Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A evolução dos concretos utilizados nas últimas décadas deu origem ao Concreto de Alto Desempenho (CAD), que tem, entre suas características, alta resistência à compressão e baixa permeabilidade. Com o desenvolvimento dos produtos químicos utilizados na construção civil, em especial os superplastificantes e superfluidificantes, a utilização desse tipo de concreto tornou-se cada vez mais freqüente pela possibilidade de se obter uma mistura suficientemente trabalhável utilizando-se fatores água/cimento menores do que 0,35. Devido à sua microestrutura mais homogênea, esse tipo de concreto apresenta um comportamento mais frágil do que os concretos convencionais, exigindo uma melhor caracterização do material. A partir do final da década de 70 começou-se a aplicar os conceitos da Mecânica da Fratura para análise do comportamento de estruturas construídas com esse tipo de concreto. Como em algumas situações a resistência nominal de peças de concreto diminui com o aumento de suas dimensões, houve a necessidade de se considerar o efeito de escala das estruturas a fim de se obter níveis de segurança mais adequados no seu dimensionamento, o que justificou a utilização da Mecânica da Fratura. Neste trabalho a energia de fraturamento foi obtida experimentalmente pelo método do trabalho de fraturamento e pelo método do efeito de escala, por meio de ensaios estáveis de flexão de três pontos em amostras de concreto de alto desempenho com entalhe. Foi também desenvolvida a simulação numérica de uma viga com entalhe, analisada pelo método dos elementos finitos e empregando-se na modelagem constitutiva os conceitos da Mecânica da Fratura aplicada ao concreto. As vigas foram moldadas e ensaiadas no Instituto Politécnico do Rio de Janeiro (IPRJ) da Universidade do Estado do Rio de Janeiro (UERJ) na cidade de Nova Friburgo. Os ensaios foram realizados com controle de deslocamento da célula de carga. Foram ensaiadas três séries de 12 vigas, com quatro dimensões diferentes, geometricamente proporcionais, e três amostras para cada dimensão, totalizando 36 vigas. As alturas utilizadas para as vigas foram 38, 76, 152 e 304 mm, e sua espessura foi mantida constante igual a 38 mm. Os corpos de prova cilíndricos, para caracterização da resistência à compressão do concreto, foram moldados no IPRJ e rompidos no laboratório de engenharia civil da UERJ, na cidade do Rio de Janeiro. Os concretos utilizados apresentaram resistência à compressão média de 70 MPa. / The evolution of the concrete mixes used during the last decades gave birth to the High Performance Concrete (HPC), which, among its main characteristics, presents high strength and low permeability. With the development of chemical products used in civil engineering constructions, mainly the superplasticizers, the use of this kind of concrete has become more and more frequent due to the possibility of obtaining a workable mixture with a water/cement ratio lower than 0.35. Due to its more homogeneous microstructure, the HPC presents a more fragile behavior than the conventional concrete, demanding a better characterization of the material. At the end of the 1970s, concepts of the Fracture Mechanics started to be used for the analysis of the structural behavior of concrete structures. As the nominal stress of the material decreases as the size of the structure increases, it became necessary to consider this size effect in the analysis in order to obtain more suitable levels of security. This fact justifies the use of the Fracture Mechanics in the structural analysis of concrete structures. In this work, the fracture energy was experimentally obtained using the work-offracture method and the size effect method by performing three-point bend tests in HPC notched beams. It was also developed a numerical simulation of the tests, performing the analysis through the Finite Element Method and applying the concepts of the Fracture Mechanics of Concrete into the constitutive model. The notched beams were molded and tested at the Polytechnic Institute of the State University of Rio de Janeiro (IPRJ/UERJ), located in the city of Nova Friburgo. The tests were controlled by the vertical displacement of the load cell. Three series of twelve beams with four geometrically similar sizes were tested. Three samples for each size were cast, making an amount of 36 beams. The beams were 38, 76, 152 and 304 millimeters high and the width was kept constant equal to 38 millimeters. To characterize the concrete compression strength, 100x200 millimeters cylinders were molded at the IPRJ and tested at the UERJ civil engineering laboratory in the city of Rio de Janeiro. The tested concretes presented a medium compressive strength of 70 MPa.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A evolução dos concretos utilizados nas últimas décadas deu origem ao Concreto de Alto Desempenho (CAD), que tem, entre suas características, alta resistência à compressão e baixa permeabilidade. Com o desenvolvimento dos produtos químicos utilizados na construção civil, em especial os superplastificantes e superfluidificantes, a utilização desse tipo de concreto tornou-se cada vez mais freqüente pela possibilidade de se obter uma mistura suficientemente trabalhável utilizando-se fatores água/cimento menores do que 0,35. Devido à sua microestrutura mais homogênea, esse tipo de concreto apresenta um comportamento mais frágil do que os concretos convencionais, exigindo uma melhor caracterização do material. A partir do final da década de 70 começou-se a aplicar os conceitos da Mecânica da Fratura para análise do comportamento de estruturas construídas com esse tipo de concreto. Como em algumas situações a resistência nominal de peças de concreto diminui com o aumento de suas dimensões, houve a necessidade de se considerar o efeito de escala das estruturas a fim de se obter níveis de segurança mais adequados no seu dimensionamento, o que justificou a utilização da Mecânica da Fratura. Neste trabalho a energia de fraturamento foi obtida experimentalmente pelo método do trabalho de fraturamento e pelo método do efeito de escala, por meio de ensaios estáveis de flexão de três pontos em amostras de concreto de alto desempenho com entalhe. Foi também desenvolvida a simulação numérica de uma viga com entalhe, analisada pelo método dos elementos finitos e empregando-se na modelagem constitutiva os conceitos da Mecânica da Fratura aplicada ao concreto. As vigas foram moldadas e ensaiadas no Instituto Politécnico do Rio de Janeiro (IPRJ) da Universidade do Estado do Rio de Janeiro (UERJ) na cidade de Nova Friburgo. Os ensaios foram realizados com controle de deslocamento da célula de carga. Foram ensaiadas três séries de 12 vigas, com quatro dimensões diferentes, geometricamente proporcionais, e três amostras para cada dimensão, totalizando 36 vigas. As alturas utilizadas para as vigas foram 38, 76, 152 e 304 mm, e sua espessura foi mantida constante igual a 38 mm. Os corpos de prova cilíndricos, para caracterização da resistência à compressão do concreto, foram moldados no IPRJ e rompidos no laboratório de engenharia civil da UERJ, na cidade do Rio de Janeiro. Os concretos utilizados apresentaram resistência à compressão média de 70 MPa. / The evolution of the concrete mixes used during the last decades gave birth to the High Performance Concrete (HPC), which, among its main characteristics, presents high strength and low permeability. With the development of chemical products used in civil engineering constructions, mainly the superplasticizers, the use of this kind of concrete has become more and more frequent due to the possibility of obtaining a workable mixture with a water/cement ratio lower than 0.35. Due to its more homogeneous microstructure, the HPC presents a more fragile behavior than the conventional concrete, demanding a better characterization of the material. At the end of the 1970s, concepts of the Fracture Mechanics started to be used for the analysis of the structural behavior of concrete structures. As the nominal stress of the material decreases as the size of the structure increases, it became necessary to consider this size effect in the analysis in order to obtain more suitable levels of security. This fact justifies the use of the Fracture Mechanics in the structural analysis of concrete structures. In this work, the fracture energy was experimentally obtained using the work-offracture method and the size effect method by performing three-point bend tests in HPC notched beams. It was also developed a numerical simulation of the tests, performing the analysis through the Finite Element Method and applying the concepts of the Fracture Mechanics of Concrete into the constitutive model. The notched beams were molded and tested at the Polytechnic Institute of the State University of Rio de Janeiro (IPRJ/UERJ), located in the city of Nova Friburgo. The tests were controlled by the vertical displacement of the load cell. Three series of twelve beams with four geometrically similar sizes were tested. Three samples for each size were cast, making an amount of 36 beams. The beams were 38, 76, 152 and 304 millimeters high and the width was kept constant equal to 38 millimeters. To characterize the concrete compression strength, 100x200 millimeters cylinders were molded at the IPRJ and tested at the UERJ civil engineering laboratory in the city of Rio de Janeiro. The tested concretes presented a medium compressive strength of 70 MPa.

Entre 1880 et 1920, l’institution scolaire en France, les pédagogues et les professeurs de pédagogie, les enseignants dans leurs commentaires, les parents souvent inquiets en appellent à la volonté qui explique l’échec lorsqu’elle manque, qui galvanise les énergies si elle s’exerce et qui élève l’esprit quand elle est une ascèse. Au même moment, silencieusement parce que dans les marges de la communauté éducative, se forment les conditions même de la disparition de la volonté. L’Education nouvelle de congrès en congrès desserrera l’étau de cette volonté anémiante. Edouard Claparède invitera à dévolontariser la volonté. L’écho de Jean-Jacques Rousseau prônant l’épanouissement de l’enfance retrouvée légitimera cet effacement de la volonté. Et très vite de volonté il ne sera plus question. Comment expliquer cette contradiction entre cette omniprésence de la volonté et sa disparition ? Deux voies : l’une qui analysera la volonté même, l’autre qui décrira des pratiques éducatives où la volonté a joué un rôle ou celles d’où elle s’est retirée. L’enquête s’en tiendra au mot même de volonté dans ses composants sémantiques et dans l’histoire de sa traduction du grec ou du latin au français, puis au concept qui lui correspond : décomposition en traits, description de ses modalités et évaluation de sa teneur ontologique en dessinant la scène de toute action. Apparaîtront quatre dimensions de la volonté : effort, intention, décision et force, dimensions qui renverront aux vertus épistémiques, à la logique de l’action et à une conception de l’homme. Autrement dit, à quelle anthropologie la volonté comme force correspond-elle ? Et son éviction, quel sujet implique-t-elle ? D’autre part, si la volonté est intention et décision, ne relève-t-elle pas de la logique de l’action, comme son contraire l’acrasie ? Enfin, identifier volonté et effort, c’est redécouvrir les vertus épistémiques de la studiosité, de la curiosité, de l’attention, c’est dire ce qu’elles sont et comment les développer. Il est un dernier point qu’on ne saurait négliger : la volonté, ou du moins son contraire qu’est la paresse, met en jeu l’assise métaphysique de tout homme.Cette analyse sera corrélée, sinon à des pratiques éducatives puisque l’archive en est souvent absente, du moins à des théories ou à des comptes rendus de pratiques dans des genres littéraires le plus divers. D’abord, Célestin Freinet parce qu’il a critiqué la volonté comme instance morale, mais a gardé la notion d’effort s’appuyant peut-être sur le travail comme force d’émancipation, en tout cas comme émanation de la vie. Ensuite Piaget qui transforme la volonté en un contraire de la ligne de moindre résistance dans une conception évolutionniste, la naturalisant ainsi. Puis, Maine de Biran et Pestalozzi qui fondèrent une école presque ensemble, l’un faisant de l’effort le constituant premier de l’homme, l’autre hésitant entre l’épanouissement dévolontarisé et les nécessaires contraintes de toute action. Descartes aussi parce qu’il éduque la volonté conçue comme décision et qu’il la place au cœur de sa logique de sorte que l’homme se caractérise par la générosité qui est l’aptitude à poser des actes judicieux. Enfin, Dewey et Kilpatrick qui substitueront à la volonté l’intérêt s’opposant à l’éducation comme jeu et aux conceptions d’Herbart pour qui rien ne venait de l’élève et pour qui tout s’imposait de l’extérieur. Ce parcours s’achève par une mise en rapport de ces conceptions de la volonté et de certains traits d’anthropologie dans le but de dessiner une logique où le recours à la volonté correspond à un sujet vide et où l’effacement de la volonté suppose un sujet doté d’une intériorité qui ne demande qu’à s’exprimer. Puis, la fiction d’un compte rendu d’un congrès de philosophie de l’éducation permettra de reprendre les perspectives des uns et des autres et d’exprimer leur style de pensée. S'ouvrent alors les perspectives, dans une vision naturaliste, d'un sujet se constituant .... / Between 1880 and 1920 the academic institution of France, pedagogues and professors of pedagogy, teachers writing school reports and worried parents, have called upon the concept of will to explain failure where there is a lack of it, to galvanise energy where it is present and to raise the spirit in the field of asceticism. At the same time, the very conditions for the extinction of the concept of will have been growing quietly, at the margins of the education community. The Modern School Movement, from conference to conference, have been loosening the grip on this debilitating concept. Edouard Claparède suggests the ‘dewilling’ of will. The echo of Jean-Jacques Rousseau defending the blossoming of a rediscovered childhood, adds further weight to the idea of the fading out of the notion of will. How long before the question of will becomes no longer relevant? How can this contradiction between the omnipresent subject of will and its disappearance be explained? There are two approaches: the first analyses will itself, the second describes the educative practices where will plays a role or those where it is absent. The inquiry analyses the semantic components of the word, from its translation in Greek or Latin to French. Alongside this, it investigates the concept behind the word: its distinguishing features, the description of its modalities and its ontological constitution, describing the nature and the elements that make up an action. Four dimensions of will are identified: effort, intention, decision and strength. These dimensions clearly refer to epistemic virtues, the logic of action and the concept of what it is to be human. Put another way, to which anthropological system does will, as a strength, correspond? And in its absence, what idea of human behaviour do we conceive? On the other hand, if will is intention and decision, can it not be assumed that it comes from the logic of action, along with its opposite, akrasia. Finally, to identify will in terms of effort, is to revisit the epistemic virtues of studiousness, curiosity and attention, stating what they are and how to develop them. Another aspect that deserves consideration: will, or at least its opposite, laziness, calls into play the metaphysical bases underpinning human existence. This analysis correlates if not to the educative practices, archival material not often existing, at least to the theories or accounts of practices to be found in the myriad literary genres. Firstly, Célestin Freinet who criticised the idea of will as a moral value, but maintained the idea of effort, emphasing perhaps the notion of work as a liberating force, as an expression of life. Then Piaget, working within the school of evolutionary theory, who transforms will into an opposite of the path of least resistance. This is followed by Maine de Biran and Pestalozzi who almost founded a school together, the former identifying effort as the principal characteristic of man, the later hesitating between the blossoming of the individual that happens outside of will and the essential limits of any given action. Decartes conceives will as a decision which he places at the centre of his theory that man is characterised by generosity, which he defines as the ability to be reasonable. Lastly Dewey and Kilpatrick who substitute will for interest, opposing the idea of education as a game and Herbart’s idea that nothing comes from the student, everything is imposed from external sources. The journey finishes with a bringing together of the concepts of will and certain anthropological features, the aim of which is to draw upon logic where will is called upon in a situation of personal need or is eliminated, presuming that the individual’s inner life is left unexpressed. The imaginary reporting to a fictitious conference between the various educational philosophers would allow the sharing and reformulating of each other’s perspectives along with the investigation of their various styles of thought...

The aim of this thesis is to evaluate the real condition of reinforced concrete beam bridge located in Brno Jundrov. In order to evaluate this condition, there was made the main bridge inspection. Subsequently, a number of diagnostic methods were used, such as hardness tests, concrete stress strenght, ultrasonic pulse method, including their evaluation. In terms of the main inspection, the condition of construction of the bridge was evaluated as V - bad. We found out that the concrete from which the bridge is built of is in very good condition. The problem, however, is the condition of the reinforcement located on the bridge. Based on its condition there must be expected lifespan within the next 5-10 years.

This presented phd thesis focuses on the problems of instability in the rock walls and slopes, whose manifestation is among othersv rockfall and associated risks. It describes the theoretical aspects of the description of instability and summarizes the construction methods and technologies to eliminate them. On the basis of knowledge gained from specific buildings in the Czech Republic and based on the research project solved by author, submits suggestion to optimimalization of the anchoring elements as a basic part of most remediation methods.

The master´s thesis focuses on high-alumina refractory materials used mainly in aluminia metallurgy. Teoretical part of this thesis is aimed at distribution of refractory materials, possibilities of its production and raw material basis. Characteristic properties are described as well as application possibilities in aluminium technology. In final part of this thesis experimental data are evaluated to obtain physical, mechanical, chemical properties of high-alumina refractory materials. Those are used for economical optimalization of raw materials.

The thesis deal with design of coaxial high-speed gear box for small-scale turboshaft engines. At the beginning a study of problems was performed and for design concept was elected version of single-shaft turbo-engine with electric generator. Kinematic diagram, type of gear design, material and lubrication method was designed. Further was solved proposal of basic gearing parameters, choice of the number of tooth and basic proposal calculations were performed. Was performed check calculation of gearing, calculation of bearings durability and was processed design documentation in required range. Designed gear reducer has two stage with three coutershafts, that are deployed evenly about main axis of reducer. First stage is gear with external gearing, second stage with internal gearing. The thesis may be used as a template for next similar gear reducers design.

High-strength concrete (HSC) belongs in the recent years to frequently used types of concrete. It allows realization of static challenging structures and also shows due to its dense structure greater durability especially against aggressive media. Currently HSC construction realization abroad is not exceptional. It’s using in the Czech Republic is still limited. When realized, then in a small scale in civil engineering works. The realization of high-strength concrete structures is closely related with the concrete construction quality verification. Good efficiency of the quality control methods can provide non-destructive testing methods (NDT), especially when investigating strength of concrete built in structure. A lack on relevant data for non-destructive testing of HSC in technical and normative rules is to be considered as a significant deficiency. Evident for HSC generally is the lack in literature on deeper analysis of the factors affecting their non-destructive testing, as well a meaningful methodology or practically usable calibration relationships. HSC differs from ordinary concrete not only by used components, but also by more compact structure with different strength – elastic characteristics. Considering these differences, HSC strength prediction can not be performed by using calibration relationships developed for ordinary concrete. Moreover, the question is to what extent the current knowledge of the NDT results influencing factors can be considered as valid. The paper presents findings on the effects of the key factors affecting the measurement results of Schmidt hardness method and ultrasonic pulse method, including recommendations for the practical application of these methods. The problematic of static vs. dynamic modulus of elasticity was also solved. Calibration equations for predicting the compressive strength of HSC from the non-destructive testing parameter were elaborated, showing high cohesion among variables and practically usability.

The thesis is focused on experimental testing of resilient modulus Mr with triaxial test of chosen unbounded and bounded mixtures used in the sub-base layer of pavement. The reason of testing is to compare results with TP 170 – pavement construction guide containing commonly used values of resilient modulus Mr. Thesis should check if those values are correct and real. For classification of chosen materials there are used another tests like grain size distribution, compaction, California bearing ratio CBR for unbounded mixtures and compressive strength for cement-bounded mixtures.

Detta examensarbete syftar till att utveckla ett nytt sätt att använda betong för inredningsändamål. Betong har alltid använts i större byggnader, infrastruktur och andra kategorier. Nyligen började den moderna inredningen använda betong inomhus, till exempel som bänkskiva eller som en hylla. Arbetet fokuserar på en huvudfråga: Är betong ett bra materialval för inredning? För att besvara denna fråga bestämdes några punkter för att komma till huvudfrågan. Följande punkter behövde testat och analyserad för att komma till svaren:    - Beräkna och testa betongens hållfasthet    - Testa slagtålighet    - Analysera hur betong reagerar med kemikalier med olika pH-värde    - Förhållandet mellan miljö och betong    - Studera produktionen av betong Laborationstest, litteraturskällor och fältstudier användes som metoder för att få ett resultat av ovan nämnda punkter. Resultaten visar att betong kan användas som inredningsändamål och kan användas i större utsträckning än vad som är fallet idag. Sammanfattningsvis är betong ett bra material som används för inredningsändamål och den framtida tekniken kommer att minska koldioxidutsläppen som följer med produktionen av betongen. Det kommer att göra betong ännu bättre som material att använda i framtiden. / The following thesis aims to develop a new way to use concrete as interior material. Concrete has always been used in larger scale buildings, infrastructure and in other categories. Recently the modern interior design started to use concrete indoors for example as countertop or as a shelf. This thesis focuses on one main question: is concrete a good material choice for interior use. To answer that question, we decided to have sub questions to help to get to the main question. The following questions needed test and analysis methods to get to the answers:    - Calculate and test the strength of concrete    - Test impact resistance    - Analyze how concrete reacts with chemicals with different PH-values    - Study the production of concrete    - Relation between environment and concrete Lab tests, literature sources, and field studies was used as methods to answer those questions. The results shows that concrete can be utilized as interior material and can be used to a greater extent than is the case today. In conclusion concrete is a good material as used for interior purposes and the future technology will decrease carbon dioxide emissions that comes with production of the concrete. That will make concrete even better as material to use in the future.