Título: | EXPLORING THE INFLUENCE OF HIGH TEMPERATURE AND PRESSURE ON GEOPOLYMER PROPERTIES | ||||||||||||
Autor: |
UMBERTO CASSARA DE C S SICILIANO |
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Colaborador(es): |
FLAVIO DE ANDRADE SILVA - Orientador ANA CAROLINA CONSTANCIO TRINDADE - Coorientador |
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Catalogação: | 13/MAI/2024 | Língua(s): | ENGLISH - UNITED STATES |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||
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. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=66643&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=66643&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.66643 | ||||||||||||
Resumo: | |||||||||||||
Geopolymers (GPs), classified as polysilicate-aluminates, represent
inorganic polymers or chemically bonded ceramics with diverse applications
determined by the Si:Al atomic ratio, including: fire-resistant components, sealants,
mortar for reinforcing beams and oil well plugging. The exploration of GPs under
varying temperature and/or pressure conditions gained momentum post-2001. The
addition of chamotte into GP formulation only occurred in 2014, followed by
subsequent investigations into the impact of adding carbon nanotubes and nanoclay
a year later. The primary objective of this thesis was to assess the compressive
strength of plain potassium-based GP cured at temperatures and pressures of up to
200 degrees C and 70 MPa, respectively. This evaluation included comparative analysis
with microstructural characterizations such as porosimetry and thermogravimetry.
Initially, the study evaluated the reaction mechanisms of different GP formulations
and determined the effects of alkali leaching on strength evolution under diverse
curing conditions (dry and saturated). The results identified the K-waterglass
composition with SiO2/K2O=1.53 and H2O/K2O=8.69 as presenting rapid strength
gain, low leachability, and was thus selected. Curing temperature significantly
impacted on the final properties, demonstrating a notable 144% improvement in
compressive strength at 50 degrees C, and an additional 37 percent improvement at 50 degrees C under
20 MPa, attributed to enhanced microstructural densification. The thesis also
explored the effect of adding micrometric (chamotte) and nanometric (nano-metakaolin, nanoclay and carbon nanotubes) particles under extreme curing
conditions (150 degrees C and 40 MPa). Preliminary results indicated satisfactory
dispersion of carbon nanotubes using a simple, low-energy technique. Individual
additions contributed to GP performance improvement, yet hybrid additions
surpassed any separate addition results, yielding a formulation with enhanced
reactivity. Under 150 degrees C curing, GP with hybrid additions exhibited a remarkable
350 percent improvement in mechanical properties compared to plain GP. Under 40 MPa
pressure, the mechanical performance was minimally affected by hybrid additions,
confirming their efficacy in achieving the desired properties for high-temperature
and pressure applications, including pore refinement, increased flexural strength,
and reduced porosity.
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