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Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete

Shrinkage deformation of concrete has been one of the difficulties in the process of concrete performance research. Cracking of concrete caused by self-shrinkage and temperature-drop shrinkage has become a common problem in the concrete world, and cracking leads to a decrease in the durability of co...

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Autores principales: Zhou, Xuan, Mao, Zhongyang, Luo, Penghui, Deng, Min
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10180498/
https://www.ncbi.nlm.nih.gov/pubmed/37176329
http://dx.doi.org/10.3390/ma16093448
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author Zhou, Xuan
Mao, Zhongyang
Luo, Penghui
Deng, Min
author_facet Zhou, Xuan
Mao, Zhongyang
Luo, Penghui
Deng, Min
author_sort Zhou, Xuan
collection PubMed
description Shrinkage deformation of concrete has been one of the difficulties in the process of concrete performance research. Cracking of concrete caused by self-shrinkage and temperature-drop shrinkage has become a common problem in the concrete world, and cracking leads to a decrease in the durability of concrete and even a safety hazard. Mineral admixtures, such as fly ash and mineral powder, are widely used to improve the temperature drop shrinkage of mass concrete; fly ash can reduce the temperature rise of concrete while also reducing the self-shrinkage of concrete, there are different results on the effect of mineral powder on the self-shrinkage of concrete, but the admixture of fly ash will reduce the strength of concrete, and mineral admixtures have an inhibitory effect on the shrinkage compensation effect of MgO expander(MEA). The paper investigates the effect of mineral admixtures on the mechanical and deformation properties of C50 mass concrete with a MgO expander(MEA), aiming to determine the proportion of C50 mass concrete with good anti-cracking properties under working conditions. The experiments investigated the effect of fly ash admixture, mineral powder admixture and MgO expander admixture on the compressive strength and deformation of concrete under simulated working conditions of variable temperature and analyzed the effect of hydration of magnesite in MgO expander and pore structure of cement paste on deformation. The following main conclusions were obtained: 1. When the concrete compounded with mineral admixture was cured under variable temperature conditions, the compounded 30% fly ash and mineral powder decreased by 4.3%, 6.0% and 8.4% at 7d age, and the compounded 40% fly ash and mineral powder decreased by 3.4%, 2.8% and 2.3% at 7d age, respectively. The incorporation of MEA reduced the early compressive strength of concrete; when the total amount of compounding remained unchanged, the early compressive strength of concrete was gradually smaller as the proportion of compounding decreased. 2. The results of concrete deformation showed that when the temperature rose, the concrete expanded rapidly, and when the temperature dropped, the concrete also showed a certain shrinkage, and the deformation of concrete basically reached stability at 18d. 3. The compounding of 30% fly ash and mineral powder As the compounding ratio decreases, the deformation of concrete increases, and the 28d deformation of concrete with a compounding ratio of 2:1 is 280 × 10(−6), while the final stable deformation of concrete with a compounding ratio of 2:1 in compounding 40% fly ash and mineral powder is the largest, with a maximum value of 230 × 10(−6), respectively. Overall, the concrete with a total compounding of 30% and a compounding ratio of 2:1 has the best shrinkage resistance performance.
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spelling pubmed-101804982023-05-13 Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete Zhou, Xuan Mao, Zhongyang Luo, Penghui Deng, Min Materials (Basel) Article Shrinkage deformation of concrete has been one of the difficulties in the process of concrete performance research. Cracking of concrete caused by self-shrinkage and temperature-drop shrinkage has become a common problem in the concrete world, and cracking leads to a decrease in the durability of concrete and even a safety hazard. Mineral admixtures, such as fly ash and mineral powder, are widely used to improve the temperature drop shrinkage of mass concrete; fly ash can reduce the temperature rise of concrete while also reducing the self-shrinkage of concrete, there are different results on the effect of mineral powder on the self-shrinkage of concrete, but the admixture of fly ash will reduce the strength of concrete, and mineral admixtures have an inhibitory effect on the shrinkage compensation effect of MgO expander(MEA). The paper investigates the effect of mineral admixtures on the mechanical and deformation properties of C50 mass concrete with a MgO expander(MEA), aiming to determine the proportion of C50 mass concrete with good anti-cracking properties under working conditions. The experiments investigated the effect of fly ash admixture, mineral powder admixture and MgO expander admixture on the compressive strength and deformation of concrete under simulated working conditions of variable temperature and analyzed the effect of hydration of magnesite in MgO expander and pore structure of cement paste on deformation. The following main conclusions were obtained: 1. When the concrete compounded with mineral admixture was cured under variable temperature conditions, the compounded 30% fly ash and mineral powder decreased by 4.3%, 6.0% and 8.4% at 7d age, and the compounded 40% fly ash and mineral powder decreased by 3.4%, 2.8% and 2.3% at 7d age, respectively. The incorporation of MEA reduced the early compressive strength of concrete; when the total amount of compounding remained unchanged, the early compressive strength of concrete was gradually smaller as the proportion of compounding decreased. 2. The results of concrete deformation showed that when the temperature rose, the concrete expanded rapidly, and when the temperature dropped, the concrete also showed a certain shrinkage, and the deformation of concrete basically reached stability at 18d. 3. The compounding of 30% fly ash and mineral powder As the compounding ratio decreases, the deformation of concrete increases, and the 28d deformation of concrete with a compounding ratio of 2:1 is 280 × 10(−6), while the final stable deformation of concrete with a compounding ratio of 2:1 in compounding 40% fly ash and mineral powder is the largest, with a maximum value of 230 × 10(−6), respectively. Overall, the concrete with a total compounding of 30% and a compounding ratio of 2:1 has the best shrinkage resistance performance. MDPI 2023-04-28 /pmc/articles/PMC10180498/ /pubmed/37176329 http://dx.doi.org/10.3390/ma16093448 Text en © 2023 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
Zhou, Xuan
Mao, Zhongyang
Luo, Penghui
Deng, Min
Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete
title Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete
title_full Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete
title_fullStr Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete
title_full_unstemmed Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete
title_short Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete
title_sort effect of mineral admixtures on the mechanical and shrinkage performance of mgo concrete
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10180498/
https://www.ncbi.nlm.nih.gov/pubmed/37176329
http://dx.doi.org/10.3390/ma16093448
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