Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects
Fly ash with low glass content is often prohibited from use in concrete due to the low reactivity and/or the inclusion of contaminants. However, the scarcity of high-quality fly ash promotes the evaluation of the feasibility of using fly ash with low glass content (e.g., low-grade fly ash) in concre...
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| Format: | Article |
| Language: | English |
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Elsevier
2024-12-01
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| Series: | Cement |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666549224000288 |
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| author | Qingxu Jin Wenyu Liao Xiaoqiang Ni Hongyan Ma |
| author_facet | Qingxu Jin Wenyu Liao Xiaoqiang Ni Hongyan Ma |
| author_sort | Qingxu Jin |
| collection | DOAJ |
| description | Fly ash with low glass content is often prohibited from use in concrete due to the low reactivity and/or the inclusion of contaminants. However, the scarcity of high-quality fly ash promotes the evaluation of the feasibility of using fly ash with low glass content (e.g., low-grade fly ash) in concrete. This study proposes a decoupling method to quantitatively estimate the degree of reaction of fly ash with extremely low glass content, which partially replaces cement, and the degree of hydration of the hosting cement, simultaneously. The estimation is derived from the contents of calcium hydroxide and chemically bonded water in hydrated binary cement pastes, which can be determined by thermogravimetric analysis-based experiments and theoretically validated stoichiometric parameters. The results exhibit that the fly ash tends to retard the early-age hydration of cement but promotes its later-age hydration, resulting in a higher ultimate degree of reaction of cement than the reference paste. The microstructural and porosity evaluation shows that the fly ash, though has relatively low degrees of reaction due to its low glass content, can result in a more tortuous pore network of the hydrated pastes, which could be potentially more resistant to the penetration of water and aggressive chemicals. |
| format | Article |
| id | doaj-art-6e89b497622943ffab1d96745fd8d30c |
| institution | Kabale University |
| issn | 2666-5492 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Cement |
| spelling | doaj-art-6e89b497622943ffab1d96745fd8d30c2024-12-15T06:17:09ZengElsevierCement2666-54922024-12-0118100119Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effectsQingxu Jin0Wenyu Liao1Xiaoqiang Ni2Hongyan Ma3Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USADepartment of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65401, USADepartment of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USADepartment of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65401, USA; Corresponding author.Fly ash with low glass content is often prohibited from use in concrete due to the low reactivity and/or the inclusion of contaminants. However, the scarcity of high-quality fly ash promotes the evaluation of the feasibility of using fly ash with low glass content (e.g., low-grade fly ash) in concrete. This study proposes a decoupling method to quantitatively estimate the degree of reaction of fly ash with extremely low glass content, which partially replaces cement, and the degree of hydration of the hosting cement, simultaneously. The estimation is derived from the contents of calcium hydroxide and chemically bonded water in hydrated binary cement pastes, which can be determined by thermogravimetric analysis-based experiments and theoretically validated stoichiometric parameters. The results exhibit that the fly ash tends to retard the early-age hydration of cement but promotes its later-age hydration, resulting in a higher ultimate degree of reaction of cement than the reference paste. The microstructural and porosity evaluation shows that the fly ash, though has relatively low degrees of reaction due to its low glass content, can result in a more tortuous pore network of the hydrated pastes, which could be potentially more resistant to the penetration of water and aggressive chemicals.http://www.sciencedirect.com/science/article/pii/S2666549224000288Fly ashCementReaction kineticsThermogravimetric analysisDecoupling methodHydration |
| spellingShingle | Qingxu Jin Wenyu Liao Xiaoqiang Ni Hongyan Ma Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects Cement Fly ash Cement Reaction kinetics Thermogravimetric analysis Decoupling method Hydration |
| title | Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects |
| title_full | Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects |
| title_fullStr | Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects |
| title_full_unstemmed | Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects |
| title_short | Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects |
| title_sort | low grade fly ash in portland cement blends a decoupling approach to evaluate reactivity and hydration effects |
| topic | Fly ash Cement Reaction kinetics Thermogravimetric analysis Decoupling method Hydration |
| url | http://www.sciencedirect.com/science/article/pii/S2666549224000288 |
| work_keys_str_mv | AT qingxujin lowgradeflyashinportlandcementblendsadecouplingapproachtoevaluatereactivityandhydrationeffects AT wenyuliao lowgradeflyashinportlandcementblendsadecouplingapproachtoevaluatereactivityandhydrationeffects AT xiaoqiangni lowgradeflyashinportlandcementblendsadecouplingapproachtoevaluatereactivityandhydrationeffects AT hongyanma lowgradeflyashinportlandcementblendsadecouplingapproachtoevaluatereactivityandhydrationeffects |