Relating Fresh Concrete Viscosity Measurements From Different Rheometers.
Relating Fresh Concrete Viscosity Measurements From
Different Rheometers.
(573 K)
Ferraris, C. F.; Martys, N. S.
Journal of Research of the National Institute of
Standards and Technology, Vol. 108, No. 3, 229-234,
May/June 2003.
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http://nvl.nist.gov/pub/nistpubs/jres/108/3/j83fer.pdf
Keywords:
concretes; viscosity; rheometers; dissipative particle
dynamics modeling; plastics; rheology
Abstract:
Concrete rheological properties need to be properly
measured and predicted in order to characterize the
workability of fresh concrete, including special
concretes such as self-consolidating concrete (SCC). It
was shown by a round-robin test held in 2000 [1,2] that
different rheometer designs gave different values of
viscosity for the same concrete. While empirical
correlation between different rheometers was possible,
for a procedure that is supposed to scientifically
improve on the empirical slump tests, this situation is
unsatisfactory. To remedy this situation, a new
interpretation of the data was developed. In this paper,
it is shown that all instruments tested could be
directly and quantitatively compared in terms of
relative plastic viscosity instead of the plastic
viscosity alone. This should eventually allow the
measurements from various rheometer designs to be
directly calibrated against known standards of plastic
viscosity, putting concrete rheometry and concrete
workability on a sounder materials science basis.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899