NIST Time|NIST Home|About NIST|Contact NIST

HomeAll Years:AuthorKeywordTitle2005-2010:AuthorKeywordTitle

Relating Fresh Concrete Viscosity Measurements From Different Rheometers.


pdf icon 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.

Available from:

FOR MORE INFORMATION CONTACT:
Website: 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.