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...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-04-01
|
| Series: | Materials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1944/16/9/3448 |
| _version_ | 1797602248486813696 |
|---|---|
| author | Xuan Zhou Zhongyang Mao Penghui Luo Min Deng |
| author_facet | Xuan Zhou Zhongyang Mao Penghui Luo Min Deng |
| author_sort | Xuan Zhou |
| collection | DOAJ |
| 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<sup>−6</sup>, 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<sup>−6</sup>, respectively. Overall, the concrete with a total compounding of 30% and a compounding ratio of 2:1 has the best shrinkage resistance performance. |
| first_indexed | 2024-03-11T04:14:19Z |
| format | Article |
| id | doaj.art-93172bd1e680440dbfe8567a492b6311 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-11T04:14:19Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-93172bd1e680440dbfe8567a492b63112023-11-17T23:16:13ZengMDPI AGMaterials1996-19442023-04-01169344810.3390/ma16093448Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO ConcreteXuan Zhou0Zhongyang Mao1Penghui Luo2Min Deng3College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211800, ChinaCollege of Materials Science and Engineering, Nanjing Tech University, Nanjing 211800, ChinaCollege of Materials Science and Engineering, Nanjing Tech University, Nanjing 211800, ChinaCollege of Materials Science and Engineering, Nanjing Tech University, Nanjing 211800, ChinaShrinkage 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<sup>−6</sup>, 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<sup>−6</sup>, respectively. Overall, the concrete with a total compounding of 30% and a compounding ratio of 2:1 has the best shrinkage resistance performance.https://www.mdpi.com/1996-1944/16/9/3448mineral admixtureMEAfly ashmineral powderself-shrinkagecompressive strength |
| spellingShingle | Xuan Zhou Zhongyang Mao Penghui Luo Min Deng Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete Materials mineral admixture MEA fly ash mineral powder self-shrinkage compressive strength |
| 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 | mineral admixture MEA fly ash mineral powder self-shrinkage compressive strength |
| url | https://www.mdpi.com/1996-1944/16/9/3448 |
| work_keys_str_mv | AT xuanzhou effectofmineraladmixturesonthemechanicalandshrinkageperformanceofmgoconcrete AT zhongyangmao effectofmineraladmixturesonthemechanicalandshrinkageperformanceofmgoconcrete AT penghuiluo effectofmineraladmixturesonthemechanicalandshrinkageperformanceofmgoconcrete AT mindeng effectofmineraladmixturesonthemechanicalandshrinkageperformanceofmgoconcrete |