Influence of curing schedule on the integrity of geopolymers

Perera, D. S.; Uchida, O.; Vance, E. R.; Finnie, Kim S.

doi:10.1007/s10853-006-0533-6

Cited by 187 publications

(106 citation statements)

References 12 publications

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“…Previous research comparing different Al:Si ratios has shown that a ratio of 2 results in relatively high strength geopolymers [24][25][26][27]. The water content of 8 moles per mole of Al gave adequate paste workability and good geopolymer strength development [28][29][30].…”

Section: Preparation Of Geopolymer Mortar Samplesmentioning

confidence: 99%

Production of nepheline/quartz ceramics from geopolymer mortars

Kuenzel

Grover

Vandeperre

et al. 2013

Journal of the European Ceramic Society

125

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This research has investigated the mechanical properties and microstructure of metakaolin derived geopolymer mortars containing 50% by weight of silica sand, after exposure to temperatures up to 1200 °C. The compressive strength, porosity and microstructure of the geopolymer mortar samples were not significantly affected by temperatures up to 800 °C.Nepheline (NaAlSiO 4 ) and carnegieite (NaAlSiO 4 ) form at 900 ºC in the geopolymer phase and after exposure to 1000 °C the mortar samples were transformed into polycrystalline nepheline/quartz ceramics with relatively high compressive strength (~275 MPa) and high Vickers hardness (~350 HV). Between 1000 and 1200 °C the samples soften with gas evolution causing the formation of closed porosity that reduced sample density and limited the mechanical properties.2

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Section: Preparation Of Geopolymer Mortar Samplesmentioning

confidence: 99%

Production of nepheline/quartz ceramics from geopolymer mortars

Kuenzel

Grover

Vandeperre

et al. 2013

Journal of the European Ceramic Society

125

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“…To achieve high performance, the precursor(s) must contain a sufficient amount of reactive glass, have a low water demand and be able to release aluminium easily [17]. Studies have been conducted on pure MK (paste [18][19][20], mortar [21] or concrete [22]). One of the main drawbacks of MK-geopolymer is a tendency to shrink and crack on drying [23,24].…”

Section: Introductionmentioning

confidence: 99%

Formulation and characterization of blended alkali-activated materials based on flash-calcined metakaolin, fly ash and GGBS

Samson

Cyr

Gao

2017

Construction and Building Materials

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Highlights AAMs initial setting time, shrinkage, mass loss, compressive strength were studied. Low activation leads to high drying shrinkage because of important mass loss. Very low shrinkage values were found for MK-GGBS compared to the other AAMs. High early strength compressive strength was observed for MK-GGBS blends. Graphical abstract 2 AbstractStudies performed on alkali-activated materials (AAMs) in recent years reveal that they could be an alternative to ordinary Portland cement (OPC). The main precursors used are flash-calcined metakaolin (MK), fly ash (FA), and ground granulated blast furnace slag (GGBS). Usually, only one precursor is used to produce an AAM. The aims of this study were to measure and compare the performances of pure (one precursor) and blended AAMs (two precursors). Alkaline solution is added to activate the precursors and the influence of the activation rate was also investigated by changing the activator amount (15% and 25% of alkaline solution dry extract). Twenty-six different mixes were studied and are presented in a ternary representation. The mixtures were characterized in the fresh state (initial setting time) and the main properties useful for building applications (shrinkage, mass loss, and compressive strength) were recorded and analysed. In contrast to the situation in OPC systems, shrinkage and mass loss in AAMs were not directly correlated. The high shrinkage values observed for pure MK AAMs and pure GGBS AAMs were significantly reduced when they were associated in appropriate proportions. The association of MK and GGBS also proved very interesting regarding early age compressive strength.Keywords: Alkali-activated material (AAM), metakaolin (MK), fly ash (FA), ground granulated blast furnace slag (GGBS), compressive strength, shrinkage 3 IntroductionThe building sector is faced with the gradual exhaustion of natural resources and/or increasing difficulty in accessing them. 27°C, the reaction of alkali-activated GGBS-FA blend paste is dominated by the GGBS activation (dissolution and precipitation of C-A-S-H) while at 60°C the reaction is due to combined interaction of FA and GGBS, which indicates that FA has lower reactivity than GGBS under ambient conditions. There is only small interaction of fly ash and GGBS probably due to different kinetics of dissolution process and distribution of species. Puligulla et al.[39] studied GGBS-FA blend pastes. They found that the calcium that dissolves from slag significantly influences both early and late age properties. The availability of free Ca ions seems to prolong FA dissolution and enhance geopolymer gel formation. It is proposed that the hardening process is initiated by the precipitation of C-A-S-H and that rapid hardening continues due to accelerated geopolymerization. Liu et al. 5The studies mentioned above reveal that, under particular conditions, mixing two different precursors cangive very interesting results. However, these studies have usually focused on the identification of a particular property under particu...

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“…As the Na2O content increases the bulk density decreases due to the formation Na. rich CSH with low bulk density and high porosity [41,42]. with the temperature as well as alkali content from AA1 up to AA2 and then decreases at AA3.…”

Section: Bulk Densitymentioning

confidence: 99%

Alkali Activation of Ceramic Waste

Nassar

Mostafa

Saraya

et al. 2010

Al-Azhar Bulletin of Science

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In ceramic tile production, because of various reasons, unsold fired products come out. These are waste tiles and only a little part of them are used. If these waste tiles were used in geopolymer production, this pollution decreases. In this study, usage of waste tile as pozzolan was studied. In this paper the effect of sodium silicate solution with different molar ratio on the compressive strength the synthesis of Egyptian ceramic waste -based geopolymers is investigated. Eight different alkaline solutions with different soluble silica contents were used to activate ceramic waste. The primary reaction product was a sodium aluminosilicate gel, while different types of zeolites appeared as minority phases. The percentage and composition of these reaction products were found to depend on both the soluble silica content present in the activating solutions and curing time. In addition, the amount of gel was observed to have a decisive effect on the mechanical strength developing in the material. X-ray diffract grams of geopolymers indicated the existence of the major amorphous phases of ceramic waste, as well as the formation of a new amorphous phase in the geopolymeric matrices. Fouriertransform infrared (FTIR) spectroscopy analysis revealed essential ceramic waste phase transformations within geopolymers that affected their mechanical strength. The results of the current research indicate that a compressive strength is increased with the increase of alkali content, as well as with the increase of sodium silicate in the synthesis of geopolymers.

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Influence of curing schedule on the integrity of geopolymers

Cited by 187 publications

References 12 publications

Production of nepheline/quartz ceramics from geopolymer mortars

Production of nepheline/quartz ceramics from geopolymer mortars

Formulation and characterization of blended alkali-activated materials based on flash-calcined metakaolin, fly ash and GGBS

Alkali Activation of Ceramic Waste

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