Evolution of a natural pozzolan-based geopolymer alkalized in the presence of sodium or potassium silicate/hydroxide solution

González-García, Dulce María; Téllez-Jurado, Lucía; Jiménez-Álvarez, F.J.; Zarazúa-Villalobos, L.; Balmori‐Ramírez, Heberto

doi:10.1016/j.conbuildmat.2021.126305

Cited by 21 publications

(7 citation statements)

References 27 publications

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“…precursors, including natural pozzolan-derived geopolymers, basalt and slag composites, and coal gangue-based geopolymeric sources, demonstrate enhanced mechanical performance without the need for additional alkali-activated Al2O3 (Akturk and Ayhan, 2023;González-García et al, 2022;. In raw materials with very low SiO2 content, optimizing the system may require incorporating additional silicon and aluminum oxides, such as metakaolin and granulated blast furnace slag (GGBS) (Lahoti et al, 2017;Paramasivan and Rajagopal, 2023;X.…”

Section: Introductionmentioning

confidence: 99%

Factors Influencing the Mechanical Properties and Reaction Kinetics of Wasted Ultrabasic Tuff Used as a Binder

Zhang,

Hou,

Cui

et al. 2024

Preprint

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Ultrabasic tuff powder, a solid waste generated from manufactured sand and aggregate production without calcination treatment, contains less than 45% SiO2 stabilized in aluminosilicate. Due to its high crystallinity, few studies have explored its viability as a raw material for binder preparation. Using an orthogonal experimental design, this study revealed the impacts of three key factors on the mechanical properties of ultrabasic tuff-based binder (UTB): the mass ratio of silica to alumina (S/A), the mass ratio of sodium oxide (Na2O) to binders (N/B), and curing temperature (T). To elucidate the reaction kinetics, an array of analytical techniques, including Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDS), were employed. The results indicate that an increase in S/A and T enhanced the dissolution degree of precursors, along with improved compressive strengths. Conversely, an increase in N/B led to a minimal reduction in the dissolution degree, with compressive strengths initially rising and then declining. The optimal combination of three factors was S/A = 5, N/B = 0.10, and T = 80°C, resulting in a maximum compressive strength exceeding 80.0 MPa. The ratio of dissolved silicon (Si) to aluminum (Al) was approximately 50:1, signifying a composition profoundly different from traditional alkali-activated binders. Additionally, the proportions of dissolved silica (SiO2) and alumina (Al2O3) were determined to be 46.38% and 4.48% of the total, respectively, suggesting that UTB comprised both reactive and unreactive components. The reactive portion, consisting of quartz, calcite, chlorite, and silica fume, forms an amorphous (N, C)-A-S-H gel, connecting with the unreactive part.

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Section: Introductionmentioning

confidence: 99%

Factors Influencing the Mechanical Properties and Reaction Kinetics of Wasted Ultrabasic Tuff Used as a Binder

Zhang,

Hou,

Cui

et al. 2024

Preprint

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“…NaOH not only has a higher dissolving capacity, but it is also cheaper and more environmentally friendly than KOH. 46 As for alkali solution molarity, if its concentration is low, sufficient strength cannot be achieved, and if it is high, the strength decreases again. [47][48][49] Curing temperature and time are other important parameters that affect the resulting GP structure.…”

Section: Introductionmentioning

confidence: 99%

“…The choice of alkaline solution is another key issue in terms of the aluminosilicate dissolution, especially in the first stage of geopolymerization. NaOH not only has a higher dissolving capacity, but it is also cheaper and more environmentally friendly than KOH 46 . As for alkali solution molarity, if its concentration is low, sufficient strength cannot be achieved, and if it is high, the strength decreases again 47–49 .…”

Section: Introductionmentioning

confidence: 99%

Sustainable activation of pumice with partially variable substitutions of metakaolin and/or fumed silica

Bagci,

Kafkas,

Samuel

et al. 2023

Int J Applied Ceramic Tech

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Sustainable alkali activation of pumice from Turkish origin was studied by a partial replacement of metakaolin and/or fumed silica additives. Following the characterization of as‐received pumice by X‐ray fluorescence spectroscopy, x‐ray diffraction, and nuclear magnetic resonance spectroscopy, a series of powder mixtures were prepared by introducing metakaolin and/or fumed silica (8, 14, and 20 M) into 1 M of the pumice. The mixtures were then dissolved in 11 M NaOH or sodium silicate solutions. The slurries were poured into polyacetal molds to obtain geopolymer samples for mechanical testing and cured in a constant 50°C temperature in a humidity oven for 48 h and then left for 1 week to undergo additional curing at ambient temperature. The microstructural, mechanical, and thermal properties of the final geopolymer samples were determined by XRD, scanning electron microscopy, Weibull analysis of 3‐point flexural and compressive tests and thermal conductivity measurements. Results showed that all the Weibull values were best for 14 M of metakaolin and/or fumed silica. The metakaolin‐added pumice yielded higher compressive strengths of (53.78 ± 33.30 MPa) than fumed silica (10.87 ± 4.04 MPa) and fumed silica plus metakaolin (41.22 ± 5.16 MPa). Thermal conductivities (0.19–0.46 Wm–1K–1) were also comparable to the thermal conductivity of metakaolin‐based geopolymers.

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“…This is feasible as long as the waste is a potential source of aluminosilicates, such as coal fly ash [22], slag from metallurgical processes [23], metakaolin [24], glass waste [25], bagasse [26] and even hazardous [27]. In turn, these aluminosilicates must be alkaline activated, using, in most investigations, sodium hydroxide [28] or potassium hydroxide [29] solutions in the appropriate proportions.…”

Section: Introductionmentioning

confidence: 99%

Factor Analysis of the Physical–Mechanical Properties for Geopolymers Based on Brick Dust and Biomass Bottom Ash as Eco-Friendly Building Materials

Terrones-Saeta,

Luís,

Romero

et al. 2023

Processes

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The production of building materials is unavoidable if the well-being and development of society are to be maintained. However, in manufacturing these materials, significant greenhouse gas emissions and environmental effects are produced. For this reason, and with the aim of reducing the impact of the manufacture of these materials, this work developed a geopolymeric material made up solely of wastes, brick dust and biomass bottom ashes which replaced the traditional ceramic materials. To evaluate the quality of this sustainable geopolymeric material, different groups of specimens were formed with different percentages of both residues, subsequently determining the physical properties of the new-formed geopolymers and guaranteeing they accomplish the prescriptions of the ceramic regulations for construction. In addition, the results of the geopolymer characterisation tests were statistically analysed using factor analysis, with the sole purpose of establishing connections and interdependence between the variables that influence the geopolymerisation process. Thus, it was possible to demonstrate that the combination of brick dust and biomass bottom ashes produced geopolymers with adequate qualities to replace traditional ceramics, as well as that the different combinations of both residues produced feasible materials to be used as ceramics with various characteristics, with two main factors determined by factorial analysis that governed the physical properties of the geopolymer obtained: the percentage of brick dust and the theoretical porosity.

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Evolution of a natural pozzolan-based geopolymer alkalized in the presence of sodium or potassium silicate/hydroxide solution

Cited by 21 publications

References 27 publications

Factors Influencing the Mechanical Properties and Reaction Kinetics of Wasted Ultrabasic Tuff Used as a Binder

Factors Influencing the Mechanical Properties and Reaction Kinetics of Wasted Ultrabasic Tuff Used as a Binder

Sustainable activation of pumice with partially variable substitutions of metakaolin and/or fumed silica

Factor Analysis of the Physical–Mechanical Properties for Geopolymers Based on Brick Dust and Biomass Bottom Ash as Eco-Friendly Building Materials

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