Measurement of Rheological Properties of High Performance Concrete: State of the Art Report.
Measurement of Rheological Properties of High
Performance Concrete: State of the Art Report.
(1700 K)
Ferraris, C. F.
NISTIR 5869; 39 p. July 1996.
Available from:
National Technical Information Service
Order number: PB96-202338
Keywords:
building technology; rheology; cement paste; mortar;
concretes; rheology test methods; flow properties;
suspension; workability; measurements; prediction;
models
Abstract:
The rheology or flow properties of concrete in general
and of high performance concrete (HPC) in particular, is
important, because many factors such as ease of
placement, consolidation, durability, and strength
depend on the flow properties. Concrete that is not
properly consolidated may have defects like honeycombs,
air voids, and aggregate segregation. Such an important
performance attribute has triggered the design of
numerous test methods. Generally, the flow behavior of
concrete approximates that of a Bingham fluid.
Therefore, at least two parameters, yield stress and
viscosity, are necessary to characterize the flow.
Nevertheless, most methods measure only one parameter.
Prediction of the flow properties of concrete from its
composition or from the properties of its components is
not easy. No general model exists, although some
attempts have been made. This report gives an overview
of the flow properties of a fluid or a suspension,
followed by a critical review of the most often used
tests for concrete rheology. Particular attention is
given to tests that could be used for HPC. Tentative
definitions of terms such as workability, consistency
and rheological parameters are provided. An overview of
the most promising tests and models for cement paste is
given.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899