Fresh Concrete Rheology - Recent Developments .
Fresh Concrete Rheology - Recent Developments .
(1441 K)
Ferraris, C. F.; deLarrard, F.; Martys, N. S.
Materials Science of Concrete VI. Proceedings. American
Ceramic Society. December 2001, American Ceramic
Society, Westerville, OH, Mindess, S.; Skalny, J.,
Editor(s)(s), 215-241 pp, 2001.
Keywords:
concretes; rheology
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, flowabilitly, 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
quatities. Some researchers treated fresh concrete as a
fluid and used the fluid rheology methods to describe
concrete flow. This approach, the most fundamental ine,
is reviewed in this paper. The main topics addressed
are: Review the fundamental definitions of quantities
used to uniquely describe the flow of concrete. An
overview of the tests that are commonly used to measure
the rheology of fresh concrete. Methods to predict the
flow of concrete from either compositon 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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899