Properties of NaOH activated geopolymer with marble, travertine and volcanic tuff wastes

Tekin, İlker

doi:10.1016/j.conbuildmat.2016.10.038

Cited by 103 publications

(68 citation statements)

References 18 publications

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“…The individual content is presented in Table 1 on a m% basis. As shown, Sample (3) contains similar chemical composition with the industrial sample (0) while the other four samples (1,2,4,5) are utilized as the contrastive sample by adjusting SiO 2 /Al 2 O 3 ratios. Since the furnace desulfurization is conducted in CFB by adding CaO into the feeding system, the basic/acid ratio (B/A) of CFB fly ash is higher than that of the conventional combustion.…”

Section: Synthetic Coal Ash Samples Preparationmentioning

confidence: 99%

“…The temperature of the muffle furnace is below 1473 K and the accuracy of it is ±20 K. Volume shrinkage ratio (VSR) represents the ratio between volume variation (∆V) and pre-reaction volume (V pre ) of the cuboid samples, as is shown in Equation (1).…”

Section: Volume Shrinkage Ratio (Vsr) Testmentioning

confidence: 99%

“…Meanwhile, because of high ash content, fine particle size, and good mechanical properties, the fly ash of CFB can be applied as alternative raw materials for construction materials (e.g., cement and geopolymer) [1][2][3]. However, ash deposition on the surface of the cyclone separator or the heat exchanger is an operational obstacle in combustion, which can adversely affect equipment performance.…”

Section: Introductionmentioning

confidence: 99%

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Effects of SiO2/Al2O3 Ratios on Sintering Characteristics of Synthetic Coal Ash

Zhou

Meng

et al. 2017

Energies

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This article explores the effects of SiO 2 /Al 2 O 3 ratios (S/A) on sintering characteristics and provides guidance for alleviating ash depositions in a large-scale circulation fluidized bed. Five synthetic coal ash (SCA) samples with different S/As were treated in a muffle furnace for 12 h at different temperatures (from 773 K to 1373 K, in 100 K intervals). The morphological and chemical results of the volume shrinkage ratio (VSR), thermal deformation analysis by dilatometer (DIL), scanning electron microscope (SEM), X-ray photoelectron spectrometer (XPS), and X-ray diffraction (XRD) were combined to describe the sintering characteristics of different samples. The results showed that the sintering procedure mainly occurred in the third sintering stage when the temperature was over 1273 K, accompanied with significant decreases in the VSR curve. Excess SiO 2 (S/A = 4.5) resulted in a porous structure while excess Al 2 O 3 (S/A = 0.5) brought out large aggregations. The other three samples (S/A = 1.5, 2.5, 3.5) are made up of an amorphous compacted structure and are composed of low fusion temperature materials (e.g., augite and wadsleysite.). Sintering temperatures first dramatically decrease to a low level and then gradually rise to a high level as S/A increases, suggesting that Al 2 O 3 -enriched additives are more effective than SiO 2 -enriched additives in alleviating depositions.

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Section: Synthetic Coal Ash Samples Preparationmentioning

confidence: 99%

Section: Volume Shrinkage Ratio (Vsr) Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of SiO2/Al2O3 Ratios on Sintering Characteristics of Synthetic Coal Ash

Zhou

Meng

et al. 2017

Energies

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“…Nonetheless, the production of cement lead to carbon dioxide (CO2) emission especially during clinker production [1]. Hence, due to the urge to produce eco-friendly binder, geopolymer or alkali activated cements was introduced by Davidovits in 1978 [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…The materials that rich in alumina and silicates such as fly ash, kaolinite and slag can be used in geopolymer as mineral sources. The reactivity of these sources depends on the chemical composition, particularly the content of silica oxide (SiO2), alumina oxide (Al2O3) and calcium oxide (CaO), the morphology of the particle shapes, phase of materials as well as the particle sizes [1]. Fly ash is generally considered as a waste material and it is a by-product of coal combustion process for electric power plant.…”

Section: Introductionmentioning

confidence: 99%

Comparative study on early strength of sodium hydroxide (NaOH) activated fly ash based geopolymer

Yahya

Talib

Razak

2017

AIP Conference Proceedings

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Abstract. The urge to reduce carbon dioxide (CO2) emission has encourage researchers to introduce environmental friendly binder or known as geopolymer. This new binder was produced by mixing source materials rich in silica and alumina with alkaline liquids. For this study, class F fly ash was used as source material with two different types of alkaline activator; sodium hydroxide (NaOH) only and a combination of water glass with NaOH. The different concentration of the NaOH solutions (8M, 10M, 12M and 14M) is used in the production of geopolymer. The parameters such as curing regime, solid/liquid ratio, and water glass/NaOH ratio are controlled in the study. The samples with combination of NaOH and water glass as alkaline activator were prepared by mixing these two solution and stirred for 2 minutes. Then this solution were mixed together with fly ash for 3 minutes and casted in the mould. The performance of the fly ash based geopolymer are evaluated by the compressive strength, water absorption and density at the early age of 1th, 3th and 7th days. Based on the study, at a concentration of 14M on 7th days had achieved the maximum compressive strength of 7.1 MPa for samples activated with NaOH only. Meanwhile, for geopolymer samples activated with a combination of the water glass and NaOH, the maximum strength of 33.33 MPa was recorded on 7th days of testing with NaOH concentration of 12 M. The water absorption for all geopolymer samples were ranging from 2.04 % to 2.78%, which are below the limit (3%). While the density of the geopolymer paste were in the range of 1552 kg/m3 to 1680 kg/m3, which are below the limit (2400 kg/m3). From the standpoint of strength of hardened geopolymer samples, the most effective alkaline activator in geopolymer is the combination of NaOH and water glass.

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Influence of various factors on properties of geopolymer paste: A comparative study

Kantarcı

Türkmen

Ekinci

2020

Structural Concrete

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A comprehensive experimental study was conducted to investigate effect of different production parameters such as activator type, activator concentration and curing temperature on fresh and hardened properties of volcanic tuff based geopolymer paste (GP) samples. Volcanic tuff obtained from Nevşehir (Central Anatolia, Turkey) was ground to particle size less than 45 μm, after that alkali activation process was provided with two type of alkali activators such as NaOH and NaOH+Na2SiO3 (SH and SH + SS) solutions. Produced geopolymer samples were cured at different temperatures ranging from 23 to 150°C. Compressive strength, setting time, hydration heat of GP samples were investigated. Additionally, microstructural investigations were performed with SEM and XRD analyzes. As a result of modification of experimental parameters, compressive strength development reached to 41.43 MPa was obtained from GP samples, which did not harden in laboratory conditions. It was also determined that the alkali activation of volcanic tuff with SH exhibited better mechanical and microstructural properties than alkali activation with SH + SS.

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Properties of NaOH activated geopolymer with marble, travertine and volcanic tuff wastes

Cited by 103 publications

References 18 publications

Effects of SiO2/Al2O3 Ratios on Sintering Characteristics of Synthetic Coal Ash

Effects of SiO2/Al2O3 Ratios on Sintering Characteristics of Synthetic Coal Ash

Comparative study on early strength of sodium hydroxide (NaOH) activated fly ash based geopolymer

Influence of various factors on properties of geopolymer paste: A comparative study

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