A clean approach to high-strength fly ash-based geopolymers: Multi-granular screening with NaAlO2 enhancement
The limited application of fly ash-based geopolymers in large-scale construction is primarily due to the slow evolution of compressive strength and low early-stage compressive strength. Our research counters this by introducing a method that harnesses the innate reactivity of finer fly ash (FF), sig...
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Published in | Journal of cleaner production Vol. 464; p. 142733 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
20.07.2024
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Subjects | |
Online Access | Get full text |
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Summary: | The limited application of fly ash-based geopolymers in large-scale construction is primarily due to the slow evolution of compressive strength and low early-stage compressive strength. Our research counters this by introducing a method that harnesses the innate reactivity of finer fly ash (FF), significantly enhancing the compressive strength. Experimental and characterization results suggest that the superior performance of FF-based geopolymer is attributable to its higher content of reactive silica-alumina components, an optimal ratio of soluble silica to alumina, and a greater specific surface area, which collectively facilitate the geopolymerization process. Adding just 15 wt% NaOH, the FF-based geopolymer attains a compressive strength of 58.81 MPa after 14 d and an additional 10 wt% NaAlO2 can increase compressive strength to 70.5 MPa, showcasing a method that circumvents the need for energy-intensive milling or activation treatments. For the coarser fractions, thermal activation at 550 °C for an hour markedly improves strength to 39.40 MPa, aligning it with traditionally processed fly ash. This breakthrough paves the way for cleaner, more energy-efficient, and more substantial geopolymer materials in modern construction.
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•Post-screened fine fly ash with amorphous aluminosilicates enhances the potency of low-alkali geopolymers.•NaAlO₂ enrichment optimizes silica-alumina ratio, boosting geopolymer strength.•Room temperature curing boosts sustainability and efficiency of fly ash-based geopolymers.•Screening tech enables clean, efficient fly ash utilization in geopolymer synthesis. |
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ISSN: | 0959-6526 1879-1786 |
DOI: | 10.1016/j.jclepro.2024.142733 |