Rheological Behavior of Cement Pastes from MRI Velocimetry

Cement pastes are colloidal suspensions in which particle interactions lead to the formation of various microstructures. This article presents a rheological study of the behavior of cement pastes that uses a Couette viscometer inserted in a magnetic resonance imaging (MRI) device. This enables it possible for researchers to measure the local velocity field during transient and steady state flows. Such MRI measurements found that in a flowing cement paste, the thixotropic effects dominate over short time scales, while aging effects become significant over larger timescales. The steady state behavior exhibits a yielding behavior. This behavior differs from the prediction of usual yield stress models. The transition from the “solid” to the “liquid” regime is abrupt, meaning that the shear rate suddenly changes from zero to a finite value (critical shear rate) when the shear stress overcomes a critical value. These critical shear rates and shear stresses are independent of the flow conditions, and may thus be considered as intrinsic material parameters. These results are consistent with usual macroscopic observations from conventional rheometry. While this study primarily focused on steady state properties, time effects were also identified, and further studies will analyze these transient effects at a local scale and interpret them in a thixotropic model.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00088846
• Authors:
  • Jarny, S
  • Roussel, Nicolas
  • Rodts, S
  • Bertrand, F
  • Le Roy, R
  • Coussot, P
• Publication Date: 2005-10

Language

• English

Media Info

• Media Type: Print
• Features: Figures; Photos; References;
• Pagination: pp 1873-1881
• Serial:
  • Cement and Concrete Research
  • Volume: 35
  • Issue Number: 10
  • Publisher: Elsevier
  • ISSN: 0008-8846
  • Serial URL: http://www.sciencedirect.com/science/journal/00088846

Subject/Index Terms

• TRT Terms: Cement paste; Critical values; Physical properties; Rheological properties; Shear rate; Shear stress; Steady state; Thixotropy; Velocimeters; Yield stress
• Uncontrolled Terms: Magnetic resonance imaging
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 01011031
• Record Type: Publication
• Files: TRIS
• Created Date: Nov 22 2005 7:04PM