Previsão da vida útil de concreto armado de alta resistência com adição de metacaulim e sílica ativa em ambientes marinhos

Medeiros, Marcelo Henrique Farias de; Gobbi, Andressa; Groenwold, J. A.; Helène, Paulo

doi:10.1590/s0370-44672013000100008

Cited by 8 publications

(6 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…High reactivity metakaolin was used as cement partial replacement in the contents of 4, 8 and 12 % -being the intermediate value (8%) the recommended by the manufacturer and commonly used in the region. Additionally, this value is close to 10%, a content found by some studies to be beneficial for mechanical and durability properties of concrete [11,19,34,35]. The superior (12%) and inferior (4%) values were adopted for comparison.…”

Section: Methodsmentioning

confidence: 58%

Analysis of the chloride diffusion coefficients by different test methods in concrete mixtures containing metakaolin and high-slag blast-furnace cement

et al. 2019

View full text Add to dashboard Cite

This study aims to evaluate the chloride diffusion coefficient and the service life (SL) of concretes containing metakaolin and high-slag blast-furnace cement (HSBFC). Accelerated methods of chloride ion diffusion and migration (RCPT, RMT, BDT and multiregime test method) were used. To produce the specimens, HSBFC resistant to sulphates (CPIII 40 RS) was partially replaced by metakaolin in the contents of 4%, 8% and 12%. Statistical analysis was performed by means of Analysis of Variance (ANOVA) and Tukey's Test to the chlorides diffusion coefficients obtained from different test methods. Similarity between diffusion by immersion (BDT) and non-stationary migration test (RMT and multiregime method) results was noted, however, with differences regarding to the stationary regime. The average diffusion coefficient obtained in the concrete specimens with 8 and 12% metakaolin as HSBFC partial replacement was 40-45 % lower than the reference mixture, providing an SL increase of approximately 70%. The most efficient metakaolin content obtained for overall mechanical and durability properties of concrete was 8%. This study also showed that HSBFC partial replacement by metakaolin can be beneficial even at later ages, as in 150 days.

show abstract

Section: Methodsmentioning

confidence: 58%

Analysis of the chloride diffusion coefficients by different test methods in concrete mixtures containing metakaolin and high-slag blast-furnace cement

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Já em pesquisa realizada por Medeiros et al (2013), o uso da sílica ativa em substituição ao cimento, reduziu a carga passante no ensaio de migração de cloretos em 85-88% e, portanto, evidenciando a grande eficiência da sílica ativa para produzir concretos duráveis em regiões altamente influenciadas pela maresia. Segundo o autor, o tempo de vida útil de serviço aumentou em 440% quando houve adição da sílica ativa.…”

Section: Resultados E Discussõesunclassified

Caracterização mecânica e reológica de concretos com resíduos de madeira e sílica ativa

Massarotto¹,

Júnior

Dalosto

2019

View full text Add to dashboard Cite

O concreto é um dos materiais de construção mais utilizados no mundo, mas devido ao seu processo de produção, tem um grande impacto ambiental pelas atividades relacionadas a fabricação e extração de matéria-prima. A presente pesquisa tem por objetivo analisar os efeitos da incorporação dos resíduos de madeira e sílica ativa no concreto a partir da substituição parcial da areia (agregado miúdo) por resíduos de serragem e do cimento Portland por sílica ativa, para produção de concreto com propriedades mecânicas e reológicas satisfatórias. Desta forma, foram produzidas amostras de concreto com substituição parcial de areia por serragem em 5%, 7,5% e 10% do peso total da areia na mistura de referência e, também, amostras de concreto com as mesmas porcentagens de substituições, porém, conjuntamente, com substituição parcial do cimento por sílica ativa em 10% do peso total de cimento. Após a fabricação das seis amostras, foram realizados ensaios de slump test, de absorção por capilaridade e ensaio de compressão simples, com intuito de verificar as variações nas propriedades reológicas e mecânicas em relação ao concreto de referência, constituído por mistura convencional com agregados de areia, brita e cimento. Os resultados apontam que o uso de serragem na matriz cimentícia gera redução da densidade de concreto, funcionando como aditivo retardador natural de pega e, também, produz um concreto com porosidade e propriedades mecânicas satisfatórias em relação ao concreto de referência. Além disso, a sílica ativa controlou a trabalhabilidade e a absorção de água por capilaridade quando comparado ao concreto de referência. Conclui-se, portanto, que os as referidas substituições geram efeitos benéficos no comportamento reológico e mecânico do concreto quando comparado com a mistura de referência.

show abstract

“…Due to the exposed, it was proposed the Equation 1 to derive empirically the chloride diffusion coefficient estimate using the results of total charge passed related to the RCPT (ASTM C1202). This equation was adopted by other authors such as Helene and Medeiros [25] and Andrade and Whiting [26].…”

Section: Chloride Diffusion Coefficientmentioning

confidence: 99%

Evaluation of the chloride penetration and service life of self-healing concretes activated by crystalline catalyst

Helène¹,

Guignone

Vieira

et al. 2018

Rev. IBRACON Estrut. Mater.

View full text Add to dashboard Cite

The main cause of concrete structures deterioration is related to the resistance against the penetration of aggressive agents. Aiming at increase the impermeability and reduce the diffusivity of concrete elements, making it less susceptible to the ingress of chloride ions, the use of crystalline catalyst emerges as a good alternative. Its mechanism of autogenous healing enhances the natural pore-filling process of concrete. The aim of this study is to investigate the influence of the use of crystalline catalyst on the chloride ions penetration and service life prediction of concrete. For the concrete mixtures production, it was used blast-furnace slag blended cement, three different water/cement (w/c) ratios (0.45; 0.55; 0.65), with and without crystalline catalyst, totaling six different mixtures. The concrete specimens were cured in a moist chamber and tested at 28 and 91 days. It was performed tests of compressive strength, rapid chloride permeability (ASTM C1202:12), and silver nitrate colorimetric indicator. The results show that, compared to the reference mixture, the use of crystalline catalyst conserved the compressive strength and reduced the chloride ions penetration up to 30%, increasing service life up to 34%.

show abstract

Previsão da vida útil de concreto armado de alta resistência com adição de metacaulim e sílica ativa em ambientes marinhos

Cited by 8 publications

References 9 publications

Analysis of the chloride diffusion coefficients by different test methods in concrete mixtures containing metakaolin and high-slag blast-furnace cement

Analysis of the chloride diffusion coefficients by different test methods in concrete mixtures containing metakaolin and high-slag blast-furnace cement

Caracterização mecânica e reológica de concretos com resíduos de madeira e sílica ativa

Evaluation of the chloride penetration and service life of self-healing concretes activated by crystalline catalyst

Contact Info

Product

Resources

About