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Hydration and Expansion Characteristics of MgO Expansive Agent in Mass Concrete

Based on the underground reinforced concrete wall of subway stations (Hangzhou, China), this paper studied the influence of a MgO expansive agent (MEA) on deformation and mechanical properties of a reinforced concrete wall. The results show that the effect of the MEA with different activities to com...

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Autores principales: Jiang, Feifei, Mao, Zhongyang, Yu, Lanqing
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9694037/
https://www.ncbi.nlm.nih.gov/pubmed/36431514
http://dx.doi.org/10.3390/ma15228028
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author Jiang, Feifei
Mao, Zhongyang
Yu, Lanqing
author_facet Jiang, Feifei
Mao, Zhongyang
Yu, Lanqing
author_sort Jiang, Feifei
collection PubMed
description Based on the underground reinforced concrete wall of subway stations (Hangzhou, China), this paper studied the influence of a MgO expansive agent (MEA) on deformation and mechanical properties of a reinforced concrete wall. The results show that the effect of the MEA with different activities to compensate for the shrinkage of reinforced concrete walls is different. For MEA-R (60 s), because the activity is too high, its hydration rate is too fast, and many expansions occur at the plastic state of the concrete, which cannot effectively compensate for the shrinkage of concrete. For MEA-S (220 s), due to its low activity, the early hydration rate is so slow that it cannot compensate for the shrinkage, but it compensates well at the later stage due to the continuous hydration expansion of MEA. For MEA-M (140 s), the shrinkage of concrete is well compensated for the shrinkage at the early, middle and late stages due to its moderate activity. After using MEA to partially replace fly ash and mineral powder, the compressive strength of concrete was lower at the early stage (0–28 days). However, in the later stage, the porosity of concrete decreased rapidly, and the compressive strength of concrete would also be significantly improved. Therefore, choosing a suitably active MEA can compensate for the shrinkage of mass concrete without reducing its strength.
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spelling pubmed-96940372022-11-26 Hydration and Expansion Characteristics of MgO Expansive Agent in Mass Concrete Jiang, Feifei Mao, Zhongyang Yu, Lanqing Materials (Basel) Article Based on the underground reinforced concrete wall of subway stations (Hangzhou, China), this paper studied the influence of a MgO expansive agent (MEA) on deformation and mechanical properties of a reinforced concrete wall. The results show that the effect of the MEA with different activities to compensate for the shrinkage of reinforced concrete walls is different. For MEA-R (60 s), because the activity is too high, its hydration rate is too fast, and many expansions occur at the plastic state of the concrete, which cannot effectively compensate for the shrinkage of concrete. For MEA-S (220 s), due to its low activity, the early hydration rate is so slow that it cannot compensate for the shrinkage, but it compensates well at the later stage due to the continuous hydration expansion of MEA. For MEA-M (140 s), the shrinkage of concrete is well compensated for the shrinkage at the early, middle and late stages due to its moderate activity. After using MEA to partially replace fly ash and mineral powder, the compressive strength of concrete was lower at the early stage (0–28 days). However, in the later stage, the porosity of concrete decreased rapidly, and the compressive strength of concrete would also be significantly improved. Therefore, choosing a suitably active MEA can compensate for the shrinkage of mass concrete without reducing its strength. MDPI 2022-11-14 /pmc/articles/PMC9694037/ /pubmed/36431514 http://dx.doi.org/10.3390/ma15228028 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
Jiang, Feifei
Mao, Zhongyang
Yu, Lanqing
Hydration and Expansion Characteristics of MgO Expansive Agent in Mass Concrete
title Hydration and Expansion Characteristics of MgO Expansive Agent in Mass Concrete
title_full Hydration and Expansion Characteristics of MgO Expansive Agent in Mass Concrete
title_fullStr Hydration and Expansion Characteristics of MgO Expansive Agent in Mass Concrete
title_full_unstemmed Hydration and Expansion Characteristics of MgO Expansive Agent in Mass Concrete
title_short Hydration and Expansion Characteristics of MgO Expansive Agent in Mass Concrete
title_sort hydration and expansion characteristics of mgo expansive agent in mass concrete
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9694037/
https://www.ncbi.nlm.nih.gov/pubmed/36431514
http://dx.doi.org/10.3390/ma15228028
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