Análise da estrutura porosa de materiais cimentícios por meio da interação e associação de técnicas avançadas de caracterização

• Autor(a) principal: Hilário, Hanaelly Garcia do Carmo
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10407
• topic: 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); ENGENHARIA CIVIL::CONSTRUCAO CIVIL

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.