ISSN: 0149-6123
Page Count: 7

Modified Slump Test to Measure Rheological Parameters of Fresh Concrete
Ferraris, CF
National Institute of Standards and Technology, MD

de Larrard, F
Laboratoire Central des Ponts et Chaussées,

(Received 14 July 1998; accepted 11 February 1998)

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.

Keywords:
concrete rheology, slump test, plastic viscosity, yield stress, workability field test

Paper ID: CCA10417J
DOI: 10.1520/CCA10417J
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