Thermal stability of one-part metakaolin geopolymer composites containing high volume of spodumene tailings and glass wool
Lemougna, Patrick N.; Adediran, Adeolu; Yliniemi, Juho; Ismailov, Arnold; Levanen, Erkki; Tanskanen, Pekka; Kinnunen, Paivo; Röning, Juha; Illikainen, Mirja (2020-08-28)
Patrick N. Lemougna, Adeolu Adediran, Juho Yliniemi, Arnold Ismailov, Erkki Levanen, Pekka Tanskanen, Paivo Kinnunen, Juha Roning, Mirja Illikainen, Thermal stability of one-part metakaolin geopolymer composites containing high volume of spodumene tailings and glass wool, Cement and Concrete Composites, Volume 114, 2020, 103792, ISSN 0958-9465, https://doi.org/10.1016/j.cemconcomp.2020.103792
© 2020 The Authors. Published by Elsevier Ltd. his is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
https://creativecommons.org/licenses/by-nc-nd/4.0/
https://urn.fi/URN:NBN:fi-fe2020111290023
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Abstract
This paper deals with the synthesis and thermal stability of one-part metakaolin geopolymer composites containing high volume of spodumene tailings (Quartz Feldspar Sand; QFS) and glass wool (GW). One of the objectives of the study was to prepare materials encompassing a maximum amount of waste streams with some potential thermal stability. Several compositions were prepared with sodium metasilicate anhydrous (Na2SiO3) wt.% of 0.5, 2.5, 5, 10 and 12,5. The one-part metakaolin geopolymer composites were cured at 60 °C for 24 h and the mechanical properties were assessed at 7 days and after post-heat treatment at 500, 750, 1000, 1100 or 1200 °C. X-ray diffraction, dilatometry, scanning electron microscopy and thermogravimetry analyses were used to study the stability of the prepared geopolymer composites until 1100–1200 °C. The results showed that more than 20 MPa compressive strength could be achieved with metakaolin geopolymer composites containing only 20 wt% of metakaolin. Metakaolin-GW geopolymer composites were stable up to 500 °C. Meanwhile, their counterparts containing QFS were stable up to 1100–1200 °C; samples prepared with higher dosage of sodium (Na2SiO3 > 5 wt%) retained more than 50% of their initial strength after thermal treatment at 1100 °C. Interestingly, for dosages of Na2SiO3 ≤ 5 wt%, more than 300% increase of strength was observed after thermal treatment at 1100–1200 °C. The use of QFS limited the thermal shrinkage at mild temperatures (<1000 °C), but favoured densification and strength development at 1100–1200 °C.
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