Rheological Interpretation of the Slump Test

Baudez, J.C.; Chabot, Frédéric; Coussot, Philippe

doi:10.1515/arh-2002-0008

Cited by 28 publications

(9 citation statements)

References 7 publications

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“…This phenomenon is almost negligible in highly concentrated mixtures but predominantly observed in less concentrated mixtures. From Baudez et al (2002), it is known that the plane surface roughness does not influence the slump height S of the unyielded central part. However, the influence of roughness on the profile of deposit has not been investigated yet.…”

Section: Rheometrymentioning

confidence: 99%

Rheometry for large-particulated fluids: analysis of the ball measuring system and comparison to debris flow rheometry

et al. 2009

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For large-particulated fluids encountered in natural debris flow, building materials, and sewage treatment, only a few rheometers exist that allow the determination of yield stress and viscosity. In the present investigation, we focus on the rheometrical analysis of the ball measuring system as a suitable tool to measure the rheology of particulated fluids up to grain sizes of 10 mm. The ball measuring system consists of a sphere that is dragged through a sample volume of approximately 0.5 l. Implemented in a standard rheometer, torques exerted on the sphere and the corresponding rotational speeds are recorded within a wide measuring range. In the second part of this investigation, six rheometric devices to determine flow curve and yield stress of fluids containing large particles with maximum grain sizes of 1 to 25 mm are compared, considering both rheological data and application in practical use. The large-scale rheometer of Coussot and Piau, the building material learning viscometer of Wallevik and Gjorv, and the ball measuring system were used for the flow curve determination and a capillary rheometer, the inclined plane test, and the slump test were used for the yield stress determination.For different coarse and concentrated sediment-water mixtures, the flow curves and the yield stresses agree well, except for the capillary rheometer, which exhibits much larger yield stress values. Differences are also noted in the measuring range of the different devices, as well as for the required sample volume that is crucial for application.

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Section: Rheometrymentioning

confidence: 99%

Rheometry for large-particulated fluids: analysis of the ball measuring system and comparison to debris flow rheometry

et al. 2009

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“…We mainly used a commercial hair gel (Yplon S.A., Belgium), basically made of water and Carbopol, with the internal structure of a physical gel of density close to that of water. Previous studies showed that this material exhibits the rheological behavior of a typical yield stress fluid with a flow curve, which may well be represented by a Herschel-Bulkley model (Baudez et al 2002). Here the yield stress, as determined from a series of creep tests at different levels with a parallel plate rheometer (see Baudez et al 2002), was found to be 70 Pa. To change the yield stress value we also used suspensions of Carbopol ® 940 (ACROS Organics, France) at different solid fractions, prepared according to the procedure described in Curran et al (2002).…”

Section: Experimental Setup and Proceduresmentioning

confidence: 93%

Flow of a yield stress fluid over a rotating surface

Tabuteau¹,

Baudez²,

Château

et al. 2006

Rheol Acta

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We study the flow of yield stress fluids over a rotating surface when both the viscoelastic solid behavior below a critical deformation (γ c) and liquid properties beyond γ c can play a significant role. We review the detailed characteristics of the flow in the solid regime in the specific case of a pure elongational strain (large height to radius ratio). We, in particular, show that there exists a critical rotation velocity (ω c) associated with the transition from the solid to the liquid regime. We then consider the specific case of lubricational regime (small height to radius ratio) in the liquid regime. In that case we describe the different possible evolutions of the equilibrium shape of the material as a function of the rotation velocity (ω), from which we extrapolate the transient shape evolutions as ω increases. We show that for a sufficiently large rotation velocity the sample separates into two parts, one remaining at rest around the rotation axis, the other going on moving radially. These predictions are then compared with systematic spin-coating tests under increasing rotation velocity ramps followed by a plateau at ω f with typical yield stress fluids. It appears that there exists a critical velocity below which the material undergoes a limited elongation and beyond which it starts to spread significantly over the solid surface. For a larger ω f value the sample forms a thick peripheral roll, leaving behind it a thin layer of fluid at rest relatively to the disc. These characteristics are in qualitative agreement with the theoretical predictions. Beyond a sufficiently large ω f value this roll eventually spreads radially in the form of thin fingers. Moreover, in agreement with the theory in the lubricational regime, the different curves of deformation vs ω fall along a master curve when the rotation velocity is scaled by ω c for different accelerations, different sample radii, or different material yield stress. The final thickness of the deposit seems to be mainly governed by the displacement of the roll, the characteristics of which take their origin in the initial stage of the spreading, including the solid-liquid transition.

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“…A comparison of these theoretical predictions with experimental results was rather successful, even if there remained a significant uncertainty on the exact determination of the yield stress. A comprehensive comparison between rheometric measurements and slump test results has appeared elsewhere (Baudez et al, 2002).…”

Section: Practical Determination Of the Yield Stress With The Slump Testmentioning

confidence: 99%

“…Since in general pasty sewage sludge have higher yield stresses than fresh concrete, we proposed a modification of the slump test (Baudez et al, 2002), i.e. an additional mass is placed at the top of the sample, which assures that small sample volumes can still be used (Fig.…”

Section: Practical Determination Of the Yield Stress With The Slump Testmentioning

confidence: 99%