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Previous issue date: 2016-03-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Fire situations in reinforced concrete structures’ building are common because the
widespread use of structural material. However, the analysis and measurement of
the damage caused by these claims still need more details and the relationship
between the variables that influence the structural capacity should be examined
together. Therefore, this work presents the analysis of the structural behavior of
reinforced concrete beams subjected to high temperatures with parameters of
coatings and water-cement ratio analyzed together with the temperature levels
through the statistical experimental design 2³ in central composite rotational design
(CCRD). The factorial design was used from the selection of variables, the definition
of the levels and the post-processing data. Thus defined the materials and their
proportions, were made 48 beams reduced with different coatings and water-cement
factors. After the curing process and drying, the beams were subjected to different
levels of temperature and analyzed the variation in the capacity of the beams
subjected to simple bending through its curve of load x deflection. An analogous
procedure was performed for 29 specimens were tested to simple compression. With
samples of the specimens and the beams also were conducted thermogravimetry
tests, scanning electron microscopy and diffraction of x-rays intended to detect the
effect on the cement hydration products and relate them with the loss of resistant
capacity. At the end, comparing statistical and microstructural results, it was found
the predominant influence of the variable factors water / cement and that there is
intersection between w/a ratio and temperature at which concrete gains strength and
has its accelerated hydration process in the formation of portlandite and tobermorite
detected. The findings open the way for discussion of the protection of structures
under fire situation by controlling water-cement ratio.Fire situations in reinforced concrete structures’ building are common because the
widespread use of structural material. However, the analysis and measurement of
the damage caused by these claims still need more details and the relationship
between the variables that influence the structural capacity should be examined
together. Therefore, this work presents the analysis of the structural behavior of
reinforced concrete beams subjected to high temperatures with parameters of
coatings and water-cement ratio analyzed together with the temperature levels
through the statistical experimental design 2³ in central composite rotational design
(CCRD). The factorial design was used from the selection of variables, the definition
of the levels and the post-processing data. Thus defined the materials and their
proportions, were made 48 beams reduced with different coatings and water-cement
factors. After the curing process and drying, the beams were subjected to different
levels of temperature and analyzed the variation in the capacity of the beams
subjected to simple bending through its curve of load x deflection. An analogous
procedure was performed for 29 specimens were tested to simple compression. With
samples of the specimens and the beams also were conducted thermogravimetry
tests, scanning electron microscopy and diffraction of x-rays intended to detect the
effect on the cement hydration products and relate them with the loss of resistant
capacity. At the end, comparing statistical and microstructural results, it was found
the predominant influence of the variable factors water / cement and that there is
intersection between w/a ratio and temperature at which concrete gains strength and
has its accelerated hydration process in the formation of portlandite and tobermorite
detected. The findings open the way for discussion of the protection of structures
under fire situation by controlling water-cement ratio. / Situações de incêndio em edificações com estruturas de concreto armado são
comuns, dado o vasto uso estrutural do material. Entretanto, a análise e mensuração
dos danos causados por esses sinistros ainda carecem de pormenorização e a
relação entre as variáveis que influenciam na capacidade resistente das peças
estruturais devem ser analisadas conjuntamente. Assim sendo, este trabalho
apresenta a análise do comportamento estrutural de vigas de concreto armado
submetidas às altas temperaturas com parâmetros de cobrimento e fator águacimento
analisados conjuntamente com os níveis de temperatura através do
planejamento experimental estatístico 2³ em delineamento composto central
rotacional (DCCR). O planejamento fatorial foi utilizado desde a seleção das
variáveis estudadas, a definição dos níveis e o pós-processamento dos dados.
Assim, definidos os materiais e suas proporções (dosagem), foram confeccionadas
48 vigas reduzidas com diferentes cobrimentos e fatores água-cimento. Após o
processo de cura e secagem, as vigas foram submetidas a distintos níveis de
temperatura e analisou-se a variação na capacidade resistente das peças
submetidas à flexão simples através da sua curva de carga x deflexão.
Procedimento análogo foi efetuado para 29 corpos-de-prova que foram ensaiados à
compressão simples. Com amostras dos corpos-de-prova e das vigas, foram
realizados ainda ensaios de termogravimetria, microscopia eletrônica de varredura e
difração de raios-x objetivando detectar o efeito causado nos produtos de hidratação
do cimento e relacioná-los com a perda da capacidade resistente das peças. Ao
cabo, comparando resultados estatísticos e microestruturais, verificou-se a influência
preponderante da variável fator água / cimento. Foi detectada uma faixa de
interseção entre a/c e temperatura para a qual o concreto ganha resistência e tem
seu processo de hidratação acelerado na formação da portlandita e tobermorita. As
conclusões abrem caminho para discussão a respeito da proteção de estruturas sob
situação de incêndio mediante o controle do fator água / cimento.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede.biblioteca.ufpb.br:tede/8880 |
| Date | 28 March 2016 |
| Creators | Souza, Leovegildo Douglas Pereira de |
| Contributors | Azeredo, Givanildo Alves de |
| Publisher | Universidade Federal da Paraíba, Programa de Pós-Graduação em Engenharia Civil e Ambiental, UFPB, Brasil, Engenharia Cívil e Ambiental |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFPB, instname:Universidade Federal da Paraíba, instacron:UFPB |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -5212314370655042468, 600, 600, 600, 600, -6802672734029945274, -6274833215046395772, 3590462550136975366 |
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