The effect of deflocculants on the self-flow characteristics of ultra low-cement castables in Al2O3–SiC–C system

Otroj, Sasan; Bahrevar, M.A.; Mostarzadeh, Fatollah; Nilforoshan, Mohammad Reza

doi:10.1016/j.ceramint.2004.06.023

Cited by 32 publications

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“…In a cement slurry with MK S it is necessary to add 0.25% deflocculant in order to achieve a viscosity of 2500 MPa · sec, and with the maximum amount of deflocculant (1%) the slurry viscosity with low-quality MS is 840 MPa · sec, and this makes it readily possible to compact it. In order to obtain a self-flowing composition for some systems the slurry viscosity should not exceed 375 MPa · sec [16]. This study confirms the particular role of the effect of MS quality on the rheological properties of cement slurry and the possibility of controlling viscosity with use of deflocculant Castament FS 20.…”

Section: Study Of the Possible Application Of Low Quality Microsilicasupporting

confidence: 76%

Study of the possible application of low quality microsilica in medium cement heat-resistant concrete with deflocculant Castament FS 20

et al. 2007

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Results are presented for a study of the features of pH and electrical conductivity (EC) in suspensions of microsilica (MS) of different quality. The effect of the amount of deflocculant Castament FS 20 on changes in pH and EC of these suspensions and on viscosity of the MS slurry is determined. The effect of type of MS on changes in pH and EC in cement-microsilica suspensions and on the viscosity of cement-microsilica slurries is established. The possibility is demonstrated with addition of deflocculant Castament FS 20 to use MS of lower quality in medium-cement heat-resistant concrete providing satisfactory characteristics for it.Numerous publications concerning the new generation of heat-resistant concretes devote considerable attention to microsilica (MS) quality on the engineering and thermomechanical properties of concrete. It has been established that impurities in MS may cause undesirable aftereffects leading to a sharp change in concrete rheological properties. Therefore the manufacturers strive to prepare heat-resistant concrete using high quality MS with the minimum impurity content, although it is more expensive by a factor of six to eight than low-quality MS. Researchers of the firm Lafarge [1] confirm that the presence of impurities Na 2 O, K 2 O, MgO, and SO 3 in MS have a capacity to form a gel and particle flocculation, reducing the spreading capacity of the concrete slurry. A high carbon content in MS impurities slows down formation of crystal hydrates during cement hydration, which leads to a reduction in strength in compression. Presence of SO 3 slows down hydration and prolongs concrete hardening period. An increase in pH in the system with dissolution of impurities sometimes excessively accelerates cement hydration and reduces the viability of the concrete slurry.It is very difficult in practice to consider each of these factors since it is not always possible to carry out chemical analysis of each individual batch of MS, and variations in MS properties and quality for different batches is known to the producers themselves [2,3]. Studies have shown [4,5] that MS even of quite close chemical composition have a different pH, and impurities existing within them may markedly affect the spreading capacity of the concrete slurry.In order to use MS in heat-resistant concrete with a high impurity content it is necessary to find deflocculants. It has been shown in [6] in order to plan good mobility of low-cement concrete at 5°C it is necessary to vary the amount of components in the system of sodium triphosphate (0.005 -0.2%), MS (4 -6%) and cement (4 -6%) in relation to MS quality.The aim of this work is to study the effect of a deflocculant on the rheological properties and pH and EC parameters for a binder system with MS of different quality, and to determine the possibility of using low-quality MS within the composition of medium-cement heat-resistant concrete without worsening its characteristics. EXPERIMENTAL PARTThe following materials were used in tests: MS grade 983U (condition E) from the N...

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Section: Study Of the Possible Application Of Low Quality Microsilicasupporting

confidence: 76%

Study of the possible application of low quality microsilica in medium cement heat-resistant concrete with deflocculant Castament FS 20

et al. 2007

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“…All the samples had excellent resistance to slag penetration and melting loss. .. (3) .. (4) .. (5) .. (6) ..(7) However, the erosion reaction was serious on the three phase border among matrix, slag and air, in which the apertures of the crucibles were enlarged. Moreover, in the interior structures of the diameters in these samples, it was difficult to determine which one was expanded greater than others as well as their outlines among them.…”

Section: Corrosion Resistance Of Al 2 O 3 -Sic-c Refractory Castablesmentioning

confidence: 97%

“…1 Especially, Al 2 O 3 -SiC-C refractory castables are primarily used in main blast furnace troughs due to their superior properties, such as superior corrosion resistance, oxidation resistance and thermal shock resistance in the environment with liquid slags. 2,3 In order to improve high temperature resistance of refractory castables and to reduce deformation, oxidation and corrosion, the liquid content formed at high temperatures on Al 2 O 3 -SiC-C refractory castables is reduced as far as possible. 4 In cement refractory castables, the reaction among alumina, SiO 2 and CaO commonly occurs because the low melting point eutectic phases, which have crucial negative influence on the performance of refractory castables at elevated temperatures, are often formed from aluminium silicate cement.…”

Section: Introductionmentioning

confidence: 99%

Influence of β-Sialon/Ti(C, N) Powders on the Corrosion and Oxidation Resistance of Zero-Cement Al₂O₃-SiC-C Refractory Castables

Yang

Liu

Ding

et al. 2015

Transactions of the Indian Ceramic Society

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Al 2 O 3 -SiC-C refractory castables added with -sialon/Ti(C, N) powders were prepared with silica sol and phenolic resin as binding agents at room temperature. The effects of -sialon/Ti(C, N) powders, silica sol and phenolic resin on slag penetration and corrosion resistance as well as oxidation resistance of the refractory castables were investigated by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscope. Corrosion resistance and oxidation resistance mechanisms of the Al 2 O 3 -SiC-C refractory castables were also discussed. The results showed that the castables obtained with silica sol as the binding agent at a temperature of 1450 o C presented better oxidation resistance. The oxidation resistance and slag erosion resistance of the refractory castables could be improved by adding Ti(C, N)/-sialon powders. Static crucible method and fractal dimension calculation result showed that the prepared castables possessed excellent slag erosion resistance.

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“…In view of this it is quite interesting to use in heat-resistant concrete composite (mixed) deflocculants, that expand the possibility of controlling hydration and material structure, and thereby making it possible to improve the physicomechanical and other properties of concrete. Studies by S. Otroj [7] have shown that due a mixed deflocculant (sodium triplyphosphate and polycarboxylate ester) it was possible to increase the ultimate strength in compression of self-spreading heat-resistant concrete with spinel fillers from 30 to 40 MPa after drying at 110°C, and from 90 to 170 MPa after firing at 1500°C.…”

Section: Introductionmentioning

confidence: 97%

Effect of composite deflocculant on the properties of medium-cement heat-resistant concrete

Pundene¹,

Antonovich²,

Stonis³

2009

Refract Ind Ceram

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Comparative analysis is provided for the properties of medium-cement concrete based on mullite filler in relation to different type of deflocculant. The effect of different deflocculants on concrete structure formation, hydration, rheology, strength and heat resistance is discussed. It is proposed that in concrete with a composite deflocculant it is possible to form nano-structures as a result of which there is a considerable increase in concrete strength after drying at 110°C.

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The effect of deflocculants on the self-flow characteristics of ultra low-cement castables in Al2O3–SiC–C system

Cited by 32 publications

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Study of the possible application of low quality microsilica in medium cement heat-resistant concrete with deflocculant Castament FS 20

Study of the possible application of low quality microsilica in medium cement heat-resistant concrete with deflocculant Castament FS 20

Influence of β-Sialon/Ti(C, N) Powders on the Corrosion and Oxidation Resistance of Zero-Cement Al₂O₃-SiC-C Refractory Castables

Effect of composite deflocculant on the properties of medium-cement heat-resistant concrete

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The effect of deflocculants on the self-flow characteristics of ultra low-cement castables in Al2O3–SiC–C system

Cited by 32 publications

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Study of the possible application of low quality microsilica in medium cement heat-resistant concrete with deflocculant Castament FS 20

Study of the possible application of low quality microsilica in medium cement heat-resistant concrete with deflocculant Castament FS 20

Influence of β-Sialon/Ti(C, N) Powders on the Corrosion and Oxidation Resistance of Zero-Cement Al2O3-SiC-C Refractory Castables

Effect of composite deflocculant on the properties of medium-cement heat-resistant concrete

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Influence of β-Sialon/Ti(C, N) Powders on the Corrosion and Oxidation Resistance of Zero-Cement Al₂O₃-SiC-C Refractory Castables