Incorporation of Waste Glass as an Activator in Class-C Fly Ash/GGBS Based Alkali Activated Material

Sasui, Sasui; Kim, Gyu-Yong; Nam, Jeongsoo; Riessen, Arie van; Eu, Hamin; Chansomsak, Sant; Alam, Syed Fakhar; Cho, Churl-Hee

doi:10.3390/ma13173906

Cited by 12 publications

(5 citation statements)

References 43 publications

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“…In all samples containing glass, however, a raised background is visible, which may be caused by the presence of unreacted glass and the low degree of structural order of formed hydrated calcium silicates. Their structure may be similar to the C-S-H phase structure formed in natural conditions [45]. This confirms the observation that in the autoclaving process, the presence of reactive silica in the amorphous state increases the amount of the C-S-H phase, but at the same time, the transformation of this phase into a more stable form is hindered [46].…”

Section: Resultssupporting

confidence: 85%

“…Instead, the most intense peaks from calcite were observed, which may indicate a significant degree of carbonation. This may be the reason for this sample's low compressive strength performance, where the calcium binder has carbonated instead of reacting with the silica [45,46]. In addition, due to quartz sand, very intense quartz peaks are observed in this sample.…”

Section: Resultsmentioning

confidence: 94%

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Utilization of Waste Glass in Autoclaved Silica–Lime Materials

Borek

Czapik

2022

Materials

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This paper aims to investigate the possibility of using waste glass of different colours as a complete substitute for quartz sand in autoclaved silica–lime samples. On the one hand, this increases the possibility of recycling waste glass; on the other hand, it allows obtaining autoclaved materials with better properties. In this research, reference samples with quartz sand (R) and white (WG), brown (BG), and green (GG) waste container glass were made. Parameters such as compressive strength, bulk density, and water absorption were examined on all samples. The samples were examined using a scanning electron microscope with an energy dispersive spectroscopy detector (SEM/EDS) and subjected to X-ray diffraction (XRD) analysis. The WG samples showed 187% higher compressive strength, BG by 159%, and GG by 134% compared to sample R. In comparison to the reference sample, volumetric density was 16.8% lower for sample WG, 13.2% lower for BG, and 7.1% lower for GG. Water absorption increased as bulk density decreased. The WG sample achieved the highest water absorption value, 15.84%. An X-ray diffraction analysis confirmed the presence of calcite, portlandite, and tobermorite phases. Depending on the silica aggregate used, there were differences in phase composition linked to compressive strength. Hydrated calcium silicates with varying crystallisation degrees were visible in the microstructure image.

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Section: Resultssupporting

confidence: 85%

Section: Resultsmentioning

confidence: 94%

Utilization of Waste Glass in Autoclaved Silica–Lime Materials

Borek

Czapik

2022

Materials

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“…Previous studies showed that sodium silicate (Na 2 SiO 3 ) solutions are efficient activators for amorphous wollastonitic hydraulic binders (AWHs) [9]. However, the use of Na 2 SiO 3 can be challenging due to its corrosiveness [10] and significant environmental impact caused by its high embodied energy [11,12]. Hence, the production of a green, low-cost, and easy-to-use activator is necessary.…”

Section: Introductionmentioning

confidence: 99%

“…Sasui et al [11] synthesized an alkaline activator by dissolving waste glass powder in a 4 M NaOH solution and successfully enhanced the properties of class-C fly ash and ground granulated blast furnace slag. Moreover, they also reported that by increasing the amount of dissolved waste glass powder in the alkaline solution, a higher silicon concentration and increased reactivity were observed.…”

Section: Introductionmentioning

confidence: 99%

The Use of Solid Sodium Silicate as Activator for an Amorphous Wollastonitic Hydraulic Binder

Antunes,

Santos,

Pereira

et al. 2024

Materials

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To ensure the acceptable mechanical strength of amorphous wollastonitic hydraulic binders (AWHs), activation with a sodium silicate solution is necessary. However, the use of this type of activator increases the final cost and the complexity of the product’s overall use. In this work, we focus on enhancing the manufacturing of the alkaline activator by producing three Na2SiO3 powders using cost-effective raw materials. The procedure consisted of heating a mixture of NaOH pebbles with either sand, glass, or diatomite to a temperature of 330 °C for 2 h. After synthesis, the powders were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) techniques. Finally, mortars made with AWHs were activated using the synthesized powders that were added either as a solid or dissolved in an aqueous solution. The compressive strength results in these mortars show that the lab-made activators are competitive with the traditional sodium silicate activators. Furthermore, the synthetized activators can be added in either solid form or pre-dissolved in a solution. This innovative approach represents a more economical, sustainable and easy-to-use approach to enhancing the competitiveness of AWHs.

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“…Sasui et al used sieved WG powder dissolved in NaOH (4 M) solution in three different proportions, i.e., 10, 20 and 30 g per 100 mL of NaOH (4 M) solution to activate Class C fly ash/slag mixtures. The results showed that reactive Ca supplied from slag and the dissolved silica in the alkaline solution resulted in a homogeneous and compact matrix with low porosity and high mechanical strength [12]. Melele et al investigated reactive hardeners from rice husk ash and waste glass separately prepared by adding NaOH pellets, mixing with distilled water and stirring the solution for 30 min at 100 • C, to manufacture metakaolin-based geopolymer samples.…”

Section: Introductionmentioning

confidence: 99%

Chemical and Microstructural Properties of Fly Ash and Fly Ash/Slag Activated by Waste Glass-Derived Sodium Silicate

Bondar¹,

Vinai

2022

Crystals

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Sodium silicate is commonly used for activating alumina silicates to produce alkali-activated binders that can compete with conventional Portland cement in concrete. However, the cost and emissions related to activators can hinder the use of alkali-activated materials in the industry. The novel, waste-based activators have been developed in the last years, using Si-rich waste streams. Processing waste glass cullet not only reduces the glass landfill disposal but also allows the production of sodium silicate for alkali activation. In this article, the chemical and microstructural properties of neat fly ash and blended 60 fly ash/40 slag pastes activated by sodium silicate produced from glass cullet were studied and compared to equivalent ones activated by commercially available sodium silicate and sodium hydroxide solutions. Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) were used to determine the microstructure and composition of the gel phase. Findings have confirmed that pastes activated by the processed waste glass showed chemical and microstructural properties comparable to pastes produced with commercially available activators.

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Incorporation of Waste Glass as an Activator in Class-C Fly Ash/GGBS Based Alkali Activated Material

Cited by 12 publications

References 43 publications

Utilization of Waste Glass in Autoclaved Silica–Lime Materials

Utilization of Waste Glass in Autoclaved Silica–Lime Materials

The Use of Solid Sodium Silicate as Activator for an Amorphous Wollastonitic Hydraulic Binder

Chemical and Microstructural Properties of Fly Ash and Fly Ash/Slag Activated by Waste Glass-Derived Sodium Silicate

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