The influence of the NaOH solution on the properties of the fly ash-based geopolymer mortar cured at different temperatures

Görhan, Gökhan; Kürklü, Gökhan

doi:10.1016/j.compositesb.2013.10.082

Cited by 507 publications

(195 citation statements)

References 32 publications

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“…This finding is in agreement with the results of a previous study [41] where curing under elevated temperature was found to be beneficial in accelerating strength development. Görhan et al [42] highlighted that curing under elevated temperature leads to an increment of the compressive strength without significant effect on the physical characteristics.…”

Section: Comparisons With Heat Treated Specimensmentioning

confidence: 99%

Development of geopolymer mortar under ambient temperature for in situ applications

Al-Majidi

Λαμπρόπουλος

Cundy

et al. 2016

Construction and Building Materials

309

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Geopolymer concrete technology involves production of more environmentally friendly waste material-based concrete which could be a viable solution for conventional concrete replacement. Typical fly ash-based geopolymer concrete however requires high temperature curing treatment in order to develop sufficient early strength properties, which is considered a severe limitation for cast-in-place concrete applications. Most previous studies on geopolymer concrete have focused on the properties of concretes pre-hardened by heat curing and/ or by aggressive chemical treatment (e.g. alkali activation using concentrated sodium hydroxide (NaOH)). The current study presents an extensive experimental investigation on the mechanical and microstructural properties of geopolymer concrete mixes prepared with a combination of fly ash and slag cured under ambient temperature. 'User friendly' geopolymer mixes were produced using fly ash (FA) and Ground Granulated Blast furnace Slag (GGBS) mixed together with potassium silicate with molar ratio equal to 1.2 (as the activator) and water. The results indicated that heat curing treatment can be avoided by partial replacement of fly ash with slag. The compressive strength of the examined mixes was found to be in the range of 40-50MPa for 40 % and 50 % GGBS replacement mixtures respectively. Moreover, the flexural and direct tensile strengths of geopolymer mixes are considerably improved as the GGBS content is increased.Based on FTIR and SEM/EDS analysis, the inclusion of a higher content of GGBS resulted in a denser structure by formation of more hydration products.Keywords: Fly ash, slag, ambient temperature, user friendly geopolymer mortar *Manuscript Click here to view linked References 2 IntroductionThere are many environmental issues associated with the production of Ordinary Portland cement (OPC), such as consumption of 5% of natural resources, and generation of 5-7 % of total global anthropogenic carbon dioxide emissions [1][2][3][4]. This has led to an urgent need for the development of alternative materials that may provide technically viable alternative solutions to conventional cementitious concrete, with more favourable environmental credentials. Geopolymer concrete manufacture is one of the most promising techniques which has been developed in the last few years. Utilization of geopolymer materials can reduce 80% of greenhouse gas emissions associated with material production, and overcome issues related to cement production and unregulated disposal of industrial materials by recycling these materials in geopolymer manufacture [5][6][7].Geopolymers are inorganic by-product materials, rich in silicon (Si) and aluminium Five different mixtures of geopolymer mortar proportions were examined with various ratios of GGBS to total binder (10%, 20%, 30%, 40% and 50 %, Table 2). Based on preliminary experimental studies undertaken during the current project, the optimum mix design (in terms of mechanical strength and workability) was achieved using water, alkaline activator...

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Section: Comparisons With Heat Treated Specimensmentioning

confidence: 99%

Development of geopolymer mortar under ambient temperature for in situ applications

Al-Majidi

Λαμπρόπουλος

Cundy

et al. 2016

Construction and Building Materials

309

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“…An optimum Si/Al ratio increases the strength of the resulting geopolymer. Apart from the ideal ratio, some losses may occur in the mechanical properties of the material due to the change of the geopolymer structure [19].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Si/Al on Mechanical Properties and Fracture Behavior of Stainless Steel Mesh/Cr_pReinforced Geopolymer Composites

Yuan

Jia

2017

MATEC Web Conf.

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Abstract. In this study, a series stainless steel mesh/Cr p reinforced geopolymer composites with different Si/Al molar ratio (N) were designed and prepared, where N = 1.75, 2 and 2.25, respectively. The effect of Si/Al molar ratio in the geopolymer matrix on mechanical properties and fracture behavior of the geopolymer composites were investigated. The microstructure of geopolymer became more compact when Si/Al increased from 1.75 to 2, which was beneficial to the improvement of geopolymer's mechanical properties. And continuing to rise to 2.25 for Si/Al, the completely curing of geopolymer composites required more time compared with lower Si/Al, which can be attributed to the different microstructure and chemical composition caused by the different Si/Al. The optimum Si/Al molar ratio was about 2 at which the composites samples present the best mechanical properties with the flexure strength of 115.3 MPa and elastic modulus of 11.0 GPa, respectively. The results of fracture behavior suggested that geopolymer composites with N is 2.25 displayed the behavior characteristics of metal materials, which can be attributed to a poor integrated condition in interface between reinforcements and geopolymer matrix.

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“…As densidades dos corpos de prova apresentaram valores entre 1,51 e 1,63 g/cm 3 . Esses resultados foram de acordo com os encontrados em [25], em que os autores estudaram as propriedades físicas de geopolímeros à base de CV. A permeabilidade apresentou modificação significativa com a alteração da composição química da solução ativadora.…”

Section: Q (Grau)unclassified

Produção de geopolímeros à base de cinza volante usando soluções ativadoras com diferentes composições de Na2O e Na2SiO3

et al. 2017

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ResumoGeopolímeros são uma nova classe de ligantes inorgânicos que possuem alta resistência mecânica, inércia química e podem ser fabricados a partir de uma série de subprodutos da indústria. Nesse trabalho amostras de geopolímeros foram produzidas pela ativação da cinza volante proveniente do complexo termelétrico de Jorge Lacerda, SC. Diferentes ativadores alcalinos foram utilizados para a obtenção dos materiais com o intuito de se observar como a modificação da composição química das soluções influencia as propriedades finais dos geopolímeros. Os resultados obtidos demonstraram que os materiais possuem alta resistência à compressão nas primeiras horas de cura (28 MPa) e que aumenta para valores próximos de 48 MPa após 28 dias. Por meio da difração de raios X observou-se que tanto as cinzas originais quanto as amostras ativadas apresentaram fases minerais comumente encontradas nesse tipo de material. A espectroscopia no infravermelho demonstrou que em todas as amostras, independente da composição química da solução alcalina, modificações nas bandas originais encontradas na cinza volante foram observadas. Tais modificações estão diretamente envolvidas com o processo de geopolimerização. As propriedades físicas das amostras, tais como absorção de água, porosidade e permeabilidade, também tiveram modificações quando diferentes composições químicas foram utilizadas para se ativar as cinzas volantes. Palavras-chave: geopolímeros, cimento geopolimérico, cinza volante, ativação alcalina. Abstract Geopolymers are a new class of binder with high mechanical strength, chemical inertia and can be made of by-products. In this work fly ash from a Brazilian

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The influence of the NaOH solution on the properties of the fly ash-based geopolymer mortar cured at different temperatures

Cited by 507 publications

References 32 publications

Development of geopolymer mortar under ambient temperature for in situ applications

Development of geopolymer mortar under ambient temperature for in situ applications

The Effect of Si/Al on Mechanical Properties and Fracture Behavior of Stainless Steel Mesh/Cr_pReinforced Geopolymer Composites

Produção de geopolímeros à base de cinza volante usando soluções ativadoras com diferentes composições de Na2O e Na2SiO3

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The influence of the NaOH solution on the properties of the fly ash-based geopolymer mortar cured at different temperatures

Cited by 507 publications

References 32 publications

Development of geopolymer mortar under ambient temperature for in situ applications

Development of geopolymer mortar under ambient temperature for in situ applications

The Effect of Si/Al on Mechanical Properties and Fracture Behavior of Stainless Steel Mesh/CrpReinforced Geopolymer Composites

Produção de geopolímeros à base de cinza volante usando soluções ativadoras com diferentes composições de Na2O e Na2SiO3

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The Effect of Si/Al on Mechanical Properties and Fracture Behavior of Stainless Steel Mesh/Cr_pReinforced Geopolymer Composites