Properties of Alkali Activated Aluminosilicate Material after Thermal Load

Zuda, Lucie; Pavlík, Zbyšek; Rovnanı́ková, Pavla; Bayer, Patrik; Černý, Robert

doi:10.1007/s10765-006-0077-7

Cited by 75 publications

(36 citation statements)

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“…Other studies have concentrated on the thermal mechanical properties of AAS mortars [24][25][26][27] (activated by sodium silicate, sodium hydroxide and combination of these activators). Recent work has also been published regarding the thermal material properties of sodium silicate-activated AAS mortars [28].…”

Section: Introductionmentioning

confidence: 99%

“…Investigations on the fire performance of dried sodium silicate AAS mortars up to 1200 • C [24][25][26] using electrical porcelain [25,26] and quartz aggregate [25][26][27] as aggregates concluded that the remaining strength in the order of 20% at 800 • C is a result of the dehydration process in the matrix as explained previously [24]. Between 800 and 1200 • C, the strength increased in the quartz AAS mortar (87% of it original strength), which was explained by the formation of a new crystalline phase, akermanite, which provided strength increase due to a sintering between binder and aggregate [26].…”

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Residual compressive behavior of alkali‐activated concrete exposed to elevated temperatures

2008

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SUMMARYThis paper reports the effect of elevated temperature exposures, up to 1200 • C, on the residual compressive strengths of alkali-activated slag concrete (AASC) activated by sodium silicate and hydrated lime; such temperatures can occur in a fire. The strength performance of AASC in the temperature range of 400-800 • C was similar to ordinary Portland cement concrete and blended slag cement concrete, despite the finding that the AASC did not contain Ca(OH) 2 , which contributes to the strength deterioration at elevated temperatures for Ordinary Portland Cement and blended slag cement concretes. Dilatometry studies showed that the alkali-activated slag (AAS) paste had significantly higher thermal shrinkage than the other pastes while the basalt aggregate gradually expanded. This led to a higher thermal incompatibility between the AAS paste and aggregate compared with the other concretes. This is likely to be the governing factor behind the strength loss of AASC at elevated temperatures.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Residual compressive behavior of alkali‐activated concrete exposed to elevated temperatures

2008

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“…Soluble silicate is an essential factor of geopolymerization process, as it provides the aqueous phase of the geopolymeric system with soluble silicate species, which are necessary for the initiation of oligomers formation and thus the polycondensation process (16,(36)(37)(38)(39).At each curing temperature, an increase in the initial SiO 2 concentration in the aqueous phase under constant NaOH concentration resulted in an increase in the SiO 2 /Na 2 O mass ratio at the early stages of the geopolymerization process, therefore speeding up the setting process. As can also be seen in Figure 8, the setting time of the perlite geopolymer pastes converged towards the same value as the SiO 2 concentration in the aqueous phase increased, independently of the curing temperature.…”

Section: Effect Of Initial Sio 2 Contentmentioning

confidence: 99%

Characterization of the properties of perlite geopolymer pastes

2016

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This paper deals with the characterization of perlite-based geopolymer pastes, using fine perlite as raw material. The present study examined the effects of the main synthesis parameters such as perlite to activator ratio, NaOH concentration, the addition of soluble silica to the activator, and curing temperature on the setting time, the stability in an aquatic environment, the viscosity of the paste, and the compressive strength of the solidified geopolymers. The results showed that these inorganic polymer pastes are non-Newtonian shear thinning fluids that achieve low viscosities at high shear stresses. The optimum synthesis conditions for the geopolymer pastes proved to be a) a low initial NaOH concentration in the alkaline phase (2-5 M) and b) a solid to liquid ratio of 1.2-1.4 g/mL. If very fast setting is necessary, the pastes should be prepared with a soluble silica-doped alkaline activating phase and cured at high temperatures around 90 °C. RESUMEN: Caracterización de las propiedades de pastas geopoliméricas de perlita.El presente trabajo trata de la caracterización de pastas geopoliméricas basadas en perlita utilizando perlita fina como materia prima. Se han examinado los efectos que tienen los principales parámetros de síntesis -tales como la relación perlita/activador, la concentración de NaOH, la adición de sílice soluble al activador y la temperatura de curado-sobre el tiempo de fraguado, la estabilidad en medio acuoso, la viscosidad de la pasta y la resistencia a la compresión de los geopolímeros solidificados. Los resultados han mostrado que estas pastas poliméricas inorgánicas son fluidos no-Newtonianos de viscosidad estructural que alcanzan bajos niveles de viscosidad a alta tensiones de cizalla. Las condiciones óptimas de síntesis para las pastas geopoliméricas resultaron ser a) baja concentración inicial de NaOH en la fase alcalina (2-5 M) y b) una relación sólido-líquido entre 1,2 y 1,4 g/mL. Si se requiere fraguado muy rápido, se tienen que preparar las pastas con un activador alcalino dopado con sílice soluble y curar a altas temperaturas cercanas a los 90 °C.

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“…Studies show that the thermal stability of alkali-activated binding materials is higher than that of common Portland cement. Some experimental results have shown that the compressive strength of the former even improves after heating due to the sintering reaction or polymerization reaction happening under high temperature (Xu, Li, Shen, Wang, & Zhai, 2010;Zuda, Pavlik, Rovnanikova, Bayer, & Cerny, 2006). In addition, the porosity of alkali-activated slag concrete is commonly low due to the dense matrix and the optimized interfacial transition zone, and so the thermal conductivity is better than that of common concrete, which is good for thermal storage utilization (Kong, Zhang, Ni, Jiang, & Fang, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the porosity of alkali-activated slag concrete is commonly low due to the dense matrix and the optimized interfacial transition zone, and so the thermal conductivity is better than that of common concrete, which is good for thermal storage utilization (Kong, Zhang, Ni, Jiang, & Fang, 2009). Zuda et al (2006) investigated the performances of alkali-activated slag binding material under different thermal loadings, and it was found that the materials had good heat resistance ability, the thermal conductivity can be as high as 1.67 W m-1 K-1, and a suitable aggregate was beneficial for improving the thermal conductivity further. Laing et al (2012) utilized slag cement, sand, and gravel to prepare thermal storage concrete that can be used in 500 °C environments.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Properties of Alkali-Activated Ground-Granulated Blast Furnace Slag Thermal Storage Concrete

Lü¹,

Ping²,

He³

et al. 2014

Proceedings of the 4th International Conference on the Durability of Concrete Structures

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Thermal storage concrete is prepared by using alkali-activated ground-granulated blast furnace slag as cementitious material. To improve thermal conductivity, graphite aggregate is used to replace part of the coarse aggregate, and, furthermore, polypropylene fiber is added to improve the heat resistance performance of the concrete. The compressive strength of concrete specimens before and after heating (up to 450 °C) was tested, and, furthermore, scanning electron microscopy was used to investigate the structure alteration due to heating. Results showed that the partial replacement of coarse aggregate by graphite block could obviously improve the thermal conductivity of the thermal storage concrete. At the same time, the specimen with 30% graphite aggregate replacement still exhibited good mechanical properties. The mechanism of the high residual strength was investigated.

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Properties of Alkali Activated Aluminosilicate Material after Thermal Load

Cited by 75 publications

References 5 publications

Residual compressive behavior of alkali‐activated concrete exposed to elevated temperatures

Residual compressive behavior of alkali‐activated concrete exposed to elevated temperatures

Characterization of the properties of perlite geopolymer pastes

Preparation and Properties of Alkali-Activated Ground-Granulated Blast Furnace Slag Thermal Storage Concrete

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