O uso de fibra de aço como reforço no concreto tem sido objeto de várias pesquisas recentes. Com o surgimento do concreto autoadensável reforçado com fibras, a fluidez do concreto aumenta a possibilidade de orientação das fibras na etapa de concretagem, o que pode trazer alterações significativas no comportamento mecânico do concreto endurecido. O objetivo deste trabalho foi verificar a influência das condições de moldagem sobre a resistência residual pós-fissuração de elementos planos moldados com concreto autoadensável reforçados com fibra de aço. Também foi objetivo deste trabalho verificar previamente a combinação de ensaios reológicos com métodos convencionais para controle e caracterização do concreto autoadensável no estado fresco. A caracterização do concreto foi feita com reometria rotacional, caixa-L e espalhamento. Os resultados apontam que o estudo da reologia do concreto é desejável e a combinação dos ensaios de reologia com ensaios convencionais pode trazer mais informações sobre o efeito da adição de fibras. Foram realizados ensaios de punção de placas para avaliar o comportamento mecânico de elementos planos produzidos com concreto lançado em posições distintas. A confirmação da orientação preferencial das fibras como causa da diferença de comportamento foi realizada através de informações obtidas com os ensaios indutivo e Double Edge Wedge Splitting (DEWS) realizados em testemunhos extraídos de placas moldadas sob as mesmas condições. Além disso, comprovou-se que a orientação preferencial gerada pelas condições de lançamento do concreto pode influenciar significativamente na resistência pós-fissuração de elementos estruturais planos. / The use of steel fiber as reinforcement in concrete has been the subject of several recent studies. With the development of self-compacting fiber reinforced concrete, the fluidity of the material could increase the possibility of orientation of fibers during the casting process. That condition could bring significant changes in the mechanical behavior of hardened fiber reinforced concrete. The aim of this study was to investigate the influence of the conditions of casting on the post-cracking residual strength of flat elements molded with self-compacting concrete reinforced with steel fibers. It was also an objective of this work verify previously the combination of rheological tests with conventional methods in order to control and characterize the self-compacting concrete in the fresh state. The characterization of the concrete in fresh state was made with rotational rheometer, L-box and spreading tests. The results showed that the study of the concrete rheology is desirable and combination of rheological tests with conventional testing can provide more information about the effect of fiber addition. The evaluation of the mechanical behavior of flat elements produced under different positions of casting was conducted through test panels submitted to punching loading. The confirmation of the orientation of the fibers as a cause of the difference in the behavior was accomplished through information obtained from the inductive and DEWS tests performed on extracted cores of panels molded under the same conditions. Furthermore, the preferred orientation caused by the concrete flow significant influence on the post-cracking strength of the structural flat elements was shown. The tests carried out with extracted cores endorsed the conclusion that the cause of performance variation is fundamentally linked to the preferred orientation, which is a result of the casting procedure.

Το θέμα της παρούσης Διδακτορικής Διατριβής είναι η συστηματική μελέτη του Αυτοσυμπυκνούμενου Κισσηροδέματος (ΑΣΚ). Ο βασικός σκοπός της υπήρξε η παραγωγή μειγμάτων δομικού ΑΣΚ, προτείνοντας παράλληλα μία μεθοδολογία σύνθεσης, εφαρμόσιμη για κάθε είδος Αυτοσυμπυκνούμενου Σκυροδέματος (ΑΣΣ). Ακόμη, έγινε προσπάθεια να διερευνηθούν τομείς στους οποίους η γνώση για το Αυτοσυμπυκνούμενο Ελαφροσκυρόδεμα (ΑΣΕΣ) είναι ακόμη ελλιπής, όπως η συνάφεια χάλυβα-ΑΣΕΣ, η συμπεριφορά γραμμικών στοιχείων οπλισμένου ΑΣΕΣ έναντι κάμψης και διάτμησης, η κατανομή και οι μέγιστες τιμές των πιέσεων που ασκεί το νωπό ΑΣΕΣ σε ξυλοτύπους και τα χαρακτηριστικά ανθεκτικότητάς του. / In this study an extended investigation of PASCC properties is conducted. The main scope was to produce structural PASCC mixtures, by proposing a mix design methodology applicable for every type of Lightweight Aggregate Self-Compacting Concrete (SCC). Moreover, there has been an attempt to investigate fields where the available knowledge for LWASCC is limited, such as the steel-PASCC bond characteristics, the response of reinforced PASCC elements under reversed bending and shear actions, the formwork pressure development during and after PASCC casting and selected PASCC durability characteristics.

In the face of technological advances in concrete science emerged so-called special concretes and, among these, the self-compacting concrete (SCC), developed in Japan in the 1980s. This concrete is currently considered one of the greatest advances in concrete technology in view of its numerous advantages (decrease of construction duration, decrease of concreting labor, improvement of the working environment, improvement of the quality and durability of structures etc.). The production of SCC requires different mix design methods related to those applied for conventional concrete. Among these differences are highlighted the determination of the aggregate compositions and the addition of fine materials and chemical admixtures. In the case of determining the aggregate composition, the method of unit mass has been applied in SCC. However, it is common the use of this method in binary combinations, but for ternary and quaternary combinations it is quite limited. Thus, this work aimed to analyze the influence of different combinations and compositions of aggregates, determined by the method of unit mass and void ratio, to obtaining and characterization of SCC. For this, initially the procedures of the method was standardized. It was used two types of natural fine and coarse aggregates with different physical characteristics. It was produced 9 different aggregate compositions, four binary, ternary and quaternary four. For each composition, one SCC was formulated, based on previous dosage studies. The selfcompactability properties of the concrete were analyzed by spreading, V funnel test and L box test. In case hardened state the compressive strength was determined. The results showed that different methods of execution procedures showed no differences. The method of unit mass proved to be efficient in determining aggregate compositions to supply the SCC. For the same volume and paste composition (cement, water, chemical and mineral admixtures) the quaternary composition was the most efficient in meeting the properties of selfcompactability and compressive strength. / Diante dos avanços tecnológicos na ciência do concreto surgiram os chamados concretos especiais e, dentre estes, pode-se citar o concreto autoadensável (CAA), desenvolvido no Japão, na década de 1980. Este concreto é atualmente considerado um dos maiores avanços na tecnologia do concreto tendo em vista as suas inúmeras vantagens (diminuição do tempo da obra, diminuição da mão de obra de concretagem, melhora o ambiente de trabalho, melhora a qualidade e durabilidade da estrutura e etc.). A obtenção do CAA requer métodos de dosagens diferentes dos aplicados em concretos convencionais. Dentre essas diferenças se destacam a determinação das composições de agregados e a adição de materiais finos e aditivos químicos. Em se tratando da determinação da composição de agregados o método da massa unitária vem sendo aplicado em CAA. Entretanto é comum sua utilização em combinações binárias, já para combinações ternárias e quaternárias é bastante limitado. Neste sentido, foram analisadas diferentes combinações e composições de agregados, determinadas pelo método da massa unitária e do índice de vazios, na obtenção e caracterização de CAA. Para isso, inicialmente procurou-se padronizar os procedimentos de execução do método. Utilizou-se dois tipos de agregados miúdos e graúdos naturais com diferentes características físicas, sendo produzidas 9 composições distintas, sendo quatro binárias, quatro ternárias e uma quaternária. Para cada composição foi formulado um CAA, tomando como base a dosagem em estudos prévios. As propriedades de autoadensabilidade do concreto foram analisadas através dos ensaios de espalhamento, funil V e caixa L. No estado endurecido a resistência à compressão foi determinada. Os resultados mostraram que os diferentes procedimentos de execução do método não apresentaram divergências. O método da massa unitária mostrou-se eficiente na determinação de composições de agregado para atendimento ao CAA. Para um mesmo volume e composição de pasta (cimento, água, aditivos e adições) a composição quaternária foi a mais eficiente no atendimento às propriedades de autoadensabilidade e resistência à compressão.

Made available in DSpace on 2014-12-17T14:57:49Z (GMT). No. of bitstreams: 1 EdilbertoVB_TESE.pdf: 8017732 bytes, checksum: 5be77df6bb358232ee29ccf11e397f58 (MD5) Previous issue date: 2011-02-10 / The search for alternative materials with lower density, reduction in heat transfer and propagation of noise associated with the ease of handling and application in concrete structures, represents an enormous challenge in the formulation and knowledge of the performance of self-compacting lightweight concrete, which has technology little known nationally, and appears on the international scene as an innovative material and alternative to conventional concrete. Based on these, this study set out to study self-compacting lightweight concrete made with two distinct grades of expanded clay associated with the addition of plasticizing/superplasticizers additives and mineral additions of metakaolin and bagasse ash of sugar cane. There is also an object of study, evaluation of pozzolanic activity of mineral admixtures and their influence on the durability characteristics of concrete. The rheological, physical, mechanical and microstructural analysis in this study served as basis in the classification of concretes autoadens?veis, targeting the national technical requirements for their classification in the category autoadens?vel and lightweight structural. The inclusion of mineral admixtures (metakaolin and bagasse ash of sugar cane), partial replacement of cement, pozzolanic activity and demonstrated maintenance of mechanical properties through the filler effect, a reduction of up to 76% of the nitrogen gas permeability in blend with 20% bagasse ash. All concretes had rheology (cohesion and consistency) suitable for self-adensability as well as strength and density inherent structural lightweight concrete without presenting phenomena of segregation and exudation / A busca por materiais alternativos de menor massa espec?fica, redu??o na transfer?ncia de calor e propaga??o do barulho, associado ? facilidade de manuseio e aplica??o em estruturas de concreto armado, representa grande desafio na formula??o e conhecimento do desempenho de concretos estruturais leves autoadens?veis, que tem tecnologia pouco difundida em n?vel nacional, e surge no cen?rio internacional como um material inovador e alternativo ao concreto convencional. Frente ao exposto, este trabalho se prop?s a estudar concretos estruturais leves autoadens?veis elaborados com duas gradua??es distintas de argila expandida associados ? inclus?o de aditivos plastificantes/superplastificantes e adi??es minerais de metacaulim e cinza de biomassa de cana-de-a??car. Tem-se ainda como objeto do estudo, a avalia??o da atividade pozol?nica das adi??es minerais e sua influ?ncia nas caracter?sticas de durabilidade dos concretos. As propriedades reol?gicas, f?sicas, mec?nicas e microestruturais, analisadas neste estudo, serviram como fundamenta??o na qualifica??o dos concretos leves autoadens?veis, visando ?s exig?ncias t?cnicas nacionais para sua classifica??o no quesito autoadens?vel e estrutural leve. A inclus?o das adi??es minerais (metacaulim e cinza de biomassa de cana-de-a??car), em substitui??o parcial do cimento, demonstrou atividade pozol?nica e manuten??o das propriedades mec?nicas atrav?s do efeito filler, apresentando redu??o de at? 76% da permeabilidade a g?s nitrog?nio na mistura com 20% de cinza de biomassa. Todos os concretos dosados apresentaram reologia (coes?o e consist?ncia) adequada para autoadensabilidade, bem como resist?ncia e massa espec?fica inerentes aos concretos estruturais leves, sem apresentar fen?menos de segrega??o e exsuda??o

Made available in DSpace on 2014-07-29T15:03:38Z (GMT). No. of bitstreams: 1 dissertacao janaina parte 1.pdf: 4357572 bytes, checksum: 40dbbd6f2f4cdbb3296717b82f972c80 (MD5) Previous issue date: 2007-08-27 / For the benefits of its properties in fresh state, self-compacting concrete (SCC) demands a high powder content in the composition, nearby 450kg/m³. The quarry dust, resultant material of the coarse aggregate production, can b considered as an economic and sustainable alternative for the development of the SCC. As well as the quarry dust, mineral additions, is used in conventional concretes and can also be used in the self-compacting concrete, with the same kind of benefits. Using the mix design for SCC developed by Tutikian (2004) a study for evaluation of the SCC mechanical properties were done, where natural sand had been partially replaced by quarry micaschist, granite and gneiss - and cement for silica fume, metakaolin and calcined clay pozolan. The test methods for fresh state used was Slump-flow (FURNAS, 2005a), U-Box (FURNAS, 2005b), Entrained air (NM 47, 2002) and Specific gravity (9833, 1997). Cylindrical test specimen 100x200 mm had been molded for tests - compressive strength (NBR 5739, 1994), modulus of elasticity (NBR 8522, 1984), splitting tensile strength (NBR 7222, 1994) and flexural strength (NBR 12142, 1991) -the age of 28 days. Samples using the mixture1: 4,5 had been analyzed by scanning electron microscope (SEM). The results show that it can be possible the use of different additions for the production of high quality SCC. We detach the small variability of the specific gravity, as well as the entrained air, wide presented low values. For concretes with same compressive strength, the values of modulus of elasticity had varied between 5 and 60% and the splitting tensile strength and flexural strength had been remained between 10 and 15% / Para atender suas propriedades no estado fresco, o concreto autoadensável (CAA) demanda uma grande quantidade de finos em sua composição, em média 450 kg/m³. Os finos de pedreira, material resultante do processo de britagem, surgem como alternativa econômica e sustentável no desenvolvimento do CAA. Além dos finos, adições minerais pozolânicas, muito utilizadas em concretos convencionais, podem ser utilizadas também no concreto auto-adensável, com os mesmos benefícios. Utilizando-se o método de dosagem para CAA proposto por Tutikian (2004), foi desenvolvido um estudo para avaliação das propriedades mecânicas do CAA, onde foram realizadas substituições parciais da areia natural por finos de pedreira micaxisto, granito e gnaisse e substituições parciais de cimento por sílica ativa, metacaulim e pozolana de argila calcinada. Os ensaios no estado fresco realizados foram Espalhamento (FURNAS, 2005a), Caixa U (FURNAS, 2005b), Teor de Ar (NM 47, 2002) e Massa Específica (NBR 9833, 1997). Corpos-de-prova cilíndricos com dimensões de 100x200 mm foram moldados para ensaios no estado endurecido resistência à compressão (NBR 5739, 1994), módulo de elasticidade (NBR 8522, 1984), tração por compressão diametral (NBR 7222, 1994) e tração na flexão (NBR 12142, 1991) na idade de 28 dias. Foram analisadas amostras das composições intermediárias (1:4,5) em microscópio eletrônico de varredura (MEV). Os resultados obtidos mostram ser possível a utilização de diferentes adições na produção de CAA s de qualidade. Destaca-se a pouca variabilidade das massas específicas, bem como dos teores de ar, que apresentaram valores baixos. Para concretos de mesma resistência à compressão, os valores obtidos para o módulo de elasticidade variaram entre 5 e 60% e as resistências à tração mantiveram-se entre 10 e 15%

O uso de fibra de aço como reforço no concreto tem sido objeto de várias pesquisas recentes. Com o surgimento do concreto autoadensável reforçado com fibras, a fluidez do concreto aumenta a possibilidade de orientação das fibras na etapa de concretagem, o que pode trazer alterações significativas no comportamento mecânico do concreto endurecido. O objetivo deste trabalho foi verificar a influência das condições de moldagem sobre a resistência residual pós-fissuração de elementos planos moldados com concreto autoadensável reforçados com fibra de aço. Também foi objetivo deste trabalho verificar previamente a combinação de ensaios reológicos com métodos convencionais para controle e caracterização do concreto autoadensável no estado fresco. A caracterização do concreto foi feita com reometria rotacional, caixa-L e espalhamento. Os resultados apontam que o estudo da reologia do concreto é desejável e a combinação dos ensaios de reologia com ensaios convencionais pode trazer mais informações sobre o efeito da adição de fibras. Foram realizados ensaios de punção de placas para avaliar o comportamento mecânico de elementos planos produzidos com concreto lançado em posições distintas. A confirmação da orientação preferencial das fibras como causa da diferença de comportamento foi realizada através de informações obtidas com os ensaios indutivo e Double Edge Wedge Splitting (DEWS) realizados em testemunhos extraídos de placas moldadas sob as mesmas condições. Além disso, comprovou-se que a orientação preferencial gerada pelas condições de lançamento do concreto pode influenciar significativamente na resistência pós-fissuração de elementos estruturais planos. / The use of steel fiber as reinforcement in concrete has been the subject of several recent studies. With the development of self-compacting fiber reinforced concrete, the fluidity of the material could increase the possibility of orientation of fibers during the casting process. That condition could bring significant changes in the mechanical behavior of hardened fiber reinforced concrete. The aim of this study was to investigate the influence of the conditions of casting on the post-cracking residual strength of flat elements molded with self-compacting concrete reinforced with steel fibers. It was also an objective of this work verify previously the combination of rheological tests with conventional methods in order to control and characterize the self-compacting concrete in the fresh state. The characterization of the concrete in fresh state was made with rotational rheometer, L-box and spreading tests. The results showed that the study of the concrete rheology is desirable and combination of rheological tests with conventional testing can provide more information about the effect of fiber addition. The evaluation of the mechanical behavior of flat elements produced under different positions of casting was conducted through test panels submitted to punching loading. The confirmation of the orientation of the fibers as a cause of the difference in the behavior was accomplished through information obtained from the inductive and DEWS tests performed on extracted cores of panels molded under the same conditions. Furthermore, the preferred orientation caused by the concrete flow significant influence on the post-cracking strength of the structural flat elements was shown. The tests carried out with extracted cores endorsed the conclusion that the cause of performance variation is fundamentally linked to the preferred orientation, which is a result of the casting procedure.

The theoretical part describes the properties of fine-grained admixtures and the ways how these admixtures modify concrete properties. There are also described ways to assemble grain curves in the range 0-1000 m. The practical part describes the properties of all the concrete components used for the tests. From the admixtures and cement, the individual grain curves were compiled. Curves were assembled in the first stage manually by using MS Excel. Subsequently, a simple program was developed based on the knowledge of composing grain curves, which automatically compiles the grain curve according to the given limits. The maximum cement replacement was set at 25% by weight. The physical and mechanical properties of the graded curves thus established were first verified on mortar mixtures where the workability, bulk density and strength were verified at the age 7, 28 and 90 days. In addition, the porosity of cement cement with mercury porosimetry has been verified for selected recipes. The acquired knowledge was subsequently applied to the concrete in the laboratory. Here the maximum cement compensation was set at 30%. In particular, concrete consistency over time, air content in the concrete and compresive strength of concrete at the age 3, 7, 28 and 90 days were verified. Verification was also carried out in practice on the optimization of self-compacting concrete. Mechanical properties have been retained for optimized recipe but there were financial savings and CO2 emissions reductions compare with the original recipe.

This thesis addresses numerical simulations of self-compacting concrete (SCC) castings and suggests a novel modelling approach that treats reinforcement zones in a formwork as porous media. As a relatively new field in concrete technology, numerical simulations of fresh concrete flow can be a promising aid to optimise casting processes and to avoid on-site casting incidents by predicting the flow behaviour of concrete during the casting process. The simulations of fresh concrete flow generally involve complex mathematical modelling and time-consuming computations. In case of a casting prediction, the simulation time is additionally significantly increased because each reinforcement bar occurring in succession has to be considered one by one. This is particularly problematic when simulating SCC casting, since this type of concrete is typically used for heavily reinforced structural members. However, the wide use of numerical tools for casting prediction in practice is possible only if the tools are user-friendly and simulations are time-saving. In order to shorten simulation time and to come closer to a practical tool for casting prediction, instead to model steel bars one by one, this thesis suggests to model zones with arrays of steel bars as porous media. Consequently, one models the flow of SCC through a reinforcement zone as a free-surface flow of a non-Newtonian fluid, propagating through the medium. By defining characteristic parameters of the porous medium, the influence on the flow and the changed (apparent) behaviour of concrete in the porous matrix can be predicted. This enables modelling of any reinforcement network as a porous zone and thus significantly simplifies and fastens simulations of reinforced components’ castings. Within the thesis, a computational model for SCC flow through reinforced sections was developed. This model couples a fluid dynamics model for fresh concrete and the macroscopic approach for the influence of the porous medium (formed by the rebars) on the flow. The model is implemented into a Computational Fluid Dynamics software and validated on numerical and experimental studies, among which is a large-scale laboratory casting of a highly reinforced beam. The apparent rheology of concrete within the arrays of steel bars is studied and a methodology to determine unknown input parameters for the porous medium is suggested. Normative tables defining characteristic porous medium parameters as a function of the topology of the rebar zone for different reinforcement cases are generated. Finally, the major contribution of this work is the resulting numerical package, consisting of the numerical solver and the parameter library. The thesis concludes on the ability of the porous medium analogy technique to reliably predict the concrete casting behaviour, while being significantly easier to use and far less time consuming than existing tools. / Die Arbeit behandelt die numerische Modellierung des Fließverhaltens von selbst-verdichtendem Beton (SVB) in bewehrten Schalungselementen. Die numerische Simulation des Fließens von Frischbeton kann eine vielversprechende Unterstützung bei der Optimierung von Befüllvorgängen sein, indem diese bereits im Vorfeld vorhergesagt werden. Die Simulation des Fließens von Frischbeton verwendet komplizierte mathematische Modelle und zeitintensive Rechenoperationen. Darüber hinaus wird die Simulationszeit für die Vorhersage des Füllvorgangs zusätzlich deutlich verlängert, weil aufeinanderfolgende Bewehrungsstäbe einzeln zu berücksichtigen sind. Das ist insbesondere für die Simulation von SVB ein entscheidendes Problemfeld, da SVB oft gerade für hochbewehrte Bauteile verwendet wird. Dennoch ist ein weitreichender Einsatz von numerischen Hilfsmitteln bei der Vorhersage von Füllprozessen nur denkbar, wenn die Anwenderfreundlichkeit und eine Zeitersparnis gewährleistet werden können. Um die Simulationszeit zu verkürzen und näher an eine anwenderfreundliche Lösung für die Vorhersage von Füllprozessen zu kommen, wird als Alternative zur einzelnen Modellierung aller Stahlstäbe in dieser Arbeit vorgeschlagen, Zonen mit Bewehrungsstäben als poröse Medien zu modellieren. Infolgedessen wird das Fließen von SVB durch bewehrte Zonen als Strömung eines nicht-Newton’schen Fluides durch ein poröses Medium betrachtet. Durch die Definition charakteristischer Parameter des porösen Mediums kann das veränderte Verhalten des Betons in der porösen Matrix vorhegesagt werden. Dies ermöglicht die Modellierung beliebiger Bewehrungszonen und vereinfacht und beschleunigt folglich die numerische Simulation bewehrter Bauteile. Im Rahmen der Arbeit wird ein Rechenmodell für das Fließverhalten von SVB durch bewehrte Schalungszonen entwickelt. Das Modell verkoppelt das Strömungsverhalten von Beton mit dem makroskopischen Ansatz für den Einfluss von porösen Medien, welche in diesem Fall die Bewehrungsstäbe ersetzen. Das entwickelte Modell wird in eine CFD-Software implementiert und anhand mehrerer numerischer und experimenteller Studien validiert, darunter auch ein maßstabsgetreues Fließexperiment eines hochbewehrten Balkens. Darüber hinaus wird die scheinbare Rheologie des Betons innerhalb der Anordnung der Stahlstäbe untersucht und daraus eine Methode zur Bestimmung unbekannter Parameter für das poröse Medium vorgeschlagen. Es werden hierfür auch normative Tabellen generiert, die die charakteristischen Eigenschaften der porösen Medien für unterschiedliche Bewehrungsanordnungen abbilden. Zuletzt ist der Hauptbeitrag dieser Arbeit das resultierende Numerikpaket, bestehend aus dem numerischen Solver einschließlich des implementierten Modells sowie der Parameterbibliothek. Im Abschluss werden die Verlässlichkeit der Vorhersage von Füllvorgängen durch die Analogie zu porösen Medien erörtert sowie Schlussfolgerungen zur deutlichen Ersparnis an Aufwand und Zeit gegenüber herkömmlichen Methoden vorgenommen.

Gegenstand der Arbeit ist die Entwicklung eines numerischen Stoffgesetzes, welches die materialspezifischen Besonderheiten Selbstverdichtender Betone in jungem Alter erfasst. Durch das erhöhte Schwindmaß eines Selbstverdichtenden Betons innerhalb der ersten zwölf Stunden können Dehnungszustände hervorgerufen werden, welche zu Schädigungen führen, die von den einschlägigen Normen bisher noch nicht erfasst wurden. Im Zuge des Forschungsprojektes „Selbstverdichtender Beton im Untertagebau“ konnten Erkenntnisse über das materialspezifische Verhalten bei konstanten Umgebungsbedingungen erlangt werden. Diese Ergebnisse wurden mit übertägig gewonnen Daten verglichen, um eine klare Abgrenzung zu einem normalen Rüttelbeton zu ziehen. Im weiteren Verlauf wurden die Ergebnisse zur Kalibrierung einer numerischen Simulation herangezogen. Damit kann nun, in Abhängigkeit der relativen Luftfeuchtigkeit und der Bauteilgröße, das Dehnungsverhalten eines SVB in jungem Alter realitätsnah beschrieben werden.:Inhaltsverzeichnis Vorwort II Kurzfassung III Abstract IV 1. Einleitung 1 1.1 Problemstellung 1 1.2 Stand der Erkenntnis 4 1.3 Zielsetzung 8 2. Mechanische Eigenschaften Selbstverdichtender Betone 12 2.1 Rheologische Grundlagen 12 2.1.1 Mischungszusammensetzung für den Einsatz Untertage 12 2.1.2 Kinetik des Erstarrens 17 2.1.3 Frisch- und Festbetoneigenschaften 20 2.1.4 Mischungsentwurf 22 2.2 Feuchte- und Wärmetransport 24 2.2.1 Hydratationsverhalten 24 2.2.2 Feuchtetransport und Speicherung 28 2.2.3 Numerische Umsetzung der Feuchte- Wärmekopplung 32 2.2.4 Finite Element Formulierung und Umsetzung mit Abaqus 35 2.3 Mathematische Formulierung 40 2.3.1 Thermische Leitfähigkeit 40 2.3.2 Hygrische Leitfähigkeit 42 2.3.2.1 Hygrische Transportvorgänge bei Änderung der Umgebungsfeuchte 43 2.3.2.2 Hygrische Transportvorgänge anhand von Temperaturveränderungen 46 2.4 Lastunabhängige Verformungen von Beton 47 2.4.1 Temperatureffekte 47 2.4.2 Feuchteffekte 49 3. Experimentelle Untersuchungen 51 3.1 Ergebnisse der Laborversuche 51 3.1.1 Zug- und Druckfestigkeiten 51 3.1.2 Hydratationsverhalten 55 3.1.3 Feuchtemessungen an Schwindrinnen 57 3.1.4 Schwindverhalten aus Laborversuchen 62 3.2 Untersuchungen am Großversuchsstand 65 3.2.1 Einrichtung des Versuchsstandes 65 3.2.2 Fördertechnologie 68 3.2.3 Schalungsdrücke 69 3.2.4 Hydratationsverhalten und Lastunabhängige Verformungen 70 3.3 Versuchsergebnisse am Großversuchsstand 70 3.3.1 Hydratation und Wärmefreisetzung 70 3.3.2 Schalungsdrücke 74 3.3.3 Schwind- und Temperaturdehnungen 76 3.3.3.1 Schwindrinnen 76 3.3.3.2 Tunnelbauwerk 78 3.4 Rissbildung am Bauwerk 80 3.4.1 Übersicht zu gängigen Risskonzepten 80 3.4.2 Methodenvalidierung der Risskriterien 83 4. Numerische Berechnungen 87 4.1 Numerische Grundlagen 87 4.1.1 Zwangsspannungen infolge Hydratation 87 4.1.1.1 Instationäre Wärmeleitungsprobleme 89 4.1.1.2 Berechnung von Verschiebungsfeldern 90 4.1.2 Thermisch-hygrische Dehnungen 92 4.2 Numerische Detailuntersuchungen und Modellparameter 94 4.2.1 Konstruktive Details des Modells 95 4.2.2 Bewehrungselemente 97 4.2.3 Ermittlung der benötigten Parameter 99 4.3 Vergleichsberechnungen 103 4.3.1 Hydratationswärmeentwicklung 103 4.3.2 Thermisch-hygrische Kopplung 106 4.4 Berechnungsergebnisse 109 4.4.1 Schwindrinne 110 4.4.1.1 Temperaturentwicklung und Trocknungsverhalten 110 4.4.1.2 Schwinddehnungen 113 4.4.1.3 Längenänderungen infolge unterschiedlicher Umgebungsfeuchten 117 4.4.2 Untertägiges Tunnelbauwerk 119 4.4.2.1 Temperaturentwicklung und Trocknungsverhalten bei hohen Luftfeuchtigkeiten 119 4.4.2.2 Spannungsentwicklung infolge Zwang 122 4.4.3 Rissbildung in jungem Alter 126 4.4.3.1 Kritischer Hauptspannungsraum und mögliche Rissbreiten 126 4.4.3.2 Beanspruchungen der Bewehrung 131 4.4.4 Abhängigkeiten der Dehnungsverteilung und Rissbreite von Selbstverdichtenden Betonen in jungem Alter 134 5. Zusammenfassung und Ausblick 139 Literaturverzeichnis 143 Abkürzungsverzeichnis 151 Abbildungsverzeichnis 152 Tabellenverzeichnis 156 Anhangsverzeichnis 157

Idag är intresset för högpresterande betong (HPB) växande runt om världen då fördelarna är många, eftersom slankare, tätare, starkare och lättare konstruktioner kan tillverkas.   Detta examensarbete handlar om materialförsök och modellering för en typ av HPB som ska användas i husbyggnation. Arbetet inleddes med materialförsök i färskt tillstånd, där god gjutbarhet och konsistens eftersträvades. Utgångspunkten var från ett grundrecept med två olika ballastsorter (slaggballast med flygaska och krossballast från asfaltindustrin med silikastoft), vilka namngavs till pilotförsök 1 och pilotförsök 2. Vidare valdes pilotförsök 1 att provas i hårdnat tillstånd då det visades att det var mer ekonomiskt lönsam eftersom ballasten inte behövde siktas, lägre vct tillhandhölls och att flygaskan som användes i pilotförsök 1 är billigare än silikastoft som användes i pilotförsök 2. Resultaten efter 28 dygn för de materialförsök som utfördes i hårdnat tillstånd var: Tryckhållfasthet; 141,9 MPa Draghållfasthet; 7,0 MPa Böjdraghållfasthet; 10,0 MPa Elasticitetsmodul; 46,4 GPa Krympning efter 56 dygn; 0,5 ‰ Samtliga försök utfördes enligt svenska standarder (SS).   Dessutom vidareutvecklas och förbättrades ett redan arkitektoniskt gestaltat Attefallshus ur ett konstruktions- och hållbarhets perspektiv, där fokus låg på transport- och produktionsförutsättningar. Det resulterade i att horisontella avstyvningar tillades i väggelementen för att öka styvheten och minska risken för brott under transport och produktion. Huset är tänkt att produceras med prefabriceringsteknik. Avslutningsvis modellerades ett oarmerat väggelement i FE-programmet Abaqus under linjärt elastiskt tillstånd. Vid modelleringen användes de materialparametrar som erhölls från materialförsöken.  Det resulterade i att deformationer, spänningar samt knäcknings- och bucklingsanalys kunde redas ut. Väggelementen i huset klarar normenliga laster enligt modelleringen. / Nowadays the interest for high-performance concrete (HPC) is growing around the world as the benefits are many, for example slender, denser, stronger and lighter structures can be manufactured.   This thesis is about material and design experiments for a type of HPC to be used in building construction. The work began with materials experiments in the fresh state, where good workability and consistency were tried to be obtained. The starting point was from a basic recipe with two different aggregate types (slag aggregates with fly ash and crushed aggregates from the asphalt industry with silica fume), which were named as the pilot test 1 and the pilot test 2. Furthermore pilot test 1 was elected to be tested in hardened state as it turned out to be more economically profitable, had a lower vct, and that the flyash was cheaper than the silica fume used in the pilot test 2. The results after 28 days when the materials experiments were carried out in the hardened state were: Compressive strength; 141,9 MPa Tensile strength; 7,0 MPa Flexural strength; 10,0 MPa Modulus of elasticity; 46,4 GPa Shrinkage after 56 days; 0,5 ‰ All experiments were performed according to Swedish standards SS.   Moreover, an existing architecturally portrayed Attefallshus was further developed and improved from a design and a strength perspective that mainly focused on transport and production. It resulted in the horizontal stiffeners to be installed in the wall elements to increase rigidity and reduce the risk of breakage during shipment and production. The house is intended to be built with prefabrication technology. Finally the unreinforced wall elements were modeled in the FE program ABAQUS under linear elastic condition. During modeling the material parameters obtained from material tests were used in the model. Consequently, strain, stress and buckling analysis could be made. The wall sections in the house met the norm loads according to the model.