveis doenças cancerígenas na comunidade circunvizinha ao aterro. Em relação à poluição atmosférica global, o principal efeito da liberação do biogás é o aquecimento do globo terrestre que vem gerando grandes discussões nos últimos anos. A presente pesquisa aborda estudos de emissões de biogás no Aterro Sanitário Experimental de Belo Horizonte. Foram realizados ensaios em campo, com a utilização de placa de fluxo estática, no intuito de mensurar as emissões de biogás pela camada de cobertura. Também foram avaliadas as emissões de gases pelos 6 drenos presentes no Aterro Experimental. Com os resultados obtidos nos estudos em campo, foi possível a comparação com valores calculados a partir do método empírico LANDGEM da USEPA. O aterro experimental possui duas configurações de camada de cobertura final. A primeira, denominada barreira capilar, constituída de 30 cm de solo fino sobreposto a 30 cm de resíduos de construção civil (entulho) reciclado, e a segunda camada, denominada evapotranspirativa, com cerca de 60 cm de solo fino. A estimativa do fluxo médio de CH4 e CO2 pela camada de cobertura encontrado utilizando a metodologia da placa de fluxo foi de 375 kg e 353 kg, respectivamente, emitidos para a atmosfera por dia. Os procedimentos utilizados para a determinação do fluxo de gases pelo sistema de drenos implantado no aterro sanitário experimental indicaram vazões muito baixas, sugerindo a pouca eficiência dos mesmos. Pode-se verificar que o aterro sanitário está na fase metanogênica de biodegradação dos resíduos com elevada presença de CH4 e CO2. Ainda que de forma qualitativa, foram observadas reduções entre 38 e 68% da concentração de metano, quando comparadas as concentração internas e os valores emitidos pela camada de cobertura. Esse fato sugere a possibilidade de oxidação do metano na camada de cobertura que ocorre pela ação de bactérias metanotróficas, no entanto, não foi constatado aumento na concentração de CO2. Comparações dos valores entre os valores obtidos em campo com os valores calculados pelo modelo LANDGEM diferiram bastante. Esses valores aproximaram-se quando foram utilizados valores extremos dos parâmetros de entrada no modelo.

In the last years, in Brazil and abroad, due to the increase of restrictions of the environmental legislation, the design and operation of safe facilities for municipal solid wastes disposal, such as the sanitary landfills, have demanded the development of new technologies. Additionally, the lack of areas for waste disposal near to urban centers has led to vertical expansions of the existing sanitary landfills and, consequently, more rigorous stability analyses. Thus, the study of the mechanical behavior of the wastes becomes very important, especially, the shear strength. The present work aims to contribute to the understanding of the mechanical behavior of municipal solid wastes, through the construction of a large dimension direct shear equipment and the accomplishment of an experimental program to evaluate the shear strength of municipal solid wastes. The tests were carried out in samples with different initial conditions of composition, unit weight and moisture content, and age. Specific objectives of this work are to verify the Mohr-Coulomb failure criteria validity and to evaluate qualitatively the model proposed by Kolsch (1993 and 1995), which has shown to be more appropriate for municipal solid wastes. Besides the description of the developed equipment, the curves of shear stress versus horizontal displacement, strength envelopes and strength parameters variation with horizontal displacement are presented. The behavior of all the tested samples was characterized by a continuous strength gain without failure identification. The presence of fibrous materials led to a significant strength increase in relation to the samples without fibers. The strength parameters values (friction angle and cohesive intercept) were located inside the range presented in the literature. In respect to the Mohr-Coulomb envelope validity, it was verified that the samples with low fiber contents presented a linear failure criterion. The samples with high fiber contents presented a trend of a bi-linear failure criterion. The equipment developed and used in the tests and the used methodology shown to be appropriate.
Nos últimos anos, no Brasil e no exterior, em função de uma maior rigidez da legislação ambiental, o projeto e a operação de instalações seguras para a disposição de RSU, como os aterros sanitários, têm demandado o desenvolvimento de novas tecnologias. Aliado a isto, a escassez de grandes áreas próximas aos centros urbanos para disposição de RSU tem induzido o processo de verticalização dos aterros sanitários e, conseqüentemente, um maior rigor nas análises de estabilidade desses empreendimentos. Nota-se, desta forma, a importância de estudar o comportamento mecânico dos resíduos, em especial, a resistência ao cisalhamento. O presente trabalho tem como objetivo contribuir para o entendimento do comportamento mecânico dos resíduos sólidos urbanos, por meio da construção de um equipamento de cisalhamento direto de grandes dimensões e da realização de um programa experimental para avaliação da resistência dos resíduos sólidos urbanos. Os ensaios foram realizados em amostras com diferentes condições de composição, peso específico e umidade iniciais, e idade. Um dos objetivos específicos deste trabalho é verificar a validade do critério de ruptura de Mohr-Coulomb e avaliar qualitativamente a validade do modelo geotécnico proposto por Kolsch (1993 e 1995), o qual tem se mostrado mais apropriado para os resíduos sólidos urbanos. Além da descrição do equipamento desenvolvido, são apresentadas as curvas tensão cisalhante versus deslocamento horizontal, as envoltórias de resistência e a variação dos parâmetros de resistência com o deslocamento horizontal dos ensaios realizados. O comportamento de todas as amostras ensaiadas caracterizou-se por um contínuo ganho de resistência sem a identificação de ruptura. A presença de materiais fibrosos conferiu significativos ganhos de resistência, em relação às amostras sem fibras. Os valores dos parâmetros de resistência (ângulo de atrito e intercepto coesivo) situaram-se dentro da faixa apresentada na literatura. No que diz respeito à validade da envoltória de Mohr-Coulomb, constatou-se que as amostras cujas composições possuíam baixo percentual de materiais fibrosos apresentaram um critério de ruptura linear. Já as amostras cujas composições possuíam alto percentual de materiais fibrosos apresentaram uma tendência a um critério de ruptura bi-linear. O equipamento construído e utilizado nos ensaios e a metodologia empregada mostraram-se adequados.

The accomplishment of research concerning the urban solid waste characterization and sanitary landfills behavior is of great relevance, considering the importance and safety requirements of these structures. In this context, the present work aimed to investigate the influence of operational issues, mainly those concerning waste compaction, in the behavior of sanitary landfills. The study was carried out with the construction and monitoring of an Experimental Sanitary Landfill for urban solid wastes disposal, operating in real scale. The study also aimed at evaluating the mechanical behavior of the Experimental Sanitary Landfilland the evolution of the physical and chemical parameters of the leachate and gases generated, as well as evaluating the water balance and the performance of the landfill final cover. In general, the study demonstrated that the operational procedures influenced the behavior of Experimental Sanitary Landfill. The compaction study indicated that the compacted waste density is influenced directly by the inclination of the compaction slope and the number of passes of the compactor equipment. The lower densities were obtained with the small inclinations and numbers of the passes. In the same way larger densities were obtained with higher number of passes. It was also verified that the increase in waste densities were not significant when more passes of the equipments were used. The compressibility study evidenced the influence of the initial densities in the waste settlements. The observed difference between the results of the long term settlement models suggests that the modelsmust be used together, for the definition of settlement ranges. The evapotranspirative and capillary barriers final covers presented good performances, indicating the possibility of using alternative materials with lower costs. Concerning the water balance, the field data indicatedthe limitations of the conceptual model used and had confirmed a relationship between the precipitation and the level and content of leachate inside the landfill, as well as the discharges. The study of the leachate evolution, associated wiht the results of the gases monitoring,indicated that the landfill entered the methanogenic phase one hundred days after the end of the waste disposal. The study indicated the influence of the precipitation in the evolution of the physical and chemical leachate parameters, suggesting the importance of the accomplishment of the analysis of the behavior of these parameters in terms of bothconcentration and effluent load.
A realização de pesquisas e estudos relacionados à caracterização dos resíduos sólidos urbanos e ao entendimento do comportamento de aterros sanitários é de grande relevância, dada a importância e a segurança que estas obras exigem. Neste contexto, o presente trabalho objetivou investigar a influência de variáveis operacionais, principalmente as relacionadas à compactação dos resíduos, no comportamento de aterros sanitários. O estudo foi realizado a partir da implantação e monitoramento de um Aterro Sanitário Experimental para disposição de resíduos sólidos urbanos, operando em escala real. O estudo teve ainda como objetivos, avaliar o comportamento mecânico do Aterro Sanitário Experimental e a evolução temporal dos parâmetros físico-químico dos líquidos lixiviados e gases gerados, assim como avaliar o balanço hídrico e o desempenho das camadas de cobertura final. De maneira geral, o estudo demonstrou que os procedimentos operacionais influenciaram o comportamento do Aterro Sanitário Experimental. O estudo da compactação indicou que a peso específico dos resíduos compactados é influenciada diretamente pela inclinação da rampa de compactação e pelo número de passadas do equipamento compactador. Os maiores pesos específico foram obtidos com as menores inclinações e menores números de passadas. Da mesma forma pesos específicos maiores foram obtidos com um número maior de passadas. Verificou-se ainda que para um número mais elevado de passadas, o ganho em termos de peso específico é pequeno. O estudo da compressibilidade evidenciou a influência dos pesos específicos iniciais nos recalques. A diferença observada entre os resultados dos modelos de previsão de recalques sugere que os mesmos devam ser utilizados de forma conjunta, para a definição de faixas de recalques. As camadas de cobertura final do tipo evapotranspirativa e barreira capilar apresentaram desempenho adequado, indicando a possibilidade de utilização de materiais alternativos e de menor custo. Em relação ao balanço hídrico, os dados de campo indicaram as limitações do modelo conceitual utilizado e confirmaram uma relação entre a precipitação pluviométrica e o nível e volume de líquidos lixiviados no interior do aterro e as vazões. O estudo da evolução temporal dos líquidos lixiviados, associado ao monitoramento de gases, indicou que o aterro entrou na fase metanogênica cem dias após o final da aterragem. O estudo indicou a influência da precipitação pluviométrica na evolução dos parâmetros físicoquímicos dos líquidos lixiviados e mostrou a importância da realização da análise do comportamento desses parâmetros tanto em termos de concentração quanto da carga efluente.

A trend toward verticalization of sanitary landfills, especially in large cities, has been increasing, as well as the number of geotechnical accidents observed. These accidents can occur by natural causes, but in most cases they are related to inadequate design, absence or inefficiency of liquids and gases drainage systems, construction and operating problems and inexistence of environmental and geotechnical monitoring programs, which could help identifying unexpected behaviors. There are many papers describing geotechnical accidents in landfills, but reports of periodic inspections or the existence of emergency and contingency plans are hardly found. Different models of environmental, geotechnical and operational monitoring of landfills are expected and necessary, due to the particular characteristics of each project and site. Although literature presents a large number of works on inspections, risk assessments, emergency and contingency plans for industries and dams, the application of these concepts to landfills is still incipient. This work aims to identify the best practices for geotechnical monitoring of landfills and develop guidelines for inspection and emergency actions that can help to technicians and operators of landfills to design, operate, monitor, inspect and keep track in extreme situations. The Delphi methodology was used and questionnaires were sent to a group of experts, formed by researchers, consultants and operators of landfills. The questionnaire addressed the phases of a landfill and the parameters, methods and procedures related to them, asking respondents to indicate the importance of each item to medium and large landfills, in the current situation and the best practice that could be recommended. The results were statistically analyzed and after two rounds the consensus of opinion was reached. The results allowed drawing a diagnosis of the current situation regarding studies, projects and monitoring of medium and large landfills. Based on the results of the questionnaires analysis, guidelines for carrying out geotechnical monitoring programs and developing emergency and contingency plans of these projects were proposed.
A tendência à verticalização dos aterros sanitários, principalmente nos grandes centros urbanos, tem sido cada vez mais frequente e como consequência tem-se observado um número crescente de acidentes geotécnicos. Estes acidentes podem ocorrer por causas naturais, mas, na maioria das vezes as causas estão relacionadas a projetos inadequados, ausência ou ineficiência de sistemas de drenagem de líquidos e gases, problemas construtivos e operacionais e inexistência de programas de monitoramento ambiental e geotécnico, que poderiam ajudar na identificação de comportamentos não esperados. Existem diversos trabalhos publicados sobre acidentes geotécnicos ocorridos em aterros sanitários, mas dificilmente são encontrados relatos sobre inspeções periódicas ou a existência de planos de contingência ou de emergência. As variações de modelos de monitoramento ambiental, geotécnico e operacional em aterros sanitários são esperadas e necessárias devido às características particulares de cada empreendimento. Embora a literatura apresente inúmeros trabalhos sobre inspeções, análises de risco, planos de contingência e de ações emergenciais em indústrias e barragens, a aplicação desses conceitos aos aterros sanitários ainda é incipiente. Este trabalho tem como objetivo identificar as melhores técnicas de monitoramento geotécnico e desenvolver diretrizes para inspeção e ações emergenciais que possam ajudar aos técnicos e operadores de aterros sanitários a projetar, operar, monitorar, inspecionar e manter o controle em situações extremas. Utilizou-se a metodologia Delphi, com envio de questionários a um conjunto de especialistas, formado por pesquisadores, consultores e operadores de aterros sanitários. O questionário abordava as diversas fases de um aterro sanitário e os parâmetros, métodos e procedimentos relacionados às fases, solicitando aos respondentes a indicação da importância de cada item para aterros de médio e grande porte, na situação atual e a melhor prática que poderia ser recomendada. Os resultados foram tratados estatisticamente, tendo sido necessárias duas rodadas para que o consenso das opiniões fosse alcançado. Os resultados permitiram traçar um diagnóstico da situação atual referente aos estudos, projetos e monitoramento de aterros sanitários de médio e de grande porte. Com base nos resultados da análise dos questionários foram propostas diretrizes para a realização de monitoramento geotécnico e para a elaboração de planos de contingência e emergência nesses empreendimentos.

Nella presente Tesi è affrontata l’analisi sperimentale e teorica del comportamento di pareti in muratura rinforzate con FRCM e sollecitate da azioni di taglio fuori piano. Lo schema statico adottato per i campioni sperimentati consiste in uno schema appoggio-appoggio, mentre le forze esterne di taglio sono state applicate secondo uno schema di carico a quattro punti. Durante il corso della prova, i pannelli murari sono inoltre stati soggetti ad un carico di precompressione verticale costante, che simula l’effetto della presenza del solaio in un edificio in muratura. Dopo una descrizione teorica delle principali caratteristiche dei materiali compositi e dei loro costituenti, all’interno della Tesi sono richiamati alcuni studi scientifici relativi al comportamento fuori piano di elementi strutturali rinforzati con FRCM. In seguito vengono presentati i materiali impiegati per la campagna sperimentale e le prove di caratterizzazione meccanica eseguite. Vengono poi riportati i risultati sperimentali delle prove a taglio fuori piano in termini di spostamenti, di deformazioni e di scorrimenti, affrontando infine un confronto tra i risultati ottenuti per i campioni esaminati e riportando alcune considerazioni circa la strumentazione impiegata. L’ultima parte della Tesi è dedicata all’analisi teorica delle pareti. Viene proposto un modello teorico per stimare la resistenza fornita dai muri rinforzati, ipotizzando tre possibili modalità di rottura: rottura a trazione della fibra, rottura per distacco tra FRCM e supporto in muratura e rottura per delaminazione interna. Infine, viene riportata la modellazione agli elementi finiti svolta mediante il codice di calcolo MidasFea, che consente di attribuire ai materiali legami costitutivi adeguati per la modellazione di strutture in muratura, cogliendone il comportamento non lineare e il progressivo danneggiamento.

Interventions for strengthening, repairing, and upgrading of existing reinforced concrete (RC) structures are aimed to increase/restore their structural capacity to withstand flexural, shear, torsional, and axial loads. Reasons to carry out such interventions vary from the need to upgrade the structure to current guidelines, overcome design and construction mistakes, and allow an increment in load due to a change in use. In addition, unexpected overloading events, such as earthquakes, might damage the structure, reducing its original performance. The same behavior can be expected in the case of fire or lack of adequate maintenance. In the previous decades the use of fiber reinforced polymer (FRP) composites has gained worldwide popularity to carry out such interventions due to some of their properties such as high strength-to-weight ratio, ease of application, and good corrosion resistance. However, the use of organic resin matrix in FRP composites has been associated with some limitations of their use such as inability to apply onto wet surfaces, low resistance to relatively high temperatures, and difficulty to carry out post-earthquake assessment. For this reason, in recent years, an important research effort has been developed in order to study composites known as fiber reinforced cementitious matrix (FRCM) composites, in which the organic resin is replaced by an inorganic matrix. In this thesis, the behavior of RC beams strengthened in shear with externally bonded FRCM composites is studied. The first part of this thesis summarizes the state of research on the topic of shear strengthening of RC beams using externally bonded FRCM composites with the goal of serving as a reference point for the development of future research. A detailed bibliographical review of the literature on the shear strengthening of RC beams using FRCM composites is carried out, and the major findings and main aspects that should be addressed in future research are indicated. The collected experimental evidence shows that FRCM composites are able to increase the shear strength of RC beams, modifying in some cases the type of failure from shear to a flexural mode. Then, the results of an experimental campaign on shear strengthening of RC beams with externally bonded FRP and FRCM composites are presented. FRP and FRCM composites with two different fiber types are examined. Two different stirrup spacings were employed to investigate the internal-external shear reinforcement interaction. Considering the limited experimental evidence on the use of anchors for RC beams strengthened in shear with FRCM composites, the performance of FRCM strengthened beams with and without anchors is also compared. Results show that the effectiveness of the FRCM system depends on the spacing of theinternal shear reinforcement. In addition, internal-external shear reinforcement interaction was witnessed, but the intereaction appears to be less pronounced than in beams strengthened with FRP composites. Design models proposed to predict the contribution of the FRCM composite to the shear strength of RC beams are assessed using the database of experimental results collected and compiled by the author and the experimental results included in this thesis. Results show that the performance of the models is highly influenced by the type of failure mode attained by the strengthened beams. In addition, the use of the FRCM composite properties instead of the bare fiber mechanical characteristics does not result in an increase in the accuracy of the models. Strains measured by strain gauges mounted onto the internal (stirrups) and external (FRCM system) transverse reinforcement of the tested beams are used to compute the individual contributions of the concrete, steel, and fibers to the overall shear strength of the FRCM strengthened beams, and to study the possible interaction among them. It was found that the concrete contribution to the shear resistance starts to decrease after first cracking of the concrete is achieved. After this point, the stirrup and fiber contributions start to increase until the peak load is attained. Lastly, a new analytical model based on the bond behavior of the FRCM composites applied onto concrete substrates is introduced and discussed. Although additional tests are required to calibrate the model, initial results show that the assumptions and hypothesis used during its development are appropriate.
Gli interventi per il rafforzamento e la riparazione delle strutture esistenti in calcestruzzo armato mirano ad aumentare e ripristinare la loro capacità strutturale per resistere a carichi flessionali, a taglio, torsionali e assiali. I motivi per fare tali interventi variano dalla necessità di aggiornare la struttura alle linee guida attuali, superare gli errori di progettazione e costruzione e consentire un incremento del carico a causa di un cambiamento nell'uso. Inoltre, eventi di sovraccarico inaspettati, come terremoti, potrebbero danneggiare la struttura, riducendo le prestazioni originali. Lo stesso comportamento può essere previsto in caso d’incendio o mancanza di manutenzione adeguata. Nei decenni precedenti l'uso di compositi polimerici rinforzati con fibre (FRP) ha guadagnato popolarità in tutto il mondo per fare tali interventi a causa di alcune delle loro proprietà come il rapporto tra forza-peso, facilità di applicazione e buona resistenza alla corrosione. Tuttavia, l'uso della matrice di resina organica dei compositi FRP è stato associato ad alcune limitazioni del loro uso, come l'incapacità di applicare su superfici bagnate, bassa resistenza a temperature relativamente alte e difficoltà nella valutazione post-terremoto. Per questo motivo, negli ultimi anni, è stato sviluppato un importante sforzo di ricerca per lo studio di compositi noti come compositi a matrice cementizia fibrorinforzata (FRCM), in cui la resina organica viene sostituita da una matrice inorganica. In questa tesi, è studiato il comportamento de travi di calcestruzo armato rafforzate a taglio con compositi FRCM. La prima parte di questa tesi riassume lo stato della ricerca sul tema del rinforzo a taglio delle travi RC utilizzando compositi FRCM con legami esterni con l'obiettivo di servire come punto di riferimento per lo sviluppo della ricerca futura. Viene effettuata una revisione bibliografica dettagliata della letteratura sul rafforzamento a taglio delle travi utilizzando i compositi FRCM, e vengono indicati i principali risultati e gli aspetti principali che dovrebbero essere affrontati nelle ricerche future. Le prove sperimentali raccolte mostrano che i compositi FRCM sono in grado di aumentare la resistenza al taglio delle travi, modificando in alcuni casi il tipo di cedimento da taglio a una modalità a flessione. Quindi, sono presentati i risultati di una campagna sperimentale sul rinforzo a taglio di travi con compositi FRP e FRCM. Vengono esaminati i compositi FRP e FRCM con due diversi tipi di fibre. Sono state impiegate due diverse spaziature delle staffe per studiare l'interazione di rinforzo di taglio interno-esterno. Considerando le limitate prove sperimentali sull'uso di elementi di ancoraggio travi rinforzate a taglio con materiali compositi FRCM, viene anche confrontata la prestazione di travi rinforzate FRCM con e senza ancoraggi. I risultati mostrano che l'efficacia del sistema FRCM dipende dalla spaziatura del rinforzo del taglio interno. Inoltre, è stata osservata l'interazione di rinforzo di taglio interno-esterno, ma l'interazione sembra essere meno pronunciata rispetto alle travi rinforzate con compositi FRP. I modelli di progettazione proposti per prevedere il contributo del composito FRCM alla resistenza al taglio delle travi sono valutati utilizzando il database dei risultati sperimentali raccolti e compilati dall'autore e i risultati sperimentali inclusi in questa tesi. I risultati mostrano che le prestazioni dei modelli sono fortemente influenzate dal tipo di modalità di rottura raggiunta. Inoltre, l'uso delle proprietà dei compositi FRCM al posto delle caratteristiche meccaniche delle fibre non comporta un aumento dell'accuratezza dei modelli. Le deformazioni misurati dagli estensimetri montati sulle armature interne (staffe) e esterne (sistema FRCM) delle travi sottoposte a prova vengono utilizzati per calcolare i singoli contributi del calcestruzzo, dell'acciaio e delle fibre alla resistenza complessiva al taglio delle travi rinforzate con i compositi FRCM, e per studiare la possibile interazione tra loro. Si è costatato che il contributo concreto alla resistenza al taglio inizia a diminuire dopo il primo crollo del calcestruzzo. Dopo questo punto, i contributi della staffa e della fibra iniziano ad aumentare fino al raggiungimento del picco di carico. Infine, è introdotto e discusso un nuovo modello analitico basato sul comportamento del legame dei compositi FRCM applicati su substrati in calcestruzzo. Sebbene siano necessari successivi test per calibrare il modello, i risultati iniziali mostrano che le ipotesi utilizzate durante il suo sviluppo sono appropriate.

In the last years, due to many severe seismic events, it becomes more and more important to understand the structural performance of masonry structures subjected to seismic actions and structural reinforce became an important task in civil engineering. The developments of innovative techniques for structural retrofitting represent a great change in order to reduce the seismic vulnerability of masonry buildings. Beside the traditional reinforce techniques, new reinforce born such as Fiber Reinforced Polymer (FRP) and Fiber Reinforced Cementitious Matrix (FRCM) The aim of this thesis is to study the shear strength of masonry panels, subjected to in-plane actions, reinforced with FRCM.

Nella tesi viene trattato il recupero delle strutture murarie tramite l’utilizzo di materiali compositi, in particolare si trattano i Fyber Reinforced Polymers (FRP) e i Fybers Reinforced Cementitious Matrix (FRCM). Ad oggi le principali tecniche di consolidamento si basano sull’utilizzo di materiali “classici”, come acciaio o cemento armato, dei quali esistono dettagliate indicazioni progettuali, ma che presentano la controindicazione di essere invasive e, quindi, di modificare il comportamento statico del sistema a cui vengono applicate. Utilizzando materiali compositi, invece, si possono ottenere importanti miglioramenti senza apportare cambiamenti statici, con l’ulteriore vantaggio di poter essere nascosti da intonaci. Prendendo come riferimento le normative in via di costituzione per la progettazione di interventi con FRCM, si sottolineano le principali differenze in termini di metodologie di verifica e di risultati tra i due materiali di interesse. L'obiettivo è quello suggerire delle indicazioni di riferimento utili al momento della selezione di un composito anziché l’altro. Si dimostra che è possibile realizzare interventi migliorativi sulla muratura con entrambi i materiali citati: a seconda della situazione risulteranno differenti le formule di verifica e gli ambiti in cui un composito è più indicato. Grazie alle caratteristiche di traspirabilità e permeabilità al vapore, oltre alla flessibilità che permette modeste deformazioni del supporto, i compositi FRCM sono particolarmente indicati all’applicazione su apparati murari. Tuttavia, non tutti i meccanismi di collasso possono essere recuperati equivalentemente con ambo i materiali, principalmente perché gli interventi con FRCM richiedono una maggiore superficie di applicazione.

La corrosion des armatures en acier est l'un des mécanismes les plus destructifs pour les structures en béton armé. La corrosion nuit non seulement à l'intégrité structurale et à l’aptitude au service de la structure endommagée, mais peut aussi entraîner des défaillances inattendues ou des ruptures fragiles. Malgré les dispositions rigoureuses de la plupart des codes de pratique pour éviter la corrosion, des signes de dommages dus à la corrosion sont toujours signalés. Récemment, des systèmes à matrice cimentaire renforcée de fibre (MCRF) ont été proposés comme une technique innovante de renforcement/réparation pour les structures en béton afin de surmonter les inconvénients associés à l'utilisation des systèmes de polymères renforcés de fibres (PRF). Bien que l'utilisation de composites MCRF pour renforcer les éléments en béton non endommagés ait prouvé son efficacité, très peu est connu sur la viabilité de leur utilisation pour renforcer les éléments en béton endommagés à divers niveaux dus à la corrosion. De plus, les comportements de post-réparation et la durabilité à long-terme des éléments corrodés et renforcés par les systèmes MCRF et qui seront probablement exposés aux mêmes conditions environnementales qui prévalaient avant leur réparation, n'ont pas retenu l'attention des chercheurs dans la littérature. De plus, la plupart de nos infrastructures, telles que les ponts et garages de stationnement, sont susceptibles d'être endommagées par la corrosion tout en étant soumises à des charges oscillatoires qui provoquent de la fatigue. À ce jour, aucune information n'est disponible sur l'effet de la combinaison de la charge de fatigue et de la corrosion dans les structures renforcées par les systèmes MCRF. Dans ce travail, les comportements monotones et de fatigue en flexion des poutres en béton endommagées par la corrosion et renforcées par des systèmes MCRF ont été étudiés en plus de leur performance à long-terme, c'est-à-dire après une exposition à un environnement corrosif après leur renforcement. Le travail comprend des investigations expérimentales et numériques. Les prédictions analytiques et les formulations théoriques actuellement disponibles dans les codes de conception ont été aussi vérifiées par rapport aux résultats expérimentaux. Le programme expérimental consistait à tester trente (30) poutres en béton à grande échelle de 150 × 250 × 2800 mm. Les poutres ont été construites et testées en configuration de charge à quatre points. Un processus accéléré de corrosion a été utilisé pour corroder les armatures d'acier en traction dans le tiers central des poutres. Les paramètres d'essai comprenaient le niveau de corrosion (représenté par 10, 20 et 30% de perte de masse dans l'acier de traction), le type de système de renforcement utilisé (Polyparaphénylène benzobisoxazole (PBO-MCRF), MCRF de carbone et PRF), la quantité de composites MCRF (1, 2, 3 et 4 couches), le schéma de renforcement MCRF (couches ancrées aux extrémités par rapport aux couches continues sous forme U) et le régime de chargement (monotone et fatigue). Les résultats des tests ont montré que l'utilisation de composites MCRF améliorait significativement le comportement en flexion des poutres corrodées. Les composites MCRF ont contrôlé le mode de défaillance des poutres renforcées plutôt que le niveau de corrosion des barres d'acier. Les poutres renforcées par la MCRF ont montré une augmentation de leurs résistances ultimes variant entre 7 et 65% de celles des poutres vierges (poutres ni corrodées ni renforcées) en fonction du type, de la quantité et du schéma de la MCRF utilisée. L'exposition des poutres réparées par la MCRF à d’autres cycles de corrosion a entraîné une réduction de 23% de la perte de masse de l'acier. Le schéma en U était plus efficace que le schéma d'ancrage aux extrémités à retarder le délaminage des couches de MCRF dans les poutres renforcées et testées à court terme. Il a également atténué l'effet des fissures de corrosion longitudinales et, par conséquent, a augmenté l'efficacité du renforcement MCRF. Les essais de fatigue ont montré que la corrosion des barres d'acier diminuait considérablement la résistance à la fatigue des poutres non renforcées. Le renforcement avec des composites MCRF a augmenté la durée de vie en fatigue des poutres endommagées par la corrosion de 38 à 377% de celle des poutres corrodées non-renforcées. Cependant, le renforcement par MCRF n'a pas restauré la durée de vie en fatigue des poutres vierges. Dans l'étude numérique réalisée dans ce travail, des modèles d'éléments finis (ÉF) tridimensionnels (3D) ont été développés pour simuler le comportement non linéaire des poutres corrodées et renforcées par des composites MCRF et PRF à l'aide du progiciel ATENA-3D. Les résultats de l'analyse numérique étaient en bon accord avec ceux obtenus expérimentalement en termes de modes de défaillance, de déformations, de capacités de charge et de flèches. Les modèles ÉF développés ont été capables de capturer le comportement non-linéaire des poutres testées avec une bonne précision. Une étude paramétrique a ensuite été menée pour étudier l'effet de la résistance à la compression du béton et de l'épaisseur de recouvrement des armatures sur l'efficacité de renforcement des systèmes composites. Il a été observé que la rupture des poutres renforcées par des FRCM était indépendante de la résistance à la compression du béton ou de l'épaisseur de de recouvrement et était régie uniquement par le glissement du tissu dans la matrice. Sur le plan analytique, les équations de conception de l’ACI-549.4R-13 (ACI 2013) ont été évaluées à l'aide des données expérimentales obtenues à partir des tests. Il a été conclu que les formulations théoriques de l’ACI-549.4R-13 peuvent raisonnablement prédire les résistances ultimes des poutres renforcées ancrées à l'extrémité mais sous-estimer celles des poutres ancrées en continu sous forme U. Un facteur de schéma de 1,1 a ensuite été proposé pour calculer la résistance nominale des poutres renforcées par MCRF sous forme U. Le résultat de ce travail a été publié (ou soumis pour publication) dans cinq articles de revues et cinq conférences, comme détaillé tout au long de la thèse.
Corrosion of steel reinforcement is one of the most destructive mechanisms for reinforced concrete (RC) structures. Corrosion not only impairs the structural integrity and the serviceability of the damaged structure, but it may also lead to unexpected and brittle failures. Despite the rigorous provisions of most codes of practice to avoid corrosion, evidences of corrosion damage are still being reported. Recently, fabric-reinforced cementitious matrix (FRCM) systems were proposed as an innovative strengthening/repair technique for RC structures to overcome the drawbacks associated with the use of the well-documented fiber-reinforced polymer (FRP) systems. While the use of FRCM composites to strengthen un-damaged RC members has proven its efficiency, very little is known about the viability of their use to retrofit RC members with various levels of corrosion damage. In addition, the post-repair performance and the long-term durability of the FRCM-strengthened corroded members, which most likely will be exposed to the same environmental conditions that have prevailed prior their repair, have not received attention in the literature. Moreover, most of our infrastructures such as bridges and parking garages are susceptible to corrosion damage while continuously being subjected to oscillatory loads that cause fatigue. To date, no information is available about the effect of combining fatigue loading with corrosion in FRCM-strengthened structures. In this work, the monotonic and fatigue flexural behaviors of corrosion-damaged RC beams strengthened with FRCM systems were investigated in addition to their long-term performance, i.e. after further exposure to corrosive environment following their strengthening. The work includes experimental and numerical investigations. The analytical predictions and theoretical formulations that are currently available in the design codes have been verified against the experimental results. The experimental program consisted of testing thirty (30) large-scale RC beams of 150×250×2800 mm. The beams were constructed and tested under four-point load configuration. An accelerated corrosion process was utilized to corrode the bottom steel reinforcement in the middle third of the test specimens. The test parameters included the level of corrosion damage (represented by 10, 20, and 30% mass loss in the tensile steel), the type of the strengthening system used (Polyparaphenylene benzobisoxazole (PBO-FRCM), C-FRCM, and FRP), the amount of FRCM composites (1, 2, 3, and 4 layers), the FRCM strengthening Scheme (end-anchored versus continuously wrapped layers), and the loading regime (monotonic and fatigue). The test results showed that the use of FRCM composites significantly enhanced the flexural behavior of the corroded beams. FRCM governed the failure mode of the strengthened beams rather than the level of corrosion damage of the steel bars. FRCM-strengthened beams showed an increase in their ultimate strengths that ranged between 7 and 65% of that of the virgin (neither corroded nor strengthened) beam based on the type, amount, and Scheme of the FRCM used. Exposing the repaired beams to post-repair corrosion resulted in 23% reduction in the steel mass loss. The U-wrapped scheme was more efficient than the end-anchoring scheme in delaying the delamination of the FRCM plies in the short-term repaired beams. It also mitigated the effect of the longitudinal corrosion cracks and consequently increased the post-repair strengthening effectiveness of FRCM systems. Fatigue tests showed that corrosion of steel bars dramatically decreased the fatigue life of the unstrengthened-beams. Strengthening with FRCM composites increased the fatigue life of the corrosion-damaged beams by 38 to 377% of that of the corroded-unstrengthened beams. However, FRCM strengthening did not restore the fatigue life of the virgin beams. In the numerical study carried out in this work, three-dimensional finite element (FE) models were developed to simulate the nonlinear behavior of the corroded beams strengthened with FRCM and FRP composites using the software package ATENA-3D. The results of the numerical analysis were in good agreement with those obtained experimentally in terms of failure modes, strains, load-carrying capacities, and deflections. The developed FE models were able to capture the non-linear behavior of the tested beams with good accuracy. A parametric study was then conducted to investigate the effect of concrete compressive strength and thickness of concrete cover on the strengthening effectiveness of the composite systems. It was observed that failure of RCM-strengthened beams was independent of the compressive strength of concrete or the thickness of the concrete cover and was governed only by fabric slippage within the matrix. Analytically, the design equations of ACI-549.4R-13 (ACI 2013) were assessed using the experimental data obtained from the tests. It was concluded that the theoretical formulations of CI-549.4R-13 can reasonably predict the ultimate strengths of the end-anchored strengthened beams but underestimated those of continuously-anchored beams. A scheme factor of 1.1 was then proposed to calculate the nominal strength of beams strengthened with continuously-wrapped shape of FRCM. The outcome of this work has been published (or submitted for publication) in five journal articles and five conferences, as detailed throughout the thesis.

The increasing use of Fiber Reinforced methods for strengthening existing brick masonry walls and columns, especially for the rehabilitation of historical buildings, has generated considerable research interest in understanding the failure mechanism in such systems. This dissertation is aimed to provide a basic understanding of the behavior of solid brick masonry walls unwrapped and wrapped with Fiber Reinforced Cementitious Matrix Composites. This is a new type of composite material, commonly known as FRCM, featuring a cementitious inorganic matrix (binder) instead of the more common epoxy one. The influence of the FRCM-reinforcement on the load-carrying capacity and strain distribution during compression test will be investigated using a full-field optical technique known as Digital Image Correlation. Compression test were carried on 6 clay bricks columns and on 7 clay brick walls in three different configuration, casted using bricks scaled respect the first one with a ratio 1:2, in order to determinate the effects of FRCM reinforcement. The goal of the experimental program is to understand how the behavior of brick masonry will be improved by the FRCM-wrapping. The results indicate that there is an arching action zone represented in the form of a parabola with a varying shape according to the used configuration. The area under the parabolas is considered as ineffectively confined. The effectively confined area is assumed to occur within the region where the arching action had been fully developed.

In the process of crushing concrete waste, significant amounts of fine by-products, the so called fine recycled concrete aggregates (FRCA), are generated and excluded from potential use. Limited research has thoroughly investigated the performance of concrete mixes with FRCA, very likely due to the complexity in analysing non-negligible amounts of adhered residual cement paste (RCP). Although some studies have proposed promising sustainable mix-design procedures accounting for the different microstructure when using coarse recycled concrete aggregates (CRCA), no similar approach exists for FRCA concrete. In this work, two promising procedures for mix-designing eco-efficient concrete with 100% FRCA are proposed accounting for the presence of RCP to reduce cement content in new mixtures. First, built on top of the existing procedure for CRCA mix-design, modifications to the Equivalent Volume (EV) method were introduced toconsider full replacement of fine natural sand by FRCA. Second, based on the concept of continuous Particle Packing Models (PPM), an optimized procedure was proposed to allow maximum packing density of FRCA mix linked to a given level of measured RCP content. Results verified the feasibility of producing eco-efficient concrete mixes with 100% FRCA, emphasizing the PPM mixes to report superior rheological and mechanical performance along with suitable durability-related properties. Yet, results also indicated the influence of simple or multistage crushed FRCA on the overall performance of mixes.

Le tipologie di prova adottate durante i test condotti su campioni FRCM sono state essenzialmente due: prove di trazione e prove di aderenza, svolte impiegando due diverse modalità di applicazione del carico (caricamento monotono e/o ciclico) e due diverse tipologie di rinforzo (una in fibra di carbonio e una in fibra di vetro). Nel corso delle prove di trazione, i risultati migliori sono stati ottenuti per i rinforzi in fibra di carbonio con applicazione del carico di trazione monotona, quindi per la soluzione in cui si è utilizzata la fibra avente le caratteristiche meccaniche migliori; il comportamento di questi materiali è risultato tuttavia peculiare, in quanto lo strato di malta esterno ha mostrato spesso distacchi e perdita di adesione rispetto alla rete bidirezionale di rinforzo, rendendo difficoltosa la misura esterna della deformazione del composito. I rinforzi in fibra di vetro (GFRCM) hanno mostrato risultati inferiori in termini di tensione massima, in accordo con la tipologia di fibra impiegata, ma hanno evidenziato un comportamento caratterizzato si dall’apertura di fessure, ma maggiormente assimilabile ad una schematizzazione trilineare, senza fenomeni evidenti di distacco esterno della matrice prima della rottura. Dalla sperimentazione dei provini mediante prove di aderenza è emerso che, sia nel caso di prove monotone che cicliche, i provini rinforzati con GFRCM hanno mostrato un’efficienza maggiore. La rete in fibra di vetro ha mostrato una aderenza migliore all’interno della matrice cementizia, rispetto alla rete in fibra di carbonio, perché presenta uno speciale trattamento superficiale (appretto) che ne migliora la compatibilità e l’adesione al supporto. I rinforzi GFRCM testati hanno sfruttato al meglio le proprie caratteristiche meccaniche raggiungendo valori di carico maggiori (circa doppi) rispetto ai rinforzi CFRCM.

Concrete technology has changed greatly in the past decades. Steel fibre reinforced concrete (SFRC) is an example of the development in this field. It is obtained by adding fibres that act as a reinforcement of the cement matrix, improving the tenacity, cracking control and durability of the concrete members. In certain applications, SFRC has become an alternative material to concrete reinforced with conventional steel rebar. Despite of numerous advantages of SFRC, problems and uncertainties still exist regarding the design, the characterization and the performance of this material. Furthermore, the structural design and the properties of SFRC in real-scale elements as well as the fibre distribution are not properly clarified. All these issues need to be addressed in order to promote the safe and efficient use of the material. The objective of this doctoral thesis is to develop a systematic and innovative approach for the design optimization and characterisation of FRC precast segment. In total, 4 subjects are covered: a critical study related to the design of FRC precast segment considering the ductility requirements of the Model Code 2010; the experimental and analytical study of concrete blocks subjected to concentrated loads; the design procedure and experimental research on FRC precast segment for shafts and the anisotropy of the FRC precast segment. The first subject presents an analysis of the technical requirements demanded by the Model Code 2010 when steel fibres are the only reinforcement for concrete elements. According to this revision, an alternative approach according to the Model Code 2010 which is more compatible with the requirements of the application in tunnels is proposed. This approach may lead to the reduction of the fibre content required to guarantee a minimum ductility of the element. In order to evaluate the repercussion of the ductility criteria in terms of fibre consumption, a case study of Metro L9 of Barcelona is presented. The second subject contributes to the understanding about the behaviour of concrete blocks subjected to concentrated load. An experimental programme is performed to evaluate the influence of the height-to-length ratios in the mechanical response of the blocks. Based on the observations derived, a strut-and-tie model is adopted to assess the value of the loads Fcr and Fmax for short blocks and long blocks. A case study of Metro Line 9 in Barcelona is conducted, and the results of the study indicates that with an appropriate safety factors for the SLS and the ULS, no traditional reinforcement is required to resist the tensile stresses due to the concentrated loads applied by the jacks of the tunnel boring machine. The third subject is to verify that it is viable to replace the traditional reinforcement with steel fibres in the segmental lining ring of shaft constructed with vertical shaft machine. An analytical formulation based on MC 2010 is proposed to evaluate the minimum requirements the FRC must fulfil to carry out this replacement. Likewise, an experimental campaign was performed to characterize the mechanical behaviour of both conventional and self-compacting concrete reinforced with fibre content (Cf) between 30 and 60 kg/m3. Posteriorly, another full-scale experimental campaign of bending test on segments is performed to verify the ductile behaviour of two types of segments under failure scenario. These results are used to validate the proposed formula. The last subject focuses on the study of the anisotropy in terms of fibre distribution and local mechanical response of segments with conventional and self-compacting SFRC. For that, a large number of cores extracted from real-scale segments are tested for the fibre distribution with the inductive method and, then, for the mechanical response with the Barcelona test. A conceptual model for the fibre orientation is proposed based on the average values obtained from the tests.
La tecnología del hormigón ha avanzado notablemente en las últimas décadas. En este sentido, el hormigón reforzado con fibras (HRF) es un ejemplo del desarrollo en este campo. Este se obtiene mediante la adición de fibras que actúan como un refuerzo de la matriz de cemento, mejorando la tenacidad y el control de la figuración y, por ende, la durabilidad. En ciertas aplicaciones, HRF se ha convertido en un material alternativo para hormigón armado convencional. A pesar de las numerosas ventajas asociadas al uso del HRF, todavía existen incertidumbres en cuanto al diseño, la caracterización y el desempeño mecánico de este material. En particular, es necesario desarrollar adecuadamente el concepto y requerimiento de ductilidad de las estructuras de HRF así como integrar de forma fidedigna aspectos de orientación y de distribución de fibras en el diseño. Todas estas cuestiones deben abordarse con el fin de promover el uso seguro y eficiente del material. El objetivo de esta tesis doctoral es el desarrollo de un enfoque sistemático e innovador para el diseño y caracterización de dovelas de HRF para la ejecución de revestimiento de túneles. En total, esta tesis se cubren 4 aspectos: un estudio crítico en relación con el diseño del dovelas de HRF teniendo en cuenta los requisitos de ductilidad del Código Modelo 2010; un estudio experimental y analítico de bloques de hormigón sometidas a cargas concentradas; el pre ¿ diseño de dovelas para la ejecución de pozos verticales y el análisis de anisotropía en la distribución y orientación de fibras.En el primer tema se aborda un análisis de los requisitos técnicos exigidos por el Código Modelo de 2010 en estructuras de HRF en las que las fibras son los únicos elementos de refuerzo del hormigón. De acuerdo con esta revisión, se propone un enfoque alternativo y compatible con el MC 2010 más alineado con lo requerimiento estructurales y necesidades resistentes de las dovelas de HRF. Este enfoque conduce a la optimización del contenido de fibra necesaria para garantizar la ductilidad adecuada para estos elementos estructurales. Con el fin de evaluar la repercusión de los criterios de ductilidad en términos de consumo de fibra, se presenta un estudio de caso de Metro L9 de Barcelona.El segundo campo de investigación tratado contribuye al conocimiento en relación al comportamiento de elementos de hormigón sometidos a cargas concentradas. En este sentido, se ha llevado a cabo una campaña experimental para evaluar la influencia del ratio altura ¿ ancho en el mecanismo de rotura de los bloques ensayados. En base a las observaciones, se ha planteado un modelo de bielas y tirantes para evaluar las cargas de figuración y de rotura de los bloques. La formulación propuesta se ha empleado para evaluar dichas cargas en el caso de empuje de los gatos de las dovelas diseñadas para los túneles de la Línea 9 del Metro de Barcelona. Los resultados ponen de manifiesto que, empleando los coeficientes de seguridad adecuados, no se requiere armadura pasiva adicional para resistir los esfuerzos de tracción que se generan en la fase de empuje de los gatos, en el caso particular estudiado. Por último, en la cuarta línea de investigación se estudia en profundidad a nivel experimental la anisotropía de la distribución, cuantía y orientación de las fibras en dovelas de hormigón convencional y de hormigón autocompactante reforzadas con fibras. Para ello, se extrajeron un número elevado y representativo de testigos de las dovelas a escala real fabricadas. Se emplearon métodos no destructivos tipo inductivo para evaluar la cuantía y orientación de las fibras. Asimismo, se empleó el ensayo Barcelona (ensayo destructivo) para evaluar también ambas variables así como la resistencia a tracción residual de los hormigones. En base a los resultados se propone un modelo conceptual para estimar la orientación de las fibras en estos elementos estructurales.

Unreinforced masonry (URM) walls are commonly found in existing and heritage buildings in Canada, either as infill or load-bearing walls. Such walls are vulnerable to sudden and brittle failure under blast loads due to their insufficient out-of-plane strength. The failure of such walls under blast pressures can also result in fragmentation and wall debris which can injure building occupants. Over the years, researchers have conducted experimental tests to evaluate the structural behaviour of unreinforced masonry walls under out-of-plane loading. Various strengthening methods have been proposed, including the use of concrete overlays, polyurea coatings and advanced fiber-reinforced polymer (FRP) composites. Fabric-reinforced cementitious matrix (FRCM) is an emerging material which can also be used to strengthen and remove the deficiencies in unreinforced masonry walls. This composite material consists of a sequence of one or multiple layers of cement-based mortar reinforced with an open mesh of dry fibers (fabric). This thesis presents an experimental and analytical study which investigates the effectiveness of using FRCM composites to improve the out-of-plane resistance of URM walls when subjected to blast loading. As part of the experimental program, two large-scale URM masonry walls were constructed and strengthened with the 3-plies of unidirectional carbon FRCM retrofit. The specimens included one infill concrete masonry (CMU) wall, and one load-bearing stone wall. The University of Ottawa Shock Tube was used to test the walls under gradually increasing blast pressures until failure, and the results were compared to those of control (un-retrofitted) walls tested in previous research. Overall, the FRCM strengthening method was found to be a promising retrofit technique to increase the blast resistance of unreinforced masonry walls. In particular, the retrofit was effective in increasing the out-of-plane strength, stiffness and ultimate blast capacity of the walls, while delaying brittle failure and reducing fragmentation. As part of the analytical research, Single Degree of Freedom (SDOF) analysis was performed to predict the blast behaviour of the stone load-bearing retrofit wall. This was done by computing wall flexural strength using Plane Section Analysis, and developing an idealized resistance curve for use in the SDOF analysis. Overall, the dynamic analysis results were found to be in reasonable agreement with the experimental maximum displacements.

In the last decades the theme of structural rehabilitation has acquired great importance and the adoption of composite materials in civil engineering applications has been a turning point in this field. The cement-based matrix of FRCM composites presents many advantages for their application to historical buildings. This dissertation presents a study of the influence of composite bonded length and width on the load response and failure mode. Two types of mortar matrix and two different steel densities were employed. The classical push pull configuration is adopted where fibers are pulled while the masonry block is restrained. Based on the experimental results and through a fracture mechanics approach, the cohesive material laws for mode II was obtained. For the completeness of the work, the characterization of each material involved in the single-lap shear test has been achieved.

Negli ultimi decenni sono state sviluppati nuovi materiali e tecnologie per il rinforzo e la riabilitazione delle strutture esistenti. I sistemi più recenti per il rinforzo esterno ed il recupero strutturale sono materiali compositi costituiti da fibre raggruppate in forma di tessuto ed impregnate ed immerse in una matrice inorganica. Quando il tessuto è composto da fibre di aramide, vetro, basalto, PBO o carbonio, questi compositi sono comunemente definiti Fabric Reinforced Cementitious Matrix (FRCM), mentre, quando il tessuto è fatto da micro-trefoli di acciaio, sono definiti Steel Reinforced Grout (SRG). In accordo con le rispettive normative, negli Stati Uniti le proprietà meccaniche dei compositi FRCM/SRG si misurano tramite una prova di tensione diretta su provini caricati utilizzando ancoraggi a forcella (clevis grip). In Europa, invece, si ricorre ad una prova di aderenza o single-lap shear su compositi applicati su un substrato cementizio o in muratura. L’obiettivo di questa tesi è confrontare i risultati ottenuti mediante i due metodi di caratterizzazione sviluppando una campagna sperimentale su due diversi tipi di compositi: un FRCM con fibra di carbonio (CFRCM) e un composito SRG. L’effetto di tre diverse lunghezze di ancoraggio è stato studiato per il sistema CFRCM. L’influenza del numero di strati di tessuto è stata analizzata sia per il sistema CFRCM che SRG considerando uno o due strati. I risultati mostrano che le differenti condizioni al contorno influenzano in modo significativo la caratterizzazione dei compositi. Per ottenere una misura rappresentativa delle proprietà meccaniche dei compositi FRCM/SRG, è richiesta una lunghezza di ancoraggio sufficiente. Questo studio contribuisce a sviluppare un database sperimentale che consenta la definizione di affidabili protocolli di caratterizzazione. Inoltre, fornisce informazioni rilevanti ai fini progettuali riguardo la lunghezza di ancoraggio adeguate e all’efficacia di applicazioni multistrato.

In this thesis technical and economic analysis of Fiber Reinforced Composite Polymer (FRPC) bridges was performed. Current condition and main issues of conventional bridges in the world and in Lithuania are assessed, main defects are indicated. In this thesis FRPC is considered as an alternative solution for bridge construction. Application range of FRPC for bridge construction is classified and actual bridge examples are analysed. Further, main properties of FRPC are introduced, taking into account influence of material composition, manufacturing technology, long term effects and advantages over conventional materials. Load-deformation, failure behavior analysis of FRPC bridge decks and bridges revealed advantages over conventional bridge solutions and design issues. In addition, existing codes for FRPC bridge design are analysed, design peculiarities are emphasized and current problems are identified. Performed Life Cycle Cost (LCC) analysis revealed financial viability of FRPC bridges. Finally, main conclusions and problems to be solved are stated and FRPC application potential for bridges construction in Lithuania is suggested. Performed analysis revealed that FRPC application for bridges construction is technically and economically viable solution.
Šiame magistriniame darbe atlikta Pluoštais Armuotų Polimerinių Kompozitinių (PAPK) tiltų techninė ir ekonominė analizė. Nagrinėjama esama pasaulio ir Lietuvos tiltų būklė, nustatytos būdingos problemos bei defektai. Šiame darbe PAPK yra svarstoma kaip alternativi medžiaga tiltų statybai. Atlikta PAPK panaudojimo klasifikacija tiltų statybai, analizuojami esami PAPK tiltų pavyzdžiai bei jų paplitimas. Toliau nustatomos mechaninės bei fizinės PAPK savybės, atsižvelgiant į medžiagos sandarą, gamybos būdą, ilagalaikius veiksnius ir privalumus lyginant su plienu ir gelžbetoniu. Pagal atliktą PAPK tiltų ir perdangų apkrovos-deformacijų, suirimo analizę nustatyta elementų elgsena, pateiktos pagrindinės problemos bei privalumai palyginus su tradiciniais tiltų sprendiniais. Taip pat išnagrinėtos PAPK tiltų projektavimų normos, pateikti skaičiavimų ypatumai bei problemos. Paskutiniame skyriuje atlikta Gyvavimo Ciklo Kainos analizė parodė PAPK tiltų finansinį įgyvendinamumą. Darbo pabaigoje pateikiamos pagrindinės išvados, rezultatai, spręstinos problemos bei PAPK tiltų panaudojimo rekomendacijos Lietuvoje. Atlikta techninė ir ekonominė analizė parodė, jog PAPK panaudojimas tiltų statybai yra techniškai ir ekonomiškai efektyvus sprendimas.

There has been an overwhelming interest in public Wi-Fi due to the increasing number of mobile users and a growing perception that Wi-Fi provides better connection experience at lower costs. Moreover, end users increasingly expect Wi-Fi to be free, thereby motivating a strong transition in leading markets to provide free-to-the-end-user Wi-Fi. Providing free internet to the users is a challenge as potential solutions must be self-sustainable and provide sufficient financial returns. Framework for Advertisement-based Community Wi-Fi access, called FRAC is a self-sustainable advertisement-based community network sharing framework which has the competence to provide significant financial returns. FRAC provides free internet access to its users by motivating Wi-Fi access point (AP) owners to share their internet service for benefits. FRAC builds on privately or commercially-owned, existing Wi-Fi infrastructure. The users accessing the internet using this framework provide a strong customer base for online marketing and advertising which provides the revenue to sustain this framework.

This thesis describes the design and implementation of a prototype of the FRAC system. The design of key features of the framework such as user authentication, advertisement delivery, quality of service, messaging and security, are described, based on which an overall design of the framework is provided. The prototype developed includes a browser extension to support browser-based devices like laptops, netbooks and embeddable software that can be installed on wireless routers with Linux-based dd-wrt firmware.
Master of Science

Il mondo dei materiali compositi è in continua evoluzione ed il loro utilizzo per il rinforzo, l’adeguamento sismico e la messa in sicurezza di strutture civili è diventata una pratica comune tra gli ingegneri ed architetti. Gli FRCM (Fabric Reinforced Cementitious Matrix) rappresentano una nuova metodologia per il rinforzo strutturale e si stanno proponendo come una valida alternativa ai più affermati FRP, ogni volta che le condizioni di progetto non permettano l'uso di compositi a base di polimeri organici. Gli FRCM sono definiti dall’American Concrete Institute (ACI549) come dei sistemi costituiti dall’accoppiamento di uno o più strati di rete di fibra a elevate prestazioni e di una matrice inorganica stabilizzata impiegata con la funzione di adesivo. Gli FRCM sono generalmente costituiti da reti di fibre secche, tuttavia, si è dimostrato che il legame di interfaccia matrice-fibra non è ottimale, in quanto soltanto i filamenti esterni in contatto con la matrice sono in grado di trasferire gli sforzi, mentre i filamenti interni si sfilano a causa al basso attrito tra le fibre. Questo lavoro ha lo scopo di contribuire a migliorare ed approfondire lo stato dell’arte dei sistemi FRCM in diverse direzioni ed è suddiviso in quattro studi. In particolare la ricerca si è dedicata alla caratterizzazione di diversi sistemi FRCM, in modo da chiarire la differenza in termini di comportamento e prestazioni tra reti di fibre secche o apprettate, di analizzare gli effetti delle elevate temperature sulle proprietà meccaniche degli FRCM, di valutare l'efficacia nell’utilizzo di diverse malte (cementizie e geopolimeriche) e la compatibilità di quest’ultime con supporti in muratura. Lo scopo del primo studio è quello di analizzare come l’utilizzo di diversi tipi di coating (pre-impregnazione a base di resine epossidiche) applicati a reti bi-direzionali in fibra di carbonio vada ad influenzare il comportamento di interfaccia fibre-malta e le proprietà meccaniche dei sistemi FRCM. L'efficacia del coating è stato studiato mediante test di trazione diretta, pull-off e di adesione al supporto. La sperimentazione è stata condotta combinando diversi tipi di rete in carbonio e matrici cementizie, variando il livello di pre-impregnazione del tessuto durante la sua fabbricazione (leggera, media e completa impregnazione). Inoltre, è stato sperimentato e studiato l'utilizzo di uno strato di sabbia quarzifera applicato sulle fibre dopo l’impregnazione. Le prove sperimentali hanno dimostrato un notevole miglioramento del legame di interfaccia tra le fibre e la matrice inorganica e, quindi, un generale miglioramento delle prestazioni del sistema FRCM, anche impregnando le fibre parzialmente, a seconda del tipo di malta usata. Lo scopo del secondo studio è quello di valutare il comportamento meccanico dei sistemi FRCM sottoposti ad alte temperature. Diversi sistemi FRCM sono stati valutati, utilizzando reti bidirezionali in fibra di carbonio secche o pre-impregnate. La campagna sperimentale ha riguardato test di trazione monoassiale su provini di FRCM e test di adesione a supporti in muratura con temperature comprese tra 20 °C e 120 °C. Il terzo studio riguarda il possibile utilizzo di malte geopolimeriche come matrici per sistemi FRCM, accoppiate a diverse reti in fibra di carbonio. Lo studio ha incluso la caratterizzazione meccanica della malta, prove di trazione e di adesione a supporti in muratura. Infine il quarto studio analizza il legame di interfaccia FRCM-substrato in muratura, considerando l'utilizzo di diversi primers inorganici per migliorare l’adesione al supporto.
Composites materials are continuously evolving and their use for the repair and retrofit of civil structures has become a common practice among the engineering community. Fabric Reinforced Cementitious Matrix (FRCM) system represents a new repair methodology for structural strengthening and is becoming a viable alternative to FRP, whenever the project conditions do not allow the use of organic polymer based composites. FRCM is described by the American Concrete Institute (ACI) committee 549 like a composite material consisting of a sequence of one or more layers of cement-based matrix reinforced with dry fibers in the form of open single or multiple meshes that, when adhered to concrete or masonry structural members, forms a FRCM system. FRCMs are usually constituted by dry fabrics, however, it is proved that the bond at the matrix-fibers interface is not optimal, since only the external filaments are in contact with the matrix and able to transfer the load, while the inner filaments slip due to the low friction between the fibers. This work aims to advance the FRCM state of the art in several directions and is divided in four studies. In particular, the study is devoted to characterize several FRCM systems, to clarify the differences in performance and behavior of dry and coated fabrics, to analyze the effects of high temperatures on the FRCM mechanical properties, to evaluate the effectiveness and compatibility with masonry substrates of different mortars (cementitious and geopolymeric). The purpose of First Study is to analyze how different types and amounts of organic coatings applied to a carbon bi-directional fabric could affect the bond behavior at the fiber-mortar interface and mechanical properties of the FRCM system. The effectiveness of coating treatments applied on the fabrics surface was studied by means of direct tensile, pull-off and shear-bond double-lap tests. Experimentation was carried out on different combinations of carbon fabrics and mortars, by varying the level of pre-impregnation of the fabric during the manufacturing process. In addition, the use of a quartz sand layer applied to the fabric after impregnation was investigated. Experimental evidence showed a promising enhancement of the bond between fabric and matrix and, therefore, improved performances of the entire FRCM system even with the use of low percentages of resin, depending on the type of mortar used. The purpose of Second Study is to evaluate the FRCM mechanical behavior under high-temperature conditions. Different FRCM systems were evaluated including carbon fabrics with dry or completely impregnated fibers. The experimental campaign comprised of uniaxial tensile and double-shear bond tests performed under temperatures ranging from 20°C to 120°C. Third Study explores the use of a geopolymer mortar coupled with different carbon fabrics for FRCM applications. The study included the mechanical characterization of the mortar, tensile and double-shear bond tests of the FRCM system when applied to masonry substrates. Finally, Fourth Study analyzes the bond at the FRCM to masonry substrate interface, considering the use of different inorganic primers to improve the interface bond.

Questa tesi presenta i risultati di una campagna sperimentale incentrata sulla caratterizzazione della trazione dei basalt e glass FRCM e della caratterizzazione del legame di aderenza composito-Calcarenite. Il lavoro sperimentale è completato dalla proposta di due modelli numerici sia per prove di trazione che per quelle di aderenza. L'indagine sperimentale è stata condotta considerando l'influenza di diversi rinforzi, matrici e metodi di prova. I risultati sperimentali consentono di valutare l'effetto della malta sulle curve sforzo-deformazione, la resistenza, la duttilità e le modalità di crisi. Inoltre, la tesi fornisce un importante contributo per valutare l'influenza di diversi metodi di prova (es. clamping e clevis come riportato da diversi standard e linee guida) sulle prestazioni dei sistemi FRCM testati a trazione. Inoltre, la correlazione dell'immagine digitale è stata utilizzata per misurare le tensioni di trazione e per analizzare le modalità di crisi offrendo una caratterizzazione meccanica accurata. L'elemento di principale novità è l'adozione di un set-up per le prove di aderenza modificato e progettato per analizzare l'influenza della dimensione del composito sulla lunghezza e la resistenza del legame. Un'analisi approfondita dei risultati conferma l'efficacia di questo innovativo set-up. Infine, vengono presentati due modelli numerici che tentano di fornire un semplice strumento numerico per valutare il comportamento costitutivo dei sistemi FRCM. I modelli sono stati calibrati sulla base delle curve sperimentali sforzo-deformazione e carico-slittamento dimostrando di essere uno strumento efficace per prevedere il comportamento meccanico dei materiali compositi FRCM.
This thesis presents the results of an experimental campaign focused on the tensile characterization of basalt and glass FRCM and composite-calcarenite bond characterization. The experimental work is complemented by the proposal of two numerical models both for tensile and bond tests. The experimental investigation was carried out considering the influence of different reinforcements, matrices and testing methods. Experimental results provide for assessing the effect of mortar grade on the stress-strain curves, strength, ductility and failure modes. Moreover, the thesis provides an important contribution to assess the influence of different testing methods (i.e. clamping and clevis as reported by different standard and guidelines) on the performance of the FRCM systems tested in tension. Moreover, the Digital image correlation was used to measure the tensile strains and to analyse the failure modes offering an accurate mechanical characterization. The main element of novelty is the adoption of a modified bond test set-up designed to analyse the influence of the composite size on bond length and strength. A deep analysis of the results confirms the effectiveness of this innovative set-up. Finally, two numerical models are presented attempt at providing a simple numerical tool for capturing the constitutive behaviour of the FRCM systems. The models were calibrated on the basis of the experimental stress-strain and load-slip curves showing to be an effective tool for predicting the mechanical behaviour of the FRCM composites.

Fibre reinforced concrete (FRC) presents objectively proven advantages in terms of post-cracking strength and manufacturing procedures. As a result, FRC with structural responsibility is increasingly being used in the construction industry. However, some concerns still remain regarding design and performance given the uncertainties concerning the effect of the distribution and orientation of the fibres. In this context, further research is required to improve current tools to characterize and design FRC structures. The main topics addressed in this thesis are oriented to analyse the influence of fibres at the design stage, verify whether the constitutive models are representative and suitable to predict the response of real-scale elements and simplify FRC quality control. At the design stage, the influence of size-effect on the bending tests used to determine the constitutive model has been analysed. Additionally, a model to estimate the residual strength of FRC based on the orientation of the fibres is proposed. Flexural tests on real-scale slabs reinforced with rebars and fibres have been analysed and compared to numerical simulations using the constitutive model of the Model Code 2010 (MC2010). Finally, a correlation based on the Barcelona test (BCN) is proposed as an alternative to the three-point bending test in quality control. The first part of the study focuses on the pre-design stage of FRC. Standard and non-standard specimens were tested under a three-point bending test (3PBT) configuration to calculate the parameters defining the MC2010 constitutive model for FRC. The results revealed that the size-effect in small non-standard specimens can be mitigated if, instead of the CMOD, the rotation of the sample is used as the reference parameter to determine the residual strengths associated to the constitutive law. Subsequently, a model to estimate the post-cracking strength of FRC is presented. Given a degree of isotropy and a content of fibres, the model assigns a position and an orientation to each fibre. Assuming that only fibres contribute to the tensile strength after cracking, the pull-out load of all the fibres combined with the sectional equilibrium can be used to determine the post-cracking strength of FRC. The estimations of the post-cracking strength curves are able to reflect the influence of the specimen dimension as well as the content and the orientation of the fibres. After the pre-design stage, real-scale slabs with different combinations of rebars and fibres were tested to analyse the influence of fibres on the flexural behaviour, cracking patterns and ductility. The experimental results were used to verify the predicted flexural response of the slabs simulated by means of sectional analyses and finite element methods based on the constitutive law of the MC2010. The simulations revealed a general overestimation of the flexural performance when compared to the experimental results. The last part of the study aims to present an alternative method to optimize and streamline quality control of FRC based on a correlation between the 3PBT and the BCN. For this purpose, an experimental programme on mixes with different rheologies, compressive strengths and types and contents of fibres was conducted. The procedure to determine such a correlation is described while showing the importance of considering confidence intervals in the presence of results with high variability as in FRC.
El hormigón reforzado con fibras (HRF) presenta ventajas objetivamente probadas en términos de resistencia residual y procesos de producción. En consecuencia, el HRF con responsabilidad estructural ha experimentado una creciente demanda en el sector de la construcción. No obstante, su uso aún suscita ciertas preocupaciones debidas esencialmente a la influencia de la distribución y la orientación de las fibras en la capacidad resistente. En este sentido, se hace necesario continuar investigando con el objeto de mejorar los métodos actuales de caracterización y diseño del HRF. Los principales aspectos que se abordan en esta tesis están orientados a analizar la influencia de las fibras en la etapa de diseño, verificar la capacidad de los modelos constitutivos para predecir la respuesta estructural de elementos a escala real y simplificar el control de calidad del HRF. En la etapa de diseño, se ha estudiado la influencia del efecto escala en los ensayos de flexión destinados a obtener las ecuaciones constitutivas de HRF. Asimismo, se ha propuesto un modelo para estimar la resistencia residual del HRF basado en la orientación de las fibras. Por otro lado, se ha analizado el comportamiento a flexión de losas reforzadas con fibras y barras de acero, tras lo que se ha comparado los resultados experimentales de dichos ensayos con simulaciones numéricas basadas en las ecuaciones constitutivas descritas en el Model Code 2010 (MC2010). Finalmente, se propone una correlación basada en el ensayo Barcelona (BCN) como alternativa al ensayo a flexión a tres puntos (3PBT) en la fase de control de calidad. La primera parte del estudio se enfoca en la etapa de pre-diseño del HRF. Para ello, se han ensayado probetas prismáticas de distintos tamaños bajo una configuración de ensayo 3PBT para calcular los parámetros que definen la ecuación constitutiva del HRF según los criterios del MC2010. Los resultados muestran que el efecto escala puede verse reducido utilizando el giro, en lugar del CMOD, como parámetro de referencia para calcular las resistencias residuales asociadas a la ecuación constitutiva. Posteriormente, se propone un modelo para estimar la resistencia residual del HRF. A partir de la isotropía y el contenido de fibras, se asigna a cada fibra una posición y una orientación determinada. Asimismo, el modelo asume que en estado fisurado únicamente las fibras contribuyen a la resistencia a tracción. De este modo, la contribución al arrancamiento de todas las fibras en combinación con el equilibrio seccional puede utilizarse para calcular la resistencia residual del HRF. De acuerdo con los resultados obtenidos, la resistencia residual calculada mediante el modelo es capaz de reflejar la influencia del tamaño de probeta, el contenido de fibras y su orientación. Tras el estudio de la fase de pre-diseño, se ensayaron losas a escala real con diferentes combinaciones de HA y HRF con el objeto de analizar la influencia de las fibras en la respuesta a flexión, la aparición de fisuras y la ductilidad. Los resultados experimentales se utilizaron para verificar la idoneidad del modelo constitutivo del MC2010 cuando se utiliza para simular el comportamiento a flexión mediante análisis seccional y tridimensional mediante elementos finitos. Este estudio muestra que los resultados de las simulaciones presentan una sobreestimación generalizada de la respuesta a flexión de las losas en comparación con los resultados experimentales.

This work shows that toughness (resistance) to fracture propagation is an inherent characteristic of cohesionless particulate materials, which is significant for understanding hydraulic fracturing in geotechnical, geological, and petroleum applications. We have developed experimental techniques to quantify the initiation and propagation of fluid-driven fractures in saturated particulate materials. The fracturing liquid is injected into particulate materials, where the fluid flow is localized in thin crack-like conduits. By analogy, we call them 'cracks' or 'hydraulic fractures'. Based on the laboratory observations and scale analysis, this work offers physical concepts to explain the observed phenomena. When a fracture propagates in a solid, new surfaces are created by breaking material bonds. Consequently, the material is in tension at the fracture tip. In contrast, all parts of the cohesionless particulate material (including the tip zone of hydraulic fracture) are likely to be in compression. In solid materials, the fluid front lags behind the front of the propagating fracture, while the lag zone is absent for fluid-driven fractures in cohesionless materials. The compressive stress state and the absence of the fluid lag are important characteristics of hydraulic fracturing in particulate materials with low, or no, cohesion. Our experimental results show that the primary factor affecting peak (initiation) pressure is the magnitude of the remote stresses. The morphology of fracture and fluid leak-off zone, however, changes significantly not only with stresses, but also with other parameters such as flow rate, fluid rheology, and permeability. Typical features of the observed fractures are multiple off-shots and the bluntness of the fracture tip. This suggests the importance of inelastic deformation in the process of fracture propagation in cohesionless materials. Similar to solid materials, fractures propagated perpendicular to the least compressive stress. However, peak injection pressures are significantly greater than the maximum principle stresses in the experiments. Further, by incorporating the dominate experimental parameters into dimensionless form; a reasonable power-law fit is achieved between a dimensionless peak injection pressure and dimensionless stress. Scaling indicates that there is a high pressure gradient in the leak-off zone in the direction normal to the fracture. Fluid pressure does not decrease considerably along the fracture, however, due to the relatively wide fracture aperture. This suggests that hydraulic fractures in unconsolidated materials propagate within the toughness-dominated regime. Furthermore, the theoretical model of toughness-dominated hydraulic fracturing can be matched to the experimental pressure-time dependences with only one fitting parameter. Scale analysis shows that large apertures at the fracture tip correspond to relatively large 'effective' fracture (surface) energy, which can be orders of magnitude greater than typical for hard rocks.

The rehabilitation of existing masonry elements through jacketing of columns using composite materials is becoming a remarkable technique in several applications that aim to increase the strength of existing masonry building. An experimental campaign was conducted with Steel- and -Basalt Fiber Reinforced Cementitious Matrix (FRCM) systems, in order to test new products that might increase the advantages in terms of good adhesion to masonry substrate, breathability of the system, efficiency in aggressive environments, ease of installation and reversibility, which are essential for the preservation of historical buildings. The mean objective of this experimental study was to investigate the state of the improvement of square masonry columns, built in alternate stretcher and header bond configuration using as material confinement Steel- and-Basalt FRCM system, subjected to axial compression. Moreover, the effectiveness and influence of the confinement in terms of load-bearing capacity and strain distribution with respect to unconfined prisms was carried out. An optical technique, known as Digital Image Correlation (DIC), was employed to understand the interaction between the unit masonry components.

In the last years, due to many severe seismic events, it becomes more and more important to understand the structural performance of stone masonry structures subjected to seismic actions and structural reinforce became an important task in civil engineering. The developments of innovative techniques for structural retrofitting represent a great change in order to reduce the seismic vulnerability of stone masonry buildings. Beside the traditional reinforce techniques, new reinforce born such as Fiber Reinforced Polymer (FRP) and Fiber Reinforced Cementitious Matrix (FRCM) The aim of this thesis is to study the shear strength of masonry panels, subjected to in-plane actions, reinforced with FRCM

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Os fungicidas agrícolas consistem num componente importante da produção agrícola, exercendo papel primordial principalmente no momento em que os demais métodos de controle mostram-se ineficientes. Sua intensa utilização vem provocando um sério problema, que é a resistência dos fungos a alguns princípios ativos utilizados. Quando se utilizam os fungicidas em um programa de manejo de doenças, é muito importante o conhecimento do mecanismo de ação das moléculas utilizadas, visando evitar erros que podem comprometer sua vida útil e, em alguns casos, gerar situações de difícil resolução como está. Porém, nem sempre as informações necessárias sobre os fungicidas utilizados na agricultura estão disponíveis, necessitando-se recorrer a inúmeras obras e trabalhos científicos para melhor compreender seu funcionamento. Este trabalho teve como objetivo a elaboração de uma revisão que abordasse todos os grupos de fungicidas utilizados no mercado nacional e internacional, disponibilizando informações importantes àqueles que fazem uso desta modalidade de controle, quer para recomendação direta no controle de doenças, quer para pesquisa e desenvolvimento que esclareçam sua performance regional, ou ainda na consulta acadêmica. Utilizou-se como diretriz para formatação deste trabalho as normas estabelecidas pelo FRAC (Fungicide Resitance Action Committee), que são internacionalmente conhecidas e respeitadas pelos usuarios de fungicidas. Juntamente com o mecanismo de ação, procurou-se também esclarecer alguns pontos importantes no metabolismo dos fungos, principalmente aqueles caracterizados como alvo dos fungicidas.
The fungicides are efficient tools for agriculture, exerting primordial role especially when different methods of control are inefficient. However, the intensive use may result in a serious problem, the fungi resistance against the fungicide. When the fungicides are used in a program of disease management, knowing the mechanism of action of the molecules used is of the most importance, in order to prevent errous which can compromises its lifetime and, in some cases, to produce situations of difficult resolution. However, its not always that the information about the fungicides used in agriculture are readily available, and in that case, there's the need to consult several books and scientific pappers. The target of this work is to review and organize the information about all groups of fungicides used in the market, providing important information to those who are going to use this tool, for direct recommendation in the control of diseases, or for research and development which will help its regional performance, or for academic purposes. This work was based on the norms used by FRAC (Fungicide Resistance Action Committee), which are internationally known and respected by the users of fungicides. Additionally to the mechanism of action, it was also presented some important points in the fungi metabolism, mainly related to fungicide targets.

Resumo: Os fungicidas agrícolas consistem num componente importante da produção agrícola, exercendo papel primordial principalmente no momento em que os demais métodos de controle mostram-se ineficientes. Sua intensa utilização vem provocando um sério problema, que é a resistência dos fungos a alguns princípios ativos utilizados. Quando se utilizam os fungicidas em um programa de manejo de doenças, é muito importante o conhecimento do mecanismo de ação das moléculas utilizadas, visando evitar erros que podem comprometer sua vida útil e, em alguns casos, gerar situações de difícil resolução como está. Porém, nem sempre as informações necessárias sobre os fungicidas utilizados na agricultura estão disponíveis, necessitando-se recorrer a inúmeras obras e trabalhos científicos para melhor compreender seu funcionamento. Este trabalho teve como objetivo a elaboração de uma revisão que abordasse todos os grupos de fungicidas utilizados no mercado nacional e internacional, disponibilizando informações importantes àqueles que fazem uso desta modalidade de controle, quer para recomendação direta no controle de doenças, quer para pesquisa e desenvolvimento que esclareçam sua performance regional, ou ainda na consulta acadêmica. Utilizou-se como diretriz para formatação deste trabalho as normas estabelecidas pelo FRAC (Fungicide Resitance Action Committee), que são internacionalmente conhecidas e respeitadas pelos usuarios de fungicidas. Juntamente com o mecanismo de ação, procurou-se também esclarecer alguns pontos importantes no metabolismo dos fungos, principalmente aqueles caracterizados como alvo dos fungicidas.
Abstract: The fungicides are efficient tools for agriculture, exerting primordial role especially when different methods of control are inefficient. However, the intensive use may result in a serious problem, the fungi resistance against the fungicide. When the fungicides are used in a program of disease management, knowing the mechanism of action of the molecules used is of the most importance, in order to prevent errous which can compromises its lifetime and, in some cases, to produce situations of difficult resolution. However, its not always that the information about the fungicides used in agriculture are readily available, and in that case, there's the need to consult several books and scientific pappers. The target of this work is to review and organize the information about all groups of fungicides used in the market, providing important information to those who are going to use this tool, for direct recommendation in the control of diseases, or for research and development which will help its regional performance, or for academic purposes. This work was based on the norms used by FRAC (Fungicide Resistance Action Committee), which are internationally known and respected by the users of fungicides. Additionally to the mechanism of action, it was also presented some important points in the fungi metabolism, mainly related to fungicide targets.
Orientador: Nilton Luiz de Souza
Coorientador: Wilson Story Venâncio
Banca: Edson Luiz Furtado
Banca: Dauri José Tessmann
Mestre

Il presente lavoro è volto allo studio di soluzioni di rinforzo strutturale di edifici storici in muratura mediante materiali compositi innovativi a matrice inorganica FRCM (Fiber Reinforced Cementitious Matrix). E' stato effettuato un confronto tra due sistemi di rinforzo con compositi SRG (Steel Reinforced Grout) in fibre d'acciaio ad altissima resistenza, nell'ottica di un progetto di miglioramento sismico del teatro Pavarotti di Modena, in particolare della parete di fondo retrostante il palcoscenico. Ipotizzati alcuni meccanismi di collaso della parete, la vulnerabilità sismica della stessa, nei confronti di ciascun meccanismo, è stata valutata attraverso l'analisi cinematica lineare. Successivamente per ogni meccanismo è stato studiato un sistema di rinforzo SRG al fine di incrementare la capacità sismica della parete e il moltiplicatore di collasso.

Frc, a major gene on chromosome 8, conditions fructan levels in onions (Allium cepa L). In order to assist genetic dissection of this locus, this study aimed to determine the factors influencing varying fructan levels in high- and low-fructan genotypes. Mapping families were developed and analysed to study the genetic architecture for the fructan trait, and to check the association of the identified variables with the Frc locus. To facilitate reliable and practicable sugar assays in onions, a newly-adapted high-throughput microplate enzymatic assay was validated in this study. The reliability of using leaf sugars as a representative of bulb sugars in a mapping population was studied. Microplate enzymatic sugar assays were carried out on a segregating onion cross to validate the use of maltases in sugar analysis, and the results obtained were validated against HPLC-PAD. Sucrose measured in microplates employing maltases as the hydrolytic enzyme was in agreement with HPLC-PAD results. Maltase enzymes specifically hydrolysed sucrose in onions, providing an alternate tool in place of expensive sugar assay kits. Use of the microplate-enzymatic assay provided a rapid, cheap and practicable method for sugar analysis in onion. Differences in carbohydrate content, sucrose metabolising enzyme activities and their expression levels were monitored in developing leaf blades and leaf bases of four high- and four low-fructan genotypes. The variation in fructan accumulation between high- and low-fructan genotypes was due to the variation in sucrose metabolism. SPS expression and activity did not vary between high- and low-fructan genotypes. Acid invertase and 1-SST showed significant variation in their activities between the two fructan groups. Post-transcriptional and translational regulation of AI and 1-SST respectively, are suggested. Mapping populations analysed for non-structural carbohydrates showed very wide segregation for fructan (80 to 600 g kg⁻¹) and other NSC content, and were well-suited for detailed genetic and physiological analysis. Single marker analysis was carried out to study the association between the combined enzyme activity (CEA; acid invertase + 1-SST) and the Frc markers. Significant association between CEA and Frc markers has suggested genes regulating acid invertases or 1-SST or both underlie Frc. Leaf blade NSC did not correlate with bulb sugars and thus cannot be used as a phenotypic marker for early selection of bulb NSC traits.

Il presente elaborato finale è la proposta di traduzione dall'italiano al francese del IV capitolo de "Il pinguino senza frac" di Silvio D'Arzo. Alla presentazione dell'autore, dell'illustratrice e dell'opera, segue un inquadramento nel panorama della letteratura per l'infanzia e delle problematiche traduttive connesse a questo ramo letterario. La parte più significativa dell'elaborato si concentra nell'analisi e nella traduzione del testo, con successivo commento alla traduzione, dove sono esposte e giustificate le strategie traduttive adottate per la risoluzione di passaggi critici e la scelta di una soluzione finale.

Fiber reinforced cementitious matrix (FRCM) composites represent a newly-developed promising alternative to traditional materials for strengthening and retrofitting reinforced concrete and masonry structures. FRCM composites present several advantages with respect to fiber reinforced polymers (FRP) composites. However, while FRP composites have been extensively studied in the last decades and several design guidelines and analytical formulations are available, FRCM composites are still in their infancy and very few data are present in the literature. Thus, another issue that should be solved regards the stated need for the anchorage systems to improve FRP and FRCM strength in situations where debonding or lack of development length is a problem. In this study, the effectiveness of the anchorage system and the interaction with an externally bonded FRCM were studied on both concrete beams and masonry columns. The columns and beams were tested until failure condition in the Laboratory of Structural and Geotechnical Engineering (DICAM – LISG) of the University of Bologna, via del Lazzaretto 15/5, Bologna. Test parameters considered for this study are: density of steel fibers, type of anchorages and bending inclination of the fiber exerted as anchorage, respectively 45° for concrete beam and 90° for masonry column. Test results demonstrate that the introduction of additional anchorages improves the effectiveness of the FRCM composites in terms of resistance and loading capacity.

This thesis investigates the repair of impact-damaged prestressed concrete bridge girders with strand splices and fabric-reinforced cementitious matrix systems, specifically for repair of structural damage to the underside of an overpass bridge girder due to an overheight vehicle collision. Collision damage to bridges can range from minor to catastrophic, potentially requiring repair or replacement of a bridge girder. This thesis investigates the performance of two different types of repair methods for flexural applications: strand splice repair, which is a traditional repair method that is often utilized, and fabric-reinforced cementitious matrix repair, which is a relatively new repair method. The overarching goal of this project was to provide guidance for assessment and potential repair of impact-damaged girders. Prestressed concrete girders were tested to failure in flexure in this research. After a control test to establish a baseline for comparison, five tests were performed involving damaging a girder, repairing it using one of the repair methods, and testing it to failure. These tests showed that both strand splice repairs and fabric-reinforced cementitious matrix repairs can adequately restore the strength of an impact-damaged girder when up to 10% of the prestressing strands are severed. Combined repairs can also be a viable option if more than 10% of the prestressing strands are severed, though as the damage gets more severe, girder replacement becomes a more attractive option.
Master of Science

Si analizza il comportamento e la risposta di elementi sottoposti a diversi tipi di sollecitazione. Lo scopo ultimo è quello di valutare l’applicabilità di un modello che permetta di ricavare il comportamento di creep a trazione nei calcestruzzi fibrorinforzati, partendo dai risultati delle prove di creep a compressione e creep a flessione.

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MBA Professional Report
In an effort to foster process improvement and ensure cost-wise support of the ongoing military operations throughout the world, Fleet Readiness Center Southwest (FRC SW) created its Continuous Process Improvement (CPI) as a vehicle to establish cost-wise readiness throughout its organization. The goal of this MBA project is to determine a reasonable range of production at Fleet Readiness Center Southwest (FRC SW) while attempting to maximize flexibility to support the fleet. The success of our project depended on to conducting capacity measurement analysis to support our findings and recommendations in assisting FRC SW. We used several modeling tools to assess capacity, which assisted in locating some of the constraints on the C2 production line at FRC SW. We found that the scope of the C2 production line requires further capacity analysis using tools beyond our project. We concluded our project with a recommendation for future research using modeling and simulation.

"Submitted in partial fulfillment of the requirements for the degree of Master of Business Administration from the Naval Postgraduate School, June 2009."
Advisor(s): Heath, Susan ; Euske, Kenneth. "June 2009." "MBA professional report"--Cover. Description based on title screen as viewed on July 14, 2009. DTIC Identifiers: CPI (Continuous Process Improvement), C2 Greyhound, capacity analysis, process flow. Author(s) subject terms: C2 Greyhound; Capacity Analysis; AirSpeed Toolset; Process Flow; Precedence Diagram; Work Breakdown Structure (WBS); PMI3 Includes bibliographical references (p. 43-44). Also available in print.

Unreinforced masonry (URM) walls are often used as load-bearing or infill walls in buildings in many countries. Such walls are also commonly found in existing and heritage buildings in Canada. URM walls are strong structural elements when subjected to axial loading, but are very vulnerable under out-of-plane loads. This type of loading may come from different sources , including seismic or blast events. When subjected to blast, wall elements experience large pressures on one of their faces due to the high pressure produced in the air when an explosion takes place. This wave of compressed air travels in a very short time and hits the wall causing immense stresses, which result in large shear and bending demands that may lead to wall failure, and the projection of debris at high velocities that can injure building occupants. This failure process is highly brittle due to the very low out-of-plane strength that characterize such walls. In the past years, many investigations have been carried out to enhance the structural behaviour of unreinforced masonry walls under out-of-plane loading. Different strengthening methods have been studied, which include the use of polyurea coatings, the application of advanced fiber-reinforced polymer (FRP) composites or the use of concrete overlays in combination with high performance reinforcement. Fabric-reinforced cementitious matrix (FRCM) is a new composite material that overcomes some of the drawbacks of FRP. This composite material consists of applying coatings which consist of one or more layers of cement-based mortar reinforced with a corresponding open mesh of dry fibers (fabric). This material has been studied as a strengthening technique to improve in-plane and out-of-plane capacity of existing URM walls as well as other structural elements, mostly under seismic actions. This thesis presents an experimental and analytical study which investigates the effectiveness of using FRCM composites to improve the out-of-plane resistance of URM walls when subjected to blast loading. As part of the experimental program, three large-scale URM masonry walls were constructed and strengthened with 1,2 and 3 layers of FRCM using unidirectional carbon fabrics. In all cases the specimens were built as load-bearing concrete masonry (CMU) walls. To increase shear resistance, two of the walls were also grouted with a flowable self-compacting concrete (SCC) mortar. Blast tests were conducted using the University of Ottawa Shock Tube and the results are compared with control walls tested in previous research at the University of Ottawa. The experimental results show that the FRCM retrofit significantly improved the blast performance of the URM load-bearing walls, allowing for increased blast capacity and improved control of displacements. The performance of the retrofit was found to be dependent on the number of retrofit layers. As part of the analytical research, Single Degree of Freedom (SDOF) analysis was carried out to predict the blast behaviour of the strengthened walls. This was done by computing wall flexural strength using plane sectional analysis and developing idealized resistance curves for use in the SDOF analysis. In general, the analysis procedure is found to produce reasonably accurate results for both the resistance functions and wall mid-height displacements under blast loading.

L’utilizzo di compositi fibrorinforzati per il rinforzo e l’adeguamento di strutture esistenti in calcestruzzo armato e in muratura ha raggiunto una grande popolarità negli ultimi decenni. Tra i materiali compositi, i fibrorinforzati a matrice cementizia (fiber reinforced cementitious matrix, FRCM) rappresentano una novità nel mondo del rinforzo e la letteratura disponibile a riguardo è ancora molto limitata. Il presente lavoro si inserisce all’interno di un contesto di campagne sperimentali volte ad approfondire la conoscenza su questi materiali. Uno dei problemi di maggiore importanza nell’utilizzo dei compositi FRCM è costituito dalla valutazione della resistenza al distacco (debonding) del composito dal supporto su cui è applicato. Nel caso di strutture in muratura, i cicli di cristallizzazione salina sono una della cause principali di degrado della murature. In questa tesi vengono analizzati gli effetti della cristallizzazione salina sul debonding di compositi FRCM, con fibre di acciaio galvanizzato a matrice a base di calce idraulica, applicati alla muratura.

Highway bridges in the United States are frequently damaged by overheight vehicle collisions. The increasing number of prestressed concrete bridges indicates that the probability of such bridges being impacted by overheight vehicles has increased. This thesis, sponsored by the Virginia Center for Transportation Innovation and Research (VCTIR), investigated three repair techniques for impact damaged prestressed bridge girders: strand splices, fiber reinforced polymer (FRP) overlays, and fabric reinforced cementitious matrix (FRCM) overlays. The flexural strength of four AASHTO Type III girders, three of which were intentionally damaged and repaired, was evaluated. Six experimental tests were performed on these girders: one undamaged girder test and five repair method tests. Nonlinear beam models and three-dimensional finite element (FE) models were created to predict the behavior of the beams under flexural testing, and subsequently validated and calibrated to experimental test data. The very good accuracy of the beam models indicated that they can be used alone for the performance assessment of damaged and repaired girders. Of course, the analyst must always be aware of the fact that a beam model cannot explicitly account for potentially crucial effects such as diagonal cracking. A direct comparison between repair methods was made by creating analytical models of a prototype girder setup. FRP overlays were seen to restore the most strength, while strand splices were seen to restore the most ductility. From observation, combining repair methods resulted in an additive effect on strength, but the deformation at onset of failure will be governed by the less ductile method.
Master of Science

La tesi studia un tema ancora poco studiato, cioè la durabilità dei materiali fibrorinforzati a matrice inorganica (FRCM) per gli edifici in muratura, concentrando l’attenzione sulla resistenza al degrado causato dalla presenza di sali e di come questi ultimi ne modifichino le prestazioni, soprattutto in termini di efficacia dell’adesione tra rinforzo e substrato in muratura. L'elaborato è organizzato in due sezioni: - una parte di analisi della letteratura tecnico-scientifica disponibile, in cui si definiscono i materiali compositi e si affronta il tema della durabilità in relazione a vari fattori di degrado; - una parte sperimentale in cui invece si illustra tutta l’attività sperimentale svolta, dalla descrizione dei materiali e dei metodi impiegati al commento dei risultati ottenuti. Nello specifico, sono stati studiati dei provini di muratura rinforzati con compositi a matrice di calce idraulica, rete in fibra di vetro e trefoli d’acciaio. I provini sono stati sottoposti a cicli di degrado accelerato allo scopo di indagare gli effetti della cristallizzazione salina sulle prestazioni meccaniche. Terminati i cicli, sono state eseguite le prove di taglio diretto per poter valutare l’aderenza del rinforzo al substrato. Successivamente, sono state effettuate le prove sui materiali: la cromatografia ionica per determinare la concentrazione di sali e la porosimetria ad intrusione di mercurio per valutare la distribuzione dei pori e le loro dimensioni. Infine vengono raccolti e illustrati tutti i risultati ottenuti, dall’analisi visiva della documentazione fotografica relativa ai cicli di degrado all’elaborazione dei dati ricavati dai test meccanici e dalle prove in laboratorio.