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Título: MECHANICAL BEHAVIOR AND DAMAGE EVOLUTION OF FIBER REINFORCED CONCRETE UNDER FLEXURAL FATIGUE LOADING FOR STRUCTURAL APPLICATIONS
Autor: VITOR MOREIRA DE ALENCAR MONTEIRO
Colaborador(es): FLAVIO DE ANDRADE SILVA - Orientador
DANIEL CARLOS TAISSUM CARDOSO - Coorientador
Catalogação: 11/ABR/2024 Língua(s): ENGLISH - UNITED STATES
Tipo: TEXT Subtipo: THESIS Menção Honrosa - Prêmio Capes de Tese - Edição 2024 - CAPES
Notas: [pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio.
[en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio.
Referência(s): [pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=66414&idi=1
[en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=66414&idi=2
DOI: https://doi.org/10.17771/PUCRio.acad.66414
Resumo:
This doctoral thesis originates from the research project Aneel PD-0394- 1905/2019, carried out through a collaboration between Furnas and PUC-Rio. The main objective of this extensive research project is the development of fiber reinforced concrete for distinct structural application which are subjected to continuous flexural fatigue loading along their useful life, such wind tower endeavors, concrete pavements and bridge elements. The addition of fibers in the concrete mix has the potential to mitigate the mechanical deterioration along the continuous load cycles, enhancing, as a consequence, the durability and the fatigue life of the cited concrete structural elements. Throughout this doctoral thesis, the mechanical degradation of fiber reinforced concrete under fatigue is carefully analyzed, starting from the fiber scale with pull-out tests and going up to the structural scale through large-scale fatigue mechanical tests. The first stage of this study involves an analysis of the mechanical behavior of fiber reinforced concrete under fatigue loading. The material fatigue life is examined using different statistical models, which allow evaluating material failure based on a failure probability. Fatigue pull-out tests help explain, at the fiber-matrix interface scale, how the prisms rupture under cyclic loading. A second phase of this work demonstrates the mechanical degradation of reinforced structural beams under fatigue and the impact of fiber addition on key concerned parameters. The addition of fiber reinforcement causes a redistribution of stresses in the tension zone of the structural element, reducing the deformations of the longitudinal rebar and mitigating the mechanical degradation of reinforced concrete in terms of curvature, displacement and stiffness. Furthermore, fiber addition significantly improves the bond between the steel bar and the surrounding concrete matrix, a key factor in explaining the enhanced mechanical response of the structure under fatigue, as studied in this doctoral thesis through rebar pull-out tests. Finally, a new analytical solution was developed to assess the mechanical degradation of fiber reinforced concrete prisms under fatigue loads. The proposed analytical curves successfully fit the experimental results analyzed in this work. The addition of fibers showed great potential in reducing the mechanical degradation of reinforced concrete structures subjected to cyclic loading. The stress redistribution in the tension zone, caused by the fibers, promotes greater stiffness of the structure under fatigue, improves the bond with the reinforcement and enhances the ability to withstand fatigue cycles over time. Therefore, the observed enhancement of mechanical properties through fiber reinforcement can ensure a longer service life for reinforced concrete structures.
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