Details
| Originalsprache | Englisch |
|---|---|
| Aufsatznummer | 1853 |
| Fachzeitschrift | MATERIALS |
| Jahrgang | 13 |
| Ausgabenummer | 8 |
| Publikationsstatus | Veröffentlicht - 2 Apr. 2020 |
Abstract
The rheological properties of fresh cement paste are highly influenced by a large number of parameters, among which the most important factors are the applied shear stress, and the shear history, the age of the sample and the temperature. The effects of these parameters on the yield stress (designated as structural limit stress in this work), the viscosity and the structural recovery rate (i.e., the change in dynamic viscosity with time at rest) were studied. In parallel, the changes in ion composition of the carrier liquid, mineral phase content and granulometry were investigated. The results reveal that all investigated rheological parameters exhibit an approximated bi-linear trend with respect to the degree of hydration, with a period of quasi-constant properties until a degree of hydration of approximately 0.07, followed by a non-linear increase. This increase could be attributed to the formation of calcium hydroxide (CH) and calcium-silicate-hydrate (C-S-H) via calorimetry results. With regard to the effect of the shear history of the sample on the rheological properties, the structural limit stress showed a minor dependency on the shear history immediately after the end of shearing, which, however, vanished within the first minute at rest. The same is true for the structural recovery rate. The presented results give detailed insights into the influences of hydration and shear on the rheological properties-especially the thixotropy-of fresh cement pastes.
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in: MATERIALS, Jahrgang 13, Nr. 8, 1853, 02.04.2020.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - The influences of cement hydration and temperature on the thixotropy of cement paste
AU - Link, J.
AU - Sowoidnich, T.
AU - Pfitzner, C.
AU - Gil-Diaz, T.
AU - Heberling, F.
AU - Lützenkirchen, J.
AU - Schäfer, T.
AU - Ludwig, H.-M.
AU - Haist, M.
N1 - Funding Information: This research was funded by Deutsche Forschungsgmeinschaft (DFG) under the grants HA 7917/3-1, SCHA 1854/4-1 and LU 1652/32-1 within the DFG priority programme 2005 “Opus Fluidum Futurum—Rheology of reactive, multiscale, multiphase construction materials.” Acknowledgments: The authors thank HeidelbergCement AG and BASF Construction Solutions GmbH for providing the cement and superplasticers within the priority programme 2005. The publication of this article was funded by the Open Access Fund of the Leibniz Universität Hannover.
PY - 2020/4/2
Y1 - 2020/4/2
N2 - The rheological properties of fresh cement paste are highly influenced by a large number of parameters, among which the most important factors are the applied shear stress, and the shear history, the age of the sample and the temperature. The effects of these parameters on the yield stress (designated as structural limit stress in this work), the viscosity and the structural recovery rate (i.e., the change in dynamic viscosity with time at rest) were studied. In parallel, the changes in ion composition of the carrier liquid, mineral phase content and granulometry were investigated. The results reveal that all investigated rheological parameters exhibit an approximated bi-linear trend with respect to the degree of hydration, with a period of quasi-constant properties until a degree of hydration of approximately 0.07, followed by a non-linear increase. This increase could be attributed to the formation of calcium hydroxide (CH) and calcium-silicate-hydrate (C-S-H) via calorimetry results. With regard to the effect of the shear history of the sample on the rheological properties, the structural limit stress showed a minor dependency on the shear history immediately after the end of shearing, which, however, vanished within the first minute at rest. The same is true for the structural recovery rate. The presented results give detailed insights into the influences of hydration and shear on the rheological properties-especially the thixotropy-of fresh cement pastes.
AB - The rheological properties of fresh cement paste are highly influenced by a large number of parameters, among which the most important factors are the applied shear stress, and the shear history, the age of the sample and the temperature. The effects of these parameters on the yield stress (designated as structural limit stress in this work), the viscosity and the structural recovery rate (i.e., the change in dynamic viscosity with time at rest) were studied. In parallel, the changes in ion composition of the carrier liquid, mineral phase content and granulometry were investigated. The results reveal that all investigated rheological parameters exhibit an approximated bi-linear trend with respect to the degree of hydration, with a period of quasi-constant properties until a degree of hydration of approximately 0.07, followed by a non-linear increase. This increase could be attributed to the formation of calcium hydroxide (CH) and calcium-silicate-hydrate (C-S-H) via calorimetry results. With regard to the effect of the shear history of the sample on the rheological properties, the structural limit stress showed a minor dependency on the shear history immediately after the end of shearing, which, however, vanished within the first minute at rest. The same is true for the structural recovery rate. The presented results give detailed insights into the influences of hydration and shear on the rheological properties-especially the thixotropy-of fresh cement pastes.
KW - Cement paste
KW - Hydration
KW - Opus fluidum futurum
KW - Rheology
KW - Thixotropy
UR - http://www.scopus.com/inward/record.url?scp=85084574668&partnerID=8YFLogxK
U2 - 10.3390/MA13081853
DO - 10.3390/MA13081853
M3 - Article
VL - 13
JO - MATERIALS
JF - MATERIALS
SN - 1996-1944
IS - 8
M1 - 1853
ER -