Accelerating effects of colloidal nano-silica for beneficial calcium–silicate–hydrate formation in cement

Björnström, Joakim; Martinelli, Anna; Matic, Aleksandar; Börjesson, Lars; Panas, Itai

doi:10.1016/j.cplett.2004.05.071

Cited by 557 publications

(269 citation statements)

References 22 publications

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“…Only, there are several reports on incorporation of nanoparticles in NVCs which most of them have focused on using SiO 2 nanoparticles [10][11][12][13][14][15][16][17][18][19] and TiO 2 nanoparticles 20,21 .…”

Section: Introductionmentioning

confidence: 99%

The effects of ZrO2 nanoparticles on physical and mechanical properties of high strength self compacting concrete

Nazari

Riahi

2010

Mat. Res.

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In this work, strength assessments and coefficient of water absorption of high performance self compacting concrete containing different amounts of ZrO 2 nanoparticles have been investigated. The results indicate that the strength and the resistance to water permeability of the specimens are improved by adding ZrO 2 nanoparticles in the cement paste up to 4.0 wt. (%). ZrO 2 nanoparticles, as a result of increased crystalline Ca(OH) 2 amount especially at the early age of hydration, could accelerate C-S-H gel formation and hence increase the strength of the concrete specimens. In addition, ZrO 2 nanoparticles are able to act as nanofillers and recover the pore structure of the specimens by decreasing harmful pores. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that ZrO 2 nanoparticles could improve mechanical and physical properties of the concrete specimens.

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Section: Introductionmentioning

confidence: 99%

The effects of ZrO2 nanoparticles on physical and mechanical properties of high strength self compacting concrete

Nazari

Riahi

2010

Mat. Res.

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“…Como resultado, uma maior densificação da matriz de cimento será obtida e, por conseguinte, uma maior resistência e durabilidade de pastas, argamassas ou concretos. Vários autores [3][4][5][6][7][8][9][10][11][12][13] estudaram a influência da nano-SiO 2 em propriedades como resistência a compressão ou flexão, índice de consistência, calor de hidratação, tempo de pega, além da microestrutura. Entretanto, não houve indicação do uso da reologia nos trabalhos consultados.…”

Section: Introduçâounclassified

Comportamento reológico de pastas de cimento com adição de sílica ativa, nanossílica e dispersante policarboxílico

2010

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RESUMONeste trabalho é apresentado um estudo sobre o efeito da adição da sílica ativa (SA), nanossílica (NS) e aditivo dispersante policarboxílico (SP) sobre o comportamento reológico de pastas de cimento (CP V ARI RS). Para fins comparativos com a pasta de referência (REF), foram produzidas pastas com SA, em diferentes teores em massa (0 a 10%) e pastas com 1,0% de NS. Em todas as pastas estudadas (REF, SA e NS) variou-se SP entre 0 a 0,5%, relativos à massa de cimento. Os ensaios foram realizados em um reômetro com geometria de cilindros concêntricos e taxa máxima de cisalhamento aplicada de 100 s -1 . Os aumentos de SP causaram a redução na área de histerese, na viscosidade plástica e na tensão de escoamento, sendo esta última mais influenciada que a viscosidade plástica. Nas pastas cujos resultados foram ajustados por Bingham, as misturas contendo um mesmo teor SP, a tensão de escoamento de Bingham não variou substancialmente, exceto nas pastas com 10% de SA e 0.1 a 0.3% de SP. Para a viscosidade plástica não foi observada tal tendência. Entretanto, NS influenciou significativamente o valor da viscosidade plástica em relação à REF e à SA. Nas pastas cujos resultados apresentaram aproximação satisfatória quando ajustados ao modelo de Bingham e Herschel-Bulkley, para uma mesma dosagem de SA, os aumentos nos teores de SP causaram redução na tensão de escoamento e na viscosidade plástica. O modelo de Bingham descreve adequadamente o comportamento reológico das misturas com a tensão de cisalhamento com valores intermediários, enquanto que o modelo de Herschel-Bulkley é mais adequado para as tensões máxima de cisalhamento elevadas ou reduzidas.Palavras-chaves: silica ativa, nanossílica, pasta de cimento. Rhelogycal behaviour of cement pastes with addition of silica fume, nanosilica and polycarboxilic dispersant ABSTRACTThis article shows the results of an investigation about the effect of silica fume (SF), nanosilica (NS) and superplasticizer (SP) addition on the rheological behavior of CP V ARI RS cement pastes. Cement pastes with different content of SF (0 to 10 wt%) and 1.0 wt% NS were compared to REF (without mineral addition). For all samples studied (REF, NS and SF), SP ranged 0 to 0.5 wt% relative to cement. A rheometer with concentric cylinders geometry was used and the maximum shear rate of 100 s -1 was applied. When SP is added into the mixtures, the hysteresis area, plastic viscosity and yield stress decreased. The latest was more affected than plastic viscosity. When SF was added, the yield stress did not change significantly, except in samples with 10 % SF and SP between 0.1 to 0.3 wt%. In relation to plastic viscosity, the difference was not visualized. However, NS influences more the plastic viscosity than REF and SF. The Bingham model describes properly the rheological behavior of mixtures at intermediate values of shear stress, while the Herschel-Bulkley model are more adequate at high and low values of shear stress.

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“…The broad band detected at 3711 cm -1 in the infrared spectroscopy of OPC linked to overlap stretching vibrations of both the structural and free hydroxy groups of CH and water respectively. FTIR spectra of RC, CA, FA20CA which have been defined as fingerprint evidence for the degree of polymerization with the formation of calcium-silicate-hydroxide phase due to hydration [24] having strong band observed at 900 cm -1 and the band observed at 520 cm -1 were associated with the bending-in-plane vibrations of the Si-O bonds in C3S (tricalcium silicates) and C2S (dicalcium silicates) [25][26][27][28]. The intensity of these bending-in-plane vibrations of the Si-O bonds decreased as calcium-silicate-hydroxide crystals formed [24,29].…”

Section: Microstructural Analysismentioning

confidence: 99%

Self-Healing Ability of High-Strength Fibre-Reinforced Concrete with Fly Ash and Crystalline Admixture

Reddy

Theja²,

Sashidhar

2018

CivileJournal

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The aim of this study is to analyse the self-healing capability of high-strength fibre-reinforced concrete (M70) with fly ash and crystalline admixture (CA) in four types of environmental exposures i.e. Water Immersion (WI), Wet-Dry Cycles (WD), Water contact (WC) and Air Exposure (AE). Specimens for four mixes are cast, one mix containing 1.1% of CA and three mixes with 10%, 20% and 30% partial replacement of cement with fly ash and additions of 1.1% CA. The specimens were pre-cracked at 28 days, in the range of 0.10-0.40 mm and the time set for healing was 42 days. The result shows that all the mixes have considerable amount of closing ability and strength-regaining capability for all exposure conditions. The concrete with 20% fly ash and 1.1% CA has complete crack closing ability and 100% strength-regaining capability for WI and WD cycle conditions. From SEM analysis, it is confirmed that self-healing products are CaCO3 and C-S-H gel.

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Accelerating effects of colloidal nano-silica for beneficial calcium–silicate–hydrate formation in cement

Cited by 557 publications

References 22 publications

The effects of ZrO2 nanoparticles on physical and mechanical properties of high strength self compacting concrete

The effects of ZrO2 nanoparticles on physical and mechanical properties of high strength self compacting concrete

Comportamento reológico de pastas de cimento com adição de sílica ativa, nanossílica e dispersante policarboxílico

Self-Healing Ability of High-Strength Fibre-Reinforced Concrete with Fly Ash and Crystalline Admixture

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