Um modelo para previsão da viscosidade mínima de suspensões cerâmicas

Pileggi, Rafael Giuliano; Studart, André R.; Pandolfelli, V. C.

doi:10.1590/s0366-69132000000300008

Cited by 4 publications

(2 citation statements)

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“…Flatt and Bowen [18] restricted to Van der Walls the forces for modeling the yield stress of ceramic suspensions, which is inversely proportional to the inter particle separation (1/IPS 2 ). Pileggi et al 2000 [19] presents the concept of particle crowding index (PCI), which relates the inter-particle separation (IPS) and the diameter of particles. This index presented a direct relationship with the viscosity of ceramic suspensions.…”

Section: Resultsmentioning

confidence: 99%

Effect of nano-silica on Portland cement matrix

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Repette

2019

Rev. IBRACON Estrut. Mater.

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ResumoThe use of nano-particles is a current trend that may play an important role for improving the mechanical performance of Portland cement. The aim of this study is to evaluate the effect of nano-silica on Portland cement matrix. The particle size distribution of Portland cement matrix was modified by the incorporation of 11, 6.2, 3.1, 1.7, 0.85 and 0.42 wt.% of nano-silica. The water demand and the consumption of dispersant were adjusted, and the rheological properties of suspensions were analyzed through rotational rheometry. The mechanical performance of studied mixtures was evaluated by the compressive strength. The pore size distribution was measured by mercury intrusion porosimetry (MIP), and the hydration was analyzed through X-ray diffractometry. The rheological behavior presented a considerable changed, as a consequence of high specific surface area of nano-particles. The optimum content of nano-silica, or the smaller quantity of nano-particles, that leads to the maximum strength gain, varied according to the water to solids ratio. An increasing on the hydration and a pore refinement were obtained due to the use of silica nanoparticles. The particle's packing and the pozzolanic reaction were the two main effects of nano-silica on the microstructure of Portland cement matrix.Keywords: rheology, compressive strength, mercury intrusion porosimetry, X-ray diffraction.Palavras-chave: reologia, resistência à compressão, porosimetria de intrusão de mercúrio, difração de raios-X.

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Section: Resultsmentioning

confidence: 99%

Effect of nano-silica on Portland cement matrix

Mendes

Repette

2019

Rev. IBRACON Estrut. Mater.

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“…Métodos reológicos de medição de propriedades de suspensões concentradas em reômetros rotacionais devem ser explorados, como rampa de tensão ou taxa de cisalhamento, ensaio de taxa de cisalhamento constante, fluência e recuperação e ensaios oscilatórios de varredura de amplitude e tensão. Diversos modelos reológicos foram propostos que se dedicam ao entendimento e previsão das propriedades reológicas com a concentração de sólidos, como modelo de Eistein, Krieger-Dogherty, Quemada (DÖRR; SADIKI; MEHDIZADEH, 2012) ou mais recente como o modelo de YODEL (FLATT; BOWEN, 2006) de previsão de valores de tensão de escoamento e o modelo de Interferência (OLIVEIRA et al, 2000;PANDOLFELLI, 2000) de previsão de viscosidade considerando tamanho de partículas, a distância que as separa e quantidade de material presente.…”

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