Interaction of silica fume with calcium hydroxide solutions and hydrated cement pastes

Mitchell, David R. G.; Hinczak, I; Day, Rebecca

doi:10.1016/s0008-8846(98)00133-1

Cited by 115 publications

(56 citation statements)

References 8 publications

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“…This is supported by the finding from the light-optical micrograph and Raman spectra which showed that the CH and CSH phases are identified at the outer area, i.e., points A and D, whilst the unhydrated amorphous SiO 2 is identified in the inner point B. In addition, this deduction can be further confirmed by the literature which showed that the reactions between SF and CH will be retarded because of the formation of the CSH layer on the surface of SF agglomerate, which can prohibit the further reactions (Mitchell, Hinczak, & Day, 1998).…”

Section: Characterisation Of a 6-month Sf Blended Paste With Raman Spsupporting

confidence: 52%

Application of Raman Spectroscopy for Tracing the Status of Silica Fume in Cementitious Materials

Yue¹,

Bai²,

Wang³

2016

Proceedings of the 5th International Conference on the Durability of Concrete Structures

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Silica fume (SF) is an important component for manufacturing high performance concrete (HPC), owing to its superb pozzolanic reactivity and physical filling effects. However, application of SF in concrete may cause potential hazards issues. Although using SF in slurry form can somehow reduce the potential biotoxicity, the long-term stability and status of the SF particles within cementitious materials is still uncertain. In the current study, attempts were made to use Raman spectroscopy as an innovative alternative technique for tracing and identifying the status of SF both in its original SF slurry and in a 6-month-old hydrated cement paste. Light-optical microscope was also used to examine the morphology of the SF particles in the aforementioned samples. The results showed that under Raman spectroscopy, the various components of the SF in slurry, such as amorphous silica, silicon crystal, and carbon, were clearly recognised. In addition, the SF agglomerates formed in the slurry were also detected. On the other hand, the chemical composition, status, and morphology of both SF and SF agglomerates in the 6-month-old paste were also identified. The study reported in this paper indicates that Raman spectroscopy could be a potential technique for tracing the status of SF, so that the potential safety hazards of SF can be monitored.

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Section: Characterisation Of a 6-month Sf Blended Paste With Raman Spsupporting

confidence: 52%

Application of Raman Spectroscopy for Tracing the Status of Silica Fume in Cementitious Materials

Yue¹,

Bai²,

Wang³

2016

Proceedings of the 5th International Conference on the Durability of Concrete Structures

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“…Commercial suppliers have responded by processing silica fume using different methods of densification and compaction in order to improve the handling and transport properties of material, such as densified, slurried or pelletized to increase its bulk density [4]. Many researchers pointed out that there is high degree of agglomeration of silica fume in concrete [4][5][6]18]. One typical SEM image of silica fume agglomeration was presented by Mitchell [6].…”

Section: Effect Of Silica Fume Particle Sizementioning

confidence: 99%

“…Silica fume has been used increasingly in the world to produce high performance concrete as it has been reported to improve the properties of concrete due to its high pozzolanic reactivity [ 1,2]. However some researchers found the different reactivity of silica fume [3][4][5][6] and even negative effect of silica fume on microstructure and properties of concrete [7,8]. Silica fume is a by-product of the manufacture of silicon or of various silicon alloys which are produced in so-called "submergedarc electric furnaces" [9].…”

Section: Introductionmentioning

confidence: 99%

Simulation of silica fume blended cement hydration

Cahyadi

2004

Mat. Struct.

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A model is proposed in this paper to simulate silica fume (SF) blended cement hydration based on the kinetics, stoichiometry and physical chemistry of cement hydration and pozzolanic reaction. The pozzolanic reaction degree, volume fraction of hydration products, capillary porosity and gel porosity can be obtained from model simulation. By using proper amount of silica fume replacement, the microstructure of silica fume blended cement paste is improved since the volume fraction of C-S-H gel is increased, Ca(OH)2 content and capillary porosity are decreased due to pozzolanic reaction compared with ordinary Portland cement (OPC) paste. The effects of silica fume particle size, glass phase content and the percentage of silica fume replacement on pozzolanic reaction degree, volume fraction of hydration products, and capillary porosity are simulated. The simulation results show that finer silica fume particles with higher glass phase content (GP) are of higher reactivity. There is an optimum silica fume replacement; extra silica fume only acts as inert filler because there is no enough Ca(OH)2 from cement hydration to react with it pozzolanically. RI~SUMI~

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“…O uso de cinzas volantes, de sílica ativa, metacaulim e de outros materiais pozolânicos permite reduzir substancialmente o consumo de cimento Portland (Mitchell et al, 1998;Payá et al, 2001;Isaia et al, 2003;Mishra et al, 2003;Frías & Rojas, 2005). Desta forma, a utilização de resíduos adequados em uma matriz cimentícia pode contribuir para que a indústria de materiais cimentícios se torne mais sustentável (Dwivedi et al, 2006).…”

Section: Introductionunclassified

Cinza de palha de cana-de-açúcar como adição mineral em fibrocimento

Rodrigues

Beraldo

Júnior

et al. 2013

Rev. bras. eng. agríc. ambient.

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RESUMOO Brasil é o maior produtor mundial de cana-de-açúcar e sua indústria sucroalcooleira gera grande quantidade de resíduos líquidos e sólidos, dentre eles a palha da cana-de-açúcar. Com o objetivo de agregar valor a este resíduo produziu-se, neste trabalho, cinza de palha de cana-de-açúcar por meio da queima controlada a 700 °C e se avaliou sua aplicação como adição mineral em compósitos de fibrocimento. A cinza foi caracterizada pelas técnicas de fluorescência de raios X, difração de raios X, granulometria a laser e superfície específica. Nos compósitos foram avaliadas as propriedades de absorção de água, porosidade aparente, massa específica aparente, módulo de ruptura, energia específica, módulo de elasticidade e limite de proporcionalidade. A caracterização das cinzas indicou superfície específica e porosidade elevadas, além de apresentar um halo de amorficidade no seu difratograma. Compósitos produzidos com as cinzas mostraram características físicas e mecânicas similares àquelas do controle o que viabiliza a substituição parcial do cimento Portland por esse tipo de cinzas. Palavras-chave: pozolana, resíduos agroindustriais, porosidadeSugarcane straw ash as mineral addition in fiber-cement ABSTRACT Brazil is the world's largest producer of sugarcane, and its sugarcane industry generates a large amount of liquid and solid wastes, among them the sugarcane straw. Aiming to add value to this waste, sugarcane straw ash was produced by controlled burning at 700 °C and it was applied as mineral addition in cement composites. The ashes were characterized by the techniques of X ray fluorescence, X ray diffraction, laser particle size and specific surface area. The following composite properties were evaluated: water absorption, apparent porosity, bulk density, modulus of rupture, specific energy, elastic modulus and proportionality limit. The characterization of ash showed a high specific surface area and porosity and a halo of amorphicity was observed in the diffractograms. Composites produced with these ashes showed physical and mechanical characteristics similar to that of the control, allowing the partial replacement of Portland cement by this type of ashes.

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Interaction of silica fume with calcium hydroxide solutions and hydrated cement pastes

Cited by 115 publications

References 8 publications

Application of Raman Spectroscopy for Tracing the Status of Silica Fume in Cementitious Materials

Application of Raman Spectroscopy for Tracing the Status of Silica Fume in Cementitious Materials

Simulation of silica fume blended cement hydration

Cinza de palha de cana-de-açúcar como adição mineral em fibrocimento

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