Comparison of Concrete Rheometers: International Tests at MB (Cleveland, OH, USA) in May 2003.
Comparison of Concrete Rheometers: International Tests
at MB (Cleveland, OH, USA) in May 2003.
(1985 K)
Ferraris, C. F.; Brower, L. E.; Beaupre, D.;
Chapdelaine, F.; Domone, P.; Koehler, E. P.; Shen, L.;
Sonebi, M.; Struble, L.; Tepke, D.; Wallevik, O.;
Wallevik, J. E.
NISTIR 7154; 47 p. September 2004.
Keywords:
rheometers; cements; oils; mortar; concretes; rheology
Abstract:
The American Concrete Institute (ACI) sub-committee
236A, "Workability of Fresh Concrete" upon its creation
in fall 1999, immediately faced the task of determining
appropriate methods to measure concrete workability.
Using a material science-based approach, workability
should be defined using rheological methods. The
instrument most used for determining rheological
parameters is a rheometer. There are several concrete
rheometers used around the world that have significant
design differences, but no standard method with which to
compare their results. ACI 236A members determined that,
as no reference material was available, one method to
compare the rheometers would be to test them under the
same conditions using the same concrete mixtures. A
tentative analysis comparing two rheometers was
performed but did not involve most of the available
rheometer designs. A first set of round-robin testing
was organized in 2000, allowing the direct comparison of
five types of rheometers. This first comparison test was
sponsored by the Concrete Research Council (CRC) of ACI
and by industry. It was held at the Laboratoire Central
des Ponts et Chaussees (LCPC) facility in Nantes,
France, on October 23-27, 2000. The rheometers selected
included commercially available concrete rheometers
(four), and one coaxial concrete rheometer developed for
research. After the test and subsequent report it was
apparent that some issues were still unresolved;
therefore ACI 236A committee requested an extension
grant from CRC and more industrial support to conduct a
second set of round-robin testing. The second test was
performed on May 19-23, 2003, in the laboratory of
Masters Builders, a Degussa Construction Chemical
company, in Cleveland OH, (USA). The authors of this
report are principal investigators who participated in
this second test and contributed to the report. This
report describes the tests performed and the results
obtained. Following the same procedure as in the first
comparison test, this report was not published as an ACI
document and therefore was not submitted to the
Technical Activities Committee (TAC) for approval. There
are two reasons that this is not an ACI document: 1) ACI
documents are guidelines and practice recommendations,
not research reports; 2) all ACI reports are consensus
documents balloted and approved by the members of a
committee, while this report only reflects the views and
opinions of the authors. All members of ACI 236A were
invited to review the document prior to publication (as
shown in the acknowledgements). It was also discussed
during the regular meetings of ACI 236A during Fall 2003
and Spring 2004.
