On the “Thixotropic” Behavior of Fresh Cement Pastes
Thixotropic behavior describes a time-dependent rheological behavior characterized by reversible changes. Fresh cementitious materials often require thixotropic behavior to ensure sufficient workability and proper casting without vibration. Non-thixotropic behavior induces a workability loss. Cement...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | Eng |
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| Online Access: | https://www.mdpi.com/2673-4117/3/4/46 |
| _version_ | 1797459438993408000 |
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| author | Youssef El Bitouri Nathalie Azéma |
| author_facet | Youssef El Bitouri Nathalie Azéma |
| author_sort | Youssef El Bitouri |
| collection | DOAJ |
| description | Thixotropic behavior describes a time-dependent rheological behavior characterized by reversible changes. Fresh cementitious materials often require thixotropic behavior to ensure sufficient workability and proper casting without vibration. Non-thixotropic behavior induces a workability loss. Cementitious materials cannot be considered as an ideal thixotropic material due to cement hydration, which leads to irreversible changes. However, in some cases, cement paste may demonstrate thixotropic behavior during the dormant period of cement hydration. The aim of this work is to propose an approach able to quantify the contribution of cement hydration during the dormant period and to examine the conditions under which the cement paste may display thixotropic behavior. The proposed approach consists of a succession of stress growth procedures that allow the static yield stress to be measured. For an inert material, such as a calcite suspension, the structural build-up is due to the flocculation induced by attractive Van der Waals forces. This structural build-up is reversible. For cement paste, there is a significant increase in the static yield stress due to cement hydration. The addition of superplasticizer allows the thixotropic behavior to be maintained during the first hours due to its retarding effect. However, an increase in the superplasticizer dosage leads to a decrease in the magnitude of the Van der Waals forces, which can erase the thixotropic behavior. |
| first_indexed | 2024-03-09T16:51:21Z |
| format | Article |
| id | doaj.art-eb9696178e714b17bb7333aede671011 |
| institution | Directory Open Access Journal |
| issn | 2673-4117 |
| language | English |
| last_indexed | 2024-03-09T16:51:21Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Eng |
| spelling | doaj.art-eb9696178e714b17bb7333aede6710112023-11-24T14:41:21ZengMDPI AGEng2673-41172022-12-013467769210.3390/eng3040046On the “Thixotropic” Behavior of Fresh Cement PastesYoussef El Bitouri0Nathalie Azéma1Laboratoire de Mécanique et Génie Civil, LMGC, IMT Mines Ales, University of Montpellier, CNRS, 34000 Montpellier, FranceLaboratoire de Mécanique et Génie Civil, LMGC, IMT Mines Ales, University of Montpellier, CNRS, 34000 Montpellier, FranceThixotropic behavior describes a time-dependent rheological behavior characterized by reversible changes. Fresh cementitious materials often require thixotropic behavior to ensure sufficient workability and proper casting without vibration. Non-thixotropic behavior induces a workability loss. Cementitious materials cannot be considered as an ideal thixotropic material due to cement hydration, which leads to irreversible changes. However, in some cases, cement paste may demonstrate thixotropic behavior during the dormant period of cement hydration. The aim of this work is to propose an approach able to quantify the contribution of cement hydration during the dormant period and to examine the conditions under which the cement paste may display thixotropic behavior. The proposed approach consists of a succession of stress growth procedures that allow the static yield stress to be measured. For an inert material, such as a calcite suspension, the structural build-up is due to the flocculation induced by attractive Van der Waals forces. This structural build-up is reversible. For cement paste, there is a significant increase in the static yield stress due to cement hydration. The addition of superplasticizer allows the thixotropic behavior to be maintained during the first hours due to its retarding effect. However, an increase in the superplasticizer dosage leads to a decrease in the magnitude of the Van der Waals forces, which can erase the thixotropic behavior.https://www.mdpi.com/2673-4117/3/4/46thixotropyyield stresscement pastehydrationsuperplasticizer |
| spellingShingle | Youssef El Bitouri Nathalie Azéma On the “Thixotropic” Behavior of Fresh Cement Pastes Eng thixotropy yield stress cement paste hydration superplasticizer |
| title | On the “Thixotropic” Behavior of Fresh Cement Pastes |
| title_full | On the “Thixotropic” Behavior of Fresh Cement Pastes |
| title_fullStr | On the “Thixotropic” Behavior of Fresh Cement Pastes |
| title_full_unstemmed | On the “Thixotropic” Behavior of Fresh Cement Pastes |
| title_short | On the “Thixotropic” Behavior of Fresh Cement Pastes |
| title_sort | on the thixotropic behavior of fresh cement pastes |
| topic | thixotropy yield stress cement paste hydration superplasticizer |
| url | https://www.mdpi.com/2673-4117/3/4/46 |
| work_keys_str_mv | AT youssefelbitouri onthethixotropicbehavioroffreshcementpastes AT nathalieazema onthethixotropicbehavioroffreshcementpastes |