The Influences of Cement Hydration and Temperature on the Thixotropy of Cement Paste

Materials

Thomas Sowoidnich¹  Horst-Michael Ludwig¹  Christopher Pfitzner²  Michael Haist²  Julian Link²  Thorsten Schäfer³  Johannes Lützenkirchen⁴  Frank Heberling⁴  Teba Gil-Diaz⁴ 

[1] F.A. Finger-Insitute for Building Materials, Bauhaus University Weimar, Coudraystrasse 11, 99423 Weimar, Germany;Institute for Building Materials Science, Leibniz University Hannover, Appelstraße 9a, 30167 Hannover, Germany;Institute of Geosciences, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749 Jena, Germany;Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany;

关键词: rheology;    hydration;    thixotropy;    cement paste;    opus fluidum futurum;   

DOI  :  10.3390/ma13081853

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown