Use of Municipal Solid Waste Incineration Fly Ash in Geopolymer Masonry Mortar Manufacturing |
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Authors: | Ning Lu Xin Ran Zhu Pan Asghar Habibnejad Korayem |
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Affiliation: | 1.College of Safety Engineering, Chongqing University of Science and Technology, Chongqing 401331, China;2.School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin 300130, China;3.Centre for Infrastructure Engineering, Western Sydney University, Penrith, NSW 2747, Australia;4.School of Civil Engineering, Iran University of Science and Technology, Tehran 1684613114, Iran |
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Abstract: | The feasibility of partially replacing pulverized fly ash (PFA) with municipal solid waste incineration fly ash (MSWIFA) to produce ambient-cured geopolymers was investigated. The influence of mixture design parameters on the compressive strength of geopolymer paste was studied. The investigated parameters included MSWIFA dosage, the ratio of sodium silicate to sodium hydroxide (SS/SH), the ratio of liquid to solid (L/S) alkaline activator, and the ratio of SH molar. A water immersion method was selected as a pretreatment process for MSWIFA, leading to effectively maintaining the volume stability of the MSWIFA/PFA geopolymer. The mixture of 30% treated MSWIFA and 70% PFA with 12 M SS, 0.5 L/S ratio, and 3.0 SS/SH ratio produced the highest three-day compressive strength (4.9 MPa). Based on the optimal paste mixture, category four masonry mortars (according to JGJT98-2011) were prepared to replace various ratios of natural sand with fine recycling glasses. Up to a 30% replacement ratio, the properties of the mortars complied with the limits established by JGJT98-2011. The twenty-eight-day leaching rate of mortars containing 30% MSWIFA was lower than the limits proposed by GB5085.3-2007. Microstructural analysis indicated that the main reaction product was a combination of calcium silicate hydrate gel and aluminosilicate gel. |
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Keywords: | pretreatment heavy metal leachability alkali-aggregate reaction recycling glass microstructure |
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