Análise da estrutura porosa de materiais cimentícios por meio da interação e associação de técnicas avançadas de caracterização
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Data
2019-12-20
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Universidade Federal de Goiás
Resumo
Cementitious materials such as concretes, mortars and pastes are naturally porous and they
have a complex internal pore structure. This porosity has determining effects on the
mechanical properties and durability of structures. Therefore it’s required a better
understanding of the porous structure. This understanding is based on the use of techniques
for measuring the porosity of cementitious materials, further analysis and interpretation of
results and techniques. Thus, the objective of the present work was to analyze whether there
is correlation, parallelism and complementation between the following advanced
characterization techniques: Mercury Intrusion Porosimetry (MIP), Nitrogen Adsorption (BET),
Nuclear Magnetic Resonance (NMR) and X-ray Computed Microtomography (μCT) when used
for porosity measurement in cementitious matrices. As well as assess the responsiveness and
sensitivity of these techniques through their results and output variables in relation to the
various situations proposed in the dosage. The methodological steps taken to reach the
objective include: the complete characterization of the materials used, the dosage of five
different concretes (REF 0.40, REF 0.55, 0.55/10MK, 0.55/9SA1NS and REF 0.70 ), tests with
concretes, such as: slump test, incorporated air content, compressive strength and modulus
of elasticity, tests on pastes, such as: DRX; and tests on mortars: MIP, BET, NMR and μCT,
for porosity studies. The results show that, depending on the range and structure of the
pores, the results of BET, MIP, NMR and μCT may be more or less representative. The NMR
tests captured a higher total porosity for the studied mortars. The NMR results also have good
correlations with all other techniques studied, either with the whole sample scope or
considering only the reference mortars. The same statement can be made for the BET
technique. NMR and μCT techniques together occupy the largest pore diameter range and
they have a number of similarities, in this way it is concluded that the combination of the two
is the most viable.
Descrição
Palavras-chave
Ressonância Magnética Nuclear (RMN) , Concreto , Porosidade , Porosimetria por Intrusão de Mercúrio (PIM) , Adsorção de Nitrogênio (BET) , Microtomografia Computadorizada de Raios X (μCT) , Nuclear Magnetic Resonance (NMR) , Concrete , Porosity , Mercury Intrusion Porosimetry (MIP) , Nitrogen Adsorption (BET) , X-ray Computed Microtomography (μCT)
Citação
HILÁRIO, H. G. C. Análise da estrutura porosa de materiais cimentícios por meio da interação e associação de técnicas avançadas de caracterização. 2019. 122 f. Dissertação (Mestrado em Engenharia Civil) - Universidade Federal de Goiás, Goiânia, 2019.