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Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement
To improve the mechanical performance and lower the production cost of magnesium oxysulfate cement (MOSC), this article investigates the effects of single and compounded addition of metakaolin (MK) and/or fly ash (FA) on the setting time, mechanical strength, water resistance, hydration product, com...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8874730/ https://www.ncbi.nlm.nih.gov/pubmed/35207882 http://dx.doi.org/10.3390/ma15041334 |
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author | Liu, Tong Li, Chunqing Li, Li Fan, Wenqiang Dong, Yudong Liang, Huihui Yang, Hongjian |
author_facet | Liu, Tong Li, Chunqing Li, Li Fan, Wenqiang Dong, Yudong Liang, Huihui Yang, Hongjian |
author_sort | Liu, Tong |
collection | PubMed |
description | To improve the mechanical performance and lower the production cost of magnesium oxysulfate cement (MOSC), this article investigates the effects of single and compounded addition of metakaolin (MK) and/or fly ash (FA) on the setting time, mechanical strength, water resistance, hydration product, composition, and microstructure of the resulting cement. MOSC samples with different proportions, ranging from 0 to 30 wt.%, of FA and/or MK substituting magnesium oxide (MgO) were prepared. The microstructure was explored by scanning electron microscopy, X-ray diffraction, and mercury intrusion porosimetry. The findings suggest that adding FA can delay the setting of MOSC; however, the effect of adding MK to MOSC was reversed. Furthermore, the phase composition of the MOSC hydration products was unaltered upon adding FA and/or MK, but thicker and longer 517 phase crystals were observed. FA and MK can effectively fill the large pores of MOSC through filling and nucleation effects, reduce the pore size, and form a denser microstructure, thereby improving its mechanical properties. The optimal MOSC sample was found by substituting 10 wt.% of both FA and MK, resulting in a cement that exhibited a short setting time and an incredibly high mechanical strength and density. These findings will further the development of stronger, more cost-efficient, and more water-resistant MOSC products. |
format | Online Article Text |
id | pubmed-8874730 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-88747302022-02-26 Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement Liu, Tong Li, Chunqing Li, Li Fan, Wenqiang Dong, Yudong Liang, Huihui Yang, Hongjian Materials (Basel) Article To improve the mechanical performance and lower the production cost of magnesium oxysulfate cement (MOSC), this article investigates the effects of single and compounded addition of metakaolin (MK) and/or fly ash (FA) on the setting time, mechanical strength, water resistance, hydration product, composition, and microstructure of the resulting cement. MOSC samples with different proportions, ranging from 0 to 30 wt.%, of FA and/or MK substituting magnesium oxide (MgO) were prepared. The microstructure was explored by scanning electron microscopy, X-ray diffraction, and mercury intrusion porosimetry. The findings suggest that adding FA can delay the setting of MOSC; however, the effect of adding MK to MOSC was reversed. Furthermore, the phase composition of the MOSC hydration products was unaltered upon adding FA and/or MK, but thicker and longer 517 phase crystals were observed. FA and MK can effectively fill the large pores of MOSC through filling and nucleation effects, reduce the pore size, and form a denser microstructure, thereby improving its mechanical properties. The optimal MOSC sample was found by substituting 10 wt.% of both FA and MK, resulting in a cement that exhibited a short setting time and an incredibly high mechanical strength and density. These findings will further the development of stronger, more cost-efficient, and more water-resistant MOSC products. MDPI 2022-02-11 /pmc/articles/PMC8874730/ /pubmed/35207882 http://dx.doi.org/10.3390/ma15041334 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Liu, Tong Li, Chunqing Li, Li Fan, Wenqiang Dong, Yudong Liang, Huihui Yang, Hongjian Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement |
title | Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement |
title_full | Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement |
title_fullStr | Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement |
title_full_unstemmed | Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement |
title_short | Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement |
title_sort | effect of fly ash and metakaolin on properties and microstructure of magnesium oxysulfate cement |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8874730/ https://www.ncbi.nlm.nih.gov/pubmed/35207882 http://dx.doi.org/10.3390/ma15041334 |
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