Reference: C. Ferraris, F. de Larrard and N. Martys, Materials Science of Concrete VI, S. Mindess and J. Skalny, eds., 215-241 (2001).

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Fresh Concrete Rheology - Recent Developments

C. Ferraris, F. de Larrard and N. Martys

Abstract

The design of concrete with specified properties for an application is not a new science, but it has taken on a new meaning with the wide use of high performance concretes (HPC). The following properties are related to fresh concrete: "ease of placement" and "compaction without segregation." The term, ease of placement, covers various other properties of fresh concrete that are called: workability, flowability, compactibility, stability, finishability, pumpability, and/or consistency. These words are often used interchangeably without a definition based on fundamental measurements of properties. Several attempts were made to better relate fresh concrete properties with measurable entities. Some researchers treated fresh concrete as a fluid and used the fluid rheology methods to describe concrete flow. This approach, the most fundamental one, is reviewed in this paper.

The main topics that will be addressed are:

• Review the fundamental definitions of entities used to uniquely describe the flow of concrete
• An overview of tests that are commonly used to measure the rheology of fresh concrete.
• Methods to predict the flow of concrete from either composition or laboratory tests
• The main parameters that affect the flow of fresh concrete, such as composition, placement and mixing methods
• Two special applications of rheology: pumpable concrete and self-compacting concrete

• Introduction
• Concrete flow using rheological parameters
• Measurement techniques for fresh concrete
• Models to predict rheological properties
  • Compressible Packing Model (CPM)
  • Simulation of flow of suspensions
  • Krieger-Dougherty modified model
• Factors affecting the rheology of concrete
• Pumpable concrete
  • Practical problems dealing with concrete pumping
  • Tribology of steel/concrete interfaces
  • The CALIBE project
• Self-Consolidating Concrete
• Conclusion
• References