Effect of fly ash/silica fume ratio and curing condition on mechanical properties of fiber-reinforced geopolymer

Journal article

Authors/Editors

Strategic Research Themes

Publication Details

Author list: Sukontasukkul P., Chindaprasirt P., Pongsopha P., Phoo-Ngernkham T., Tangchirapat W., Banthia N.

Publisher: Elsevier

Publication year: 2020

Journal: Applied Clay Science (0169-1317)

Volume number: 9

Issue number: 4

Start page: 218

End page: 232

Number of pages: 15

ISSN: 0169-1317

eISSN: 1872-9053

URL: https://www.scopus.com/record/display.uri?eid=2-s2.0-85077864997&origin=resultslist&sort=plf-f&src=s&st1=Effect+of+fly+ash%2fsilica+fume+ratio+and+curing+condition+on+mechanical+properties+of+fiber-reinforced+geopolymer&sid=81e2539fad7f12a92b39be8499ffa732&sot=b&sdt=b&sl=127&s=TITLE-ABS-KEY%28Effect+of+fly+ash%2fsilica+fume+ratio+and+curing+condition+on+mechanical+properties+of+fiber-reinforced+geopolymer%29&relpos=0&citeCnt=13&searchTerm=

Languages: English-Great Britain (EN-GB)

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Abstract

In this study, a magnesium (Mg) and aluminum (Al) layered double hydroxide (LDH) was used as a precursor in the preparation of calcium (Ca), Mg and Al ternary mixed oxides for selective conversion of glycerol into diglycerols via solvent-free glycerol etherification. The LDH-derived MgAl mixed oxide was saturated with an aqueous solution of Ca citrate complexes, followed by calcination at 700 °C, to obtain the Ca-MgAl mixed metal oxide (MMO) catalysts. The effects of the citric acid addition and Ca loading levels on the physicochemical and catalytic properties of the resulting Ca-MgAl MMO were investigated. The Ca-MgAl MMO series were characterized by a high Ca dispersion, high total basicity (236–482 μmol g −1 ), an enhanced amount of strong basic sites and a new mesoporosity. The highest diglycerols selectivity of 78.3 mol% was achieved at a glycerol conversion of 40.4 mol% when the reaction was performed over the Ca-MgAl MMO catalyst synthesized with a 7.5 wt% Ca loading level, at a 3 wt% catalyst loading, 220 °C for 24 h. The formation of ternary mixed oxides improved the structural stability of the pristine MgAl mixed oxide. The catalytic performance of Ca-MgAl MMO was compared with that of commercial MgAl mixed oxides and homogeneous base (Na 2 CO 3 ). The presence of strong basicity in the MMO catalysts was a key part in the selective synthesis of diglycerols. © 2019 Elsevier B.V.

Keywords

Ca–Mg–Al mixed oxides, Diglycerols, Etherification, Layered double hydroxides