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Modified Slump Test to Measure Rheological Parameters of Fresh Concrete.


pdf icon Modified Slump Test to Measure Rheological Parameters of Fresh Concrete. (844 K)
Ferraris, C. F.; deLarrard, F.

Cement,Concrete, and Aggregates, Vol. 20, No. 2, 241-247, December 1998.

Keywords:

concretes; concrete rheology; slump test; plastic viscosity; yield stress; workability field test

Abstract:

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.