Topic
Geopolymer
About: Geopolymer is a research topic. Over the lifetime, 6776 publications have been published within this topic receiving 157991 citations. The topic is also known as: geopolymers.
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TL;DR: In this paper, a mixture of metakaolin and alkali solution at a fixed ratio at room temperature and then pre-crashed to a fixed-radius size was used to make a geopolymer for heavy metal adsorption.
318 citations
TL;DR: Aluminosilicate geopolymers with SiO2/Al2O3 ratios ranging from 0.5 to 300 have been prepared from mixtures of dehydroxylated kaolinite with either ρ-Al 2O3 or fine Aerosil SiO 2, with the ratios Na2O/SiO2 and H2O /SiO 2 kept constant throughout the series as mentioned in this paper.
Abstract: Aluminosilicate geopolymers with SiO2/Al2O3 ratios ranging from 0.5 to 300 have been prepared from mixtures of dehydroxylated kaolinite with either ρ-Al2O3 or fine Aerosil SiO2, with the ratios Na2O/SiO2 and H2O/SiO2 kept constant throughout the series. All the compositions hardened at ambient temperature, but the high-alumina compositions were of low strength and did not display typical XRD and NMR geopolymer characteristics, by contrast with the compositions of S/A between 2 and 300 which showed typical amorphous geopolymer XRD traces and 27Al, 29Si and 23Na NMR spectra. The samples with increasing SiO2 content (S/A > 24) showed increasingly elastic behaviour, deforming rather than crushing in brittle fashion, and upon heating at 100–250 °C, their hydration water was expelled as bubbles, forming stable foamed materials at about 300 °C.
318 citations
TL;DR: In this article, the performance of geopolymer concrete when exposed to 2% sulfuric acid solution for more than a year was compared to OPC concrete which is attributed to a more stable cross-linked aluminosilicate polymer structure formed in the geopolymers concrete.
317 citations
TL;DR: In this article, the effects of sodium hydroxide and sodium silicate solutions on the properties of fly ash (FA)-granulated blast furnace slag (GBFS) geopolymer were investigated.
314 citations
TL;DR: In this paper, the pore structure of fly-ash-based geopolymers was studied using electron microscopy and porosimetry, showing that higher curing temperature increases the extent and rate of reaction, shown through an increase in mesopore volume, surface area, and an accelerated setting time.
Abstract: The development of the pore structure of geopolymers synthesized from class F fly ash was studied using electron microscopy and porosimetry. Fly-ash-based geopolymer can be classified as a mesoporous aluminosilicate material, with a Si/Al composition varying from 1.51 to 2.24. The Si/Al composition and pore structure of fly-ash-based geopolymer vary depending on the curing temperature and the silicate ratio of the activating solutions (SiO2/M2O, M = Na or K). A higher Si/Al ratio and finer pores are obtained in geopolymers synthesized at higher temperature and silicate ratios. Elevating the curing temperature increases the extent and rate of reaction, shown through an increase in mesopore volume, surface area, and an accelerated setting time. The kinetics appears to be temperature-controlled only before the material is hardened. Very high silicate ratios (SiO2/M2O ≥ 2.0) are also believed to slow the reactions. The pore structure of K-based geopolymer is more susceptible to change in temperature than that...
310 citations