Reactivity of blast-furnace slag in Portland cement blends hydrated under different conditions

Escalante, J. I.; Gómez, L. Martónez; Johal, Kuldip; Mendoza, G.; Mancha, H.; Méndez, José Alberto

doi:10.1016/s0008-8846(01)00587-7

Cited by 281 publications

(112 citation statements)

References 10 publications

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“…They also found that as the w/b ratio decreased or the slag ratio increased, the hydration degree decreased, and the slag type also influenced the reactivity. Escalante et al (2001) also reported that the reactivity of slag decreased with the w/b ratio or with increases of the slag ratio. They pointed out also that the hydration degree increases with the temperature, and the values after 6 months were 20-50% in the range of 10-30℃.…”

Section: Introductionmentioning

confidence: 92%

“…The tests adopted in Table 1 are all under the reference temperature (293 K). If the curing temperature increases, a higher hydration degree of slag will be obtained (Escalante et al 2001). In the original model, this effect is included in Eq.…”

Section: Verification By Hydration Degree Of Slag and Ch Contentmentioning

confidence: 99%

“…However, because it is difficult to separate the heat released by slag accurately, this method is not capable of evaluating the reaction of the slag separately. On the other hand, several test methods have been developed for quantitatively analyzing the hydration degree of slag separately, such as selective dissolution (Kondo and Ohsawa 1969;Luke and Glasser 1987;Lumley et al 1996;Demoulian et al 1980;Battagin 1992;Escalante et al 2001), XRD (Kondo et al 1975;Hoshino et al 2006), Differential Scanning Calorimetry (DSC) (Totani et al 1980;Imoto et al 2006) and image analysis (Feng et al 2004;Kurumisawa et al 2007). Thanks to advances in techniques, test methods are becoming more accurate and reveal the hydration process and reactivity of slag.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

Luan

Ishida

Nawa

et al. 2012

ACT

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Analytical hydration model for filler rich self-compacting concrete AbstractA hydration model for cementitious materials was applied to slag blended cement. The original model was found to overestimate the hydration degree of slag, and the influence of the slag ratio on the hydration degree not to be well simulated either. The hydration mechanism of slag was investigated, considering the role of calcium hydroxide as activator and the Ca/Si ratio of C-S-H. It is assumed that for low Ca/Si ratio, the C-S-H inner product has a stronger resistance against ion diffusion and thus influences the hydration process significantly. Accordingly an enhanced model for slag hydration is proposed. Finally, the enhanced model is verified by both hydration degree and heat generation tests.

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Section: Introductionmentioning

confidence: 92%

Section: Verification By Hydration Degree Of Slag and Ch Contentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

Luan

Ishida

Nawa

et al. 2012

ACT

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“…Sin embargo, una rápida hidratación inicial puede generar una microestructura menos homogénea con un elevado porcentaje de poros y una disminución de la hidratación a edades más avanzadas [5] debido a que la acumulación de los productos de hidratación sobre los granos de cemento anhidro retrasa su hidratación posterior [16], generando una menor ganancia de la resistencia de la pasta de cemento a edades avanzadas (ver Figuras 3c y d, 4c y d).…”

Section: Difracción De Rayos Xunclassified

“…En este sentido, Escalante et al [5,6] han determinado que la reactividad y la resistencia de las pastas con escoria se incrementa con la temperatura de curado. En pastas de cemento con escoria (30 %) hidratadas a temperaturas de 10, 30 y 50 ºC, han observado que al cabo de los 28 días la cantidad de escoria reaccionada es de 30, 35 y 42 %, respectivamente.…”

Section: Introductionunclassified

Influencia de la temperatura de curado: hidratación y resistencia de pastas de cemento con escoria

2010

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RESUMENActualmente son muy conocidos los beneficios tecnológicos, económicos y el menor impacto medioambiental que produce el empleo de adiciones minerales como reemplazo del cemento portland. Estas razones, han consolidado el uso de muchas adiciones como: escoria granulada de alto horno, ceniza volante, material calcáreo, humo de sílice, etc.En los últimos años, los cementos presentan un importante aumento en el contenido de las adiciones; el cual influye sobre la distribución de partículas, sobre la velocidad y naturaleza de las reacciones de hidratación y en consecuencia en su ganancia de resistencia.El presente trabajo evalúa la influencia de la temperatura en el curado (20, 40 y 60 ºC) de pastas con contenido variable de escoria granulada de alto horno (0 a 80 %) elaboradas con relación agua/material cementante de 0,40, sobre la resistencia mecánica. La evolución de la hidratación se estudió a través del análisis de los compuestos de hidratación por DRX y el contenido de agua no evaporable. La resistencia mecánica se evaluó empleando un diseño de experimentos central compuesto centrado.Los resultados obtenidos indican que a medida que la temperatura de curado aumenta con el incremento del contenido de escoria en el cemento mezcla, se aumentan la resistencia y el contenido de agua no evaporable, y disminuye la cantidad de hidróxido de calcio de la pasta.Palabras clave: Cemento portland, escoria granulada de alto horno, resistencia mecánica, DRX, agua no evaporable, activación térmica. Influence of curing temperature: hydration and strength of cement paste with granulated blast furnace ABSTRACTNowadays it is well known that using blast furnace slag as partial replacements for Portland cement adds technological, economic and environmental benefits. Those are some of the reasons why cements containing several additions (blast furnace slag, fly ash, calcareous material, etc) are commonly used.In recent years, blended cements started to increase amounts of additions as replacement of Portland cement; in this regard these variations influence the rate and the mechanism of hydration and, consequently, strength development.The present work evaluated the effect of different curing temperatures (20, 40 and 60 ºC) on the mechanical strength of cement paste with different proportions of granulated blast-furnace slag (0 to 80 %). Pastes were prepared with water/cementitious material ratio (w/cm) equal to 0,4.The hydration evolution was determinated following the hydration products using XRD analysis and evaluated the content of non evaporable water. Mechanical strength was evaluated trough central composite experimental design.When granulated blast-furnace slag content increases with curing temperature, the results show that mechanical strength and non evaporable water increases, while the calcium hydroxide content decreases.

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Mineralogy and glass content of Fe‐rich fayalite slag size fractions and their effect on alkali activation and leaching of heavy metals

Adediran

Yliniemi

Illikainen

2021

Int J Ceramic Engine & Sci

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Fayalite slag (FS) is an Fe-rich nonferrous metallurgy (CaO-MgO-) FeOx-SiO 2 slag originating from nickel or copper manufacturing processes, which currently is disposed to landfills or used in low-value applications. This study investigates the mineralogy and glass content of certain sized fractions of FS and how it influences the reactivity, mechanical, and microstructural properties of the alkaliactivated materials produced. Water-quenched granular FS was sieved into two size fractions: namely, a fine fraction (FF) with a particle size range of 0-0.5 mm and a coarse fraction (CF) with a particle size range of 1.5-2 mm. It was then milled to a similar median particle size of 10 μm to be used as a binder precursor. The reaction kinetics of each fraction was determined via thermal analysis microcalorimeter, and the microstructural evolution and chemical composition of the binder were studied using a scanning electron microscope coupled with an energy dispersive X-ray spectroscopy. The environmental leaching behavior of both fractions before and after alkali activation was assessed according to the EN 12457-2 standard. The results showed that both fractions consisted of fayalite, magnetite crystalline phases, and MgO-SiO 2 -FeOx (-CaO-Al 2 O 3 ) glass phase. However, FF had a higher glass content (63 wt.%) in comparison to CF (39 wt.%), and, consequently, FF was more reactive under alkali activation, as evidenced by faster reaction kinetics, faster strength development, and improved microstructural properties. Alkali-activated samples had differences in the chemical compositions of their binder gels at early stages, though later, their binders became increasingly homogenous and consisted of an Na-K-Fe-Si gel with Mg, Ca, and Al as minor constituents in both samples. Additionally, the leaching behavior of potentially toxic metals and substances from precursors and alkali-activated samples prepared was below the limits set for paved structures as specified by Finnish legislation.

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Reactivity of blast-furnace slag in Portland cement blends hydrated under different conditions

Cited by 281 publications

References 10 publications

Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

Influencia de la temperatura de curado: hidratación y resistencia de pastas de cemento con escoria

Mineralogy and glass content of Fe‐rich fayalite slag size fractions and their effect on alkali activation and leaching of heavy metals

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