Modified Slump Test to Measure Rheological Parameters of Fresh Concrete.
Modified Slump Test to Measure Rheological Parameters of
Ferraris, C. F.; deLarrard, F.
Cement,Concrete, and Aggregates, Vol. 20, No. 2,
241-247, December 1998.
concretes; concrete rheology; slump test; plastic
viscosity; yield stress; workability field test
The ease of placement of concrete depends upon at least
two physical properties, the yield stress and plastic
viscosity. Currently the most common field test is the
slump test, and it is related only to the yield stress.
Therefore, a simple field test method intended to
provide an evaluation of the two Bingham rheological
parameters, yield stress and plastic viscosity, was
developed. To determine the plastic viscosity the time
necessary for the upper surface of the concrete in the
standard slump cone to slump 100 mm was measured. The
apparatus and test procedure are described.
Semi-empirical models are proposed for the yield stress
and for the plastic viscosity as function of the final
slump and slumping time. The application of the
modified slump test for the evaluation of the viscosity
is limited to concretes with a slump of 120 to 260 mm.
If the validity of this test is confirmed in the future,
it could be used as a field quality control test.