53. Non-reversible time-dependent rheological properties of fresh SCC

Title: 53. Non-reversible time-dependent rheological properties of fresh SCC
Author(s): D. Feys, R. Verhoeven, G. De Schutter
Paper category : conference
Book title: 5th International RILEM Symposium on Self-Compacting Concrete
Editor(s): G. De Schutter and V. Boel
Print-ISBN: 978-2-35158-047-9
e-ISBN: 978-2-35158-088-2
Publisher: RILEM Publications SARL
Publication year: 2007
Pages: 359 - 364
Total Pages: 6
Nb references: 11
Language: English

Abstract: The study of the rheological properties of fresh Self Compacting Concrete is a very complex matter, also due to time-dependent properties. In order to apply a model, like the Bingham model, in a steady state condition all time dependent effects, both reversible and non-reversible, must be eliminated. In this way, most concrete samples are tested by decreasing the shear rate stepwise, in order to eliminate thixotropy as much as possible. But concrete in general has a loss of workability in time, which is affecting the rheological properties also. Samples tested at a different ages will not show equal rheological properties.
In this paper, the evolution of the yield stress, the plastic viscosity at a certain shear rate and the shear thickening behaviour are evaluated in a time window of 2 hours, based on the modified Bingham model. Each parameter shows a typical mathematical relationship with time, but the magnitude of the loss is dependent on the composition of the concrete and the temperature. Comparison of the evolution of slump flow and yield stress in function of time shows that there is no general correlation between these parameters.

Online publication: 2009-06-16
Publication type : full_text
Public price (Euros): 0.00