Doctoral Dissertations

Keywords and Phrases

Cement paste; Parallel plates; Rheology; Sedimentation; Testing procedure; Thixotropy

Abstract

“Rheology has been widely used to describe the flow properties of fresh cement-based suspensions. The use of a rheometer to characterize these properties is not a straightforward task due to the dependency to different preparation conditions, mixing processes, testing procedures and measuring instruments employed. In addition, shear and time dependency of the material which undergoes chemical and physical particle bonding, caused by hydration of cement and flocculation. Nevertheless, the characterization and understanding of the rheological behavior of cement-based materials have become essential with the recent introduction of novel applications like digital construction in the field of civil engineering, among others. Therefore, to be able to suitably adapt such properties, to optimize and to ensure consistent performance, there is a need to accurately measure the properties and to obtain repeatable and consistent results. This research work shows how changes in the testing procedure, rheometer geometry and resting time in between measurements impact the rheological properties of cement pastes. The results indicate that the time-evolution of the rheological properties is strongly dependent on the employed procedure, and the effect is attributed to shear-enhanced hydration. Also, the resting time enhances the increase in differential viscosity and is dependent on the admixture’s workability retention, as small or significant variations in the rheological properties are observed. The proper understanding of the advantages and disadvantages as well as the limitations of each geometry and procedure should be taken into account to avoid issues such as wall slip, sample spill, dryness, particles sedimentation, non-uniform shear rate applied, etc. that can be prevented”--Abstract, page iv.

Advisor(s)

Feys, Dimitri

Committee Member(s)

Kumar, Aditya
Schuman, Thomas P.
Juenger, Maria
Mendoza, Cesar

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

Ph. D. in Civil Engineering

Comments

The research team would like to acknowledge the University of Missouri Research Board (UMRB) and the Center for Infrastructure Studies (CIES) at Missouri S&T for the financial support and the use of the equipment.

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2020

Journal article titles appearing in thesis/dissertation

  • How do different testing procedures affect the rheological properties of cement paste?
  • Resting time effect on the rheological behavior of cement paste in the presence of superplasticizer
  • Challenges in Rheological Characterization of Cement Pastes Using a Parallel-Plates Geometry
  • Effect of sedimentation on the rheological properties of cement paste

Pagination

xv, 127 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2020 Aida Margarita Ley Hernandez, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11980

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