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Rahier, Hubert; Simons, Wim; Mele, Bruno Van; Biesemans, Monique

doi:10.1023/a:1018563914630

Cited by 189 publications

(51 citation statements)

References 1 publication

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“…The magnitude of temperature gradient that is required for 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 cracking to occur in cement paste was found to be between 20°C and 30°C over a 50 mm length. The severity of thermal incompatibility that geopolymer mortars suffered in the current investigation is higher than the ones reported [28] for Portland cement pastes because: (1) the measured temperature difference between center and outside of the geopolymer mortar was about 100°C when the temperature of furnace reached 800°C; (2) geopolymer and Portand cement paste exhibit comparable shrinkage at elevated temperature [23,29]; (3) geopolymer mortar contains sand in the paste matrix. Therefore, the level of thermal incompatibility experienced by the specimens in the current investigation is significant.…”

Section: Discussioncontrasting

confidence: 62%

An investigation of the mechanisms for strength gain or loss of geopolymer mortar after exposure to elevated temperature

2009

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Abstract:When fly ash based geopolymer mortars were exposed to a temperature of 800 o C, it was found that the strength after the exposure sometimes decreased, but at other times increased. This paper shows that ductility of the mortars has a major correlation to this strength gain/loss behaviour. Specimens prepared with two different fly ashes, with strengths ranging from 5 to 60 MPa, were investigated. Results indicate that the strength losses decrease with increasing ductility, with even strength gains at high levels of ductility. This correlation is attributed to the fact that mortars with high ductility have high capacity to accommodate thermal incompatibilities. It is believed that the two opposing processes occur in mortars: (1) further geopolymerisation and/or sintering at elevated temperatures leading to strength gain; (2) the damage to the mortar because of thermal incompatibility arising from non-uniform temperature distribution. The strength gain or loss occurs depending on the dominant process.

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Section: Discussioncontrasting

confidence: 62%

An investigation of the mechanisms for strength gain or loss of geopolymer mortar after exposure to elevated temperature

2009

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“…Alkali hydroxides are usually combined with an aluminosilicate source in the form of an aqueous solution (Provis, 2009). Given the complexity of the gel structure, which is formed through silicate activation of fly ash or metakaolin, and in particular its dependence on a large number of compositional and processing parameters, various approaches to the analysis of the gel binder were developed and implemented in the past years (Rahier et al, 1997, Palomo et al, 2005, Yao et al, 2009.…”

Section: Introductionmentioning

confidence: 99%

Influence of the carbonate-free clay calcination temperature and curing conditions on the properties of alkali-activated mortar

Būmanis

Bajāre

Korjakins

2014

Proceedings of the International Conference „Innovative Materials, Structures and Technologies”

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Abstract. Alkali-activated materials (AAMs) are one of the most perspective alternatives to the traditional Portland cement based materials. AAMs could reduce the environmental pollution and greenhouse gas emission due to the lower heat consumption in production (up to 80% compared to the ordinary Portland cement). In the current research alkaliactivated mortar was developed from the locally available low-carbonate Illite clay. Experimental work consisted of Illite clay calcination at different temperatures and regimes (from 500-800°C) and incorporation of the obtained material into the mixture of alkali-activated mortar. Four curing regimes were applied to alkali-activated mortar. The results indicate that hardened mortar properties are mainly affected by curing temperature and regime and the compressive strength up to 28.8MPa could be achieved for the mortar samples aged 2 months.

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“…The defining characteristic of a geopolymer is that the binding phase comprises an alkali aluminosilicate gel, with aluminium and silicon linked in a three-dimensional tetrahedral gel framework that is relatively resistant to dissolution in water [16,17,8]. Research has shown that geopolymers may be readily synthesised through alkali-activation of inexpensive and pure starting materials such as kaolinitic clays [19,20,21], as well as waste products such as fly ash and furnace slag [18,22,23,24,25].…”

Section: Introductionmentioning

confidence: 99%

The Potential of Laterite Soils Deposit South Sulawesi as a Precursor for Na-Poly (Ferro-Sialate) Geopolymers

2017

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Abstract.The main objectives of this study was to investigate the potential of lateritic soils deposit South Sulawesi, Indonesia as a precursor for Na-poly(ferro-sialate) geopolymers. The samples of laterite soils were taken from three different regions, namely Sidrap, Bone, and Gowa regency. The soil was clean, grounded, sieves 200 mesh, and dehydroxylated at 750 o C for 2 hours. The x-ray fluorescence (XRF) and energy dispersive spectroscopy (EDS) were used to examine the chemical compositions of the soils. The geopolymers was synthesized through alkali activation method by adjusting the molar oxide ratios of SiO 2 /(Al 2 O 3 +Fe 2 O 3 ), Na 2 O/SiO 2 and H 2 O/Na 2 O in accordance with the chemical compositions of the soils. The functional groups of the resulting geopolymers were examined by using Fourier Transform Infra-Red (FTIR). The structure and phase of the resulting material were studied by using x-ray diffraction (XRD). The surface morphology of geopolymers was studied by using scanning electron microscopy (SEM). The mechanical strength of the materials was examined through compressive strength measurement. The results of this study showed that high strength Na-poly (ferro-sialate) geopolymers were successfully produced and characterized.

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Cited by 189 publications

References 1 publication

An investigation of the mechanisms for strength gain or loss of geopolymer mortar after exposure to elevated temperature

An investigation of the mechanisms for strength gain or loss of geopolymer mortar after exposure to elevated temperature

Influence of the carbonate-free clay calcination temperature and curing conditions on the properties of alkali-activated mortar

The Potential of Laterite Soils Deposit South Sulawesi as a Precursor for Na-Poly (Ferro-Sialate) Geopolymers

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