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Open AccessArticle

XRD and TG-DTA Study of New Alkali Activated Materials Based on Fly Ash with Sand and Glass Powder

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Faculty of Materials Science and Engineering, “Gheorghe Asachi” Technical University, Blvd. D. Mangeron 71, 700050 Iasi, Romania
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Romanian Inventors Forum, Str. Sf. P. Movila 3, 700089 Iasi, Romania
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National Institute for Research and Development in Environmental Protection, 294 Splaiul Independenței Blv, 060031 Bucharest, Romania
*
Authors to whom correspondence should be addressed.
Materials 2020, 13(2), 343; https://doi.org/10.3390/ma13020343
Received: 18 November 2019 / Revised: 16 December 2019 / Accepted: 8 January 2020 / Published: 11 January 2020
(This article belongs to the Special Issue Obtaining and Characterization of New Materials)
In this paper, the effect on thermal behavior and compounds mineralogy of replacing different percentages of fly ash with compact particles was studied. A total of 30% of fly ash was replaced with mass powder glass (PG), 70% with mass natural aggregates (S), and 85% with mass PG and S. According to this study, the obtained fly ash based geopolymer exhibits a 20% mass loss in the 25–300 °C temperature range due to the free or physically bound water removal. However, the mass loss is closely related to the particle percentage. Multiple endothermic peaks exhibit the dihydroxylation of β-FeOOH (goethite) at close to 320 °C, the Ca(OH)2 (Portlandite) transformation to CaCO3 (calcite) occurs at close to 490 °C, and Al(OH)3 decomposition occurs at close to 570 °C. Moreover, above 600 °C, the curves show only very small peaks which may correspond to Ti or Mg hydroxides decomposition. Also, the X-ray diffraction (XRD) pattern confirms the presence of sodalite after fly ash alkaline activation, whose content highly depends on the compact particles percentage. These results highlight the thermal stability of geopolymers in the 25–1000 °C temperature range through the use of thermogravimetric analysis, differential thermal analysis, and XRD. View Full-Text
Keywords: geopolymers; fly ash; thermal behavior; Thermogravimetry-Differential Thermal Analysis (TG-DTA); XRD geopolymers; fly ash; thermal behavior; Thermogravimetry-Differential Thermal Analysis (TG-DTA); XRD
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Burduhos Nergis, D.D.; Abdullah, M.M.A.B.; Sandu, A.V.; Vizureanu, P. XRD and TG-DTA Study of New Alkali Activated Materials Based on Fly Ash with Sand and Glass Powder. Materials 2020, 13, 343.

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