Reply to the discussion by Crowder and Grabinsky on "Assessment of the modified slump test as a measure of the yield stress of high-density thickened tailings"

2005 ◽  
Vol 42 (1) ◽  
pp. 319-320
Author(s):  
S KY Gawu ◽  
A B Fourie
Keyword(s):  
Yield Stress ◽  
High Density ◽  
Slump Test ◽  
Thickened Tailings

Assessment of the modified slump test as a measure of the yield stress of high-density thickened tailings

2004 ◽  
Vol 41 (1) ◽  
pp. 39-47 ◽  
Author(s):  
S KY Gawu ◽  
A B Fourie
Keyword(s):  
Yield Stress ◽  
Coaxial Cylinder ◽  
High Density ◽  
Simple Test ◽  
Shear Yield Stress ◽  
Slump Test ◽  
First Approximation ◽  
Empirical Relations ◽  
Shear Yield ◽  
Thickened Tailings

Yield stress values of four thickened (high-density) mineral tailings at varying solids concentrations were determined using three different techniques. The first set of values was measured using the modified slump test approach with an open-ended cylinder having an aspect ratio of 1.2. A second set was derived from measurements obtained from a coaxial cylinder fitted to a Rheolab® MC1 rheometer. The results were graphically compared with those obtained using the miniature vane technique, a popular and well-accepted method of measuring yield stress. Empirical relations developed from the modified slump test appear to predict reasonably accurate yield stress values up to about 200 Pa when compared with the vane and rheometer results. It is concluded that, although the time-dependent nature of the tailings tested may induce errors as much as ±30% for some samples, the modified slump test provides a reliable and simple test for evaluating the yield stress of thickened tailings. The method can therefore be employed as a first approximation of the changing parameters of high-density thickened tailings in the field without necessarily resorting to sophisticated equipment.Key words: high-density thickened tailings, rheology, shear yield stress, slump, torque.

scholarly journals Influence of Humidity on Yield Stress Determination by Slump Test of Slip-Prone Clayey Soils and Their Relation with the Chemical Properties

2012 ◽  
Vol 02 (04) ◽  
pp. 102-105
Author(s):  
Arturo F. Méndez-Sánchez ◽  
Ana M. Paniagua-Mercado ◽  
Karen E. Nieto-Zepeda ◽  
Leonor Pérez-Trejo ◽  
Elvia Diaz Valdés ◽  
...  
Keyword(s):  
Yield Stress ◽  
Chemical Properties ◽  
Clayey Soils ◽  
Stress Determination ◽  
Slump Test

Testing Procedures on Materials to Formulate the Ink for 3D Printing

2020 ◽  
Vol 2674 (2) ◽  
pp. 21-32 ◽  
Author(s):  
Malo Charrier ◽  
Claudiane Ouellet-Plamondon
Keyword(s):  
3D Printing ◽  
Yield Stress ◽  
Three Dimensional ◽  
Testing Procedure ◽  
Full Potential ◽  
Cement Pastes ◽  
Slump Test ◽  
Testing Procedures ◽  
Transportation Sector ◽  
Printing Ink

Three-dimensional (3D) printing has been used in various fields to tackle applications difficult for conventional manufacturing. To realize the full potential of this technology in the transportation sector, it is imperative to identify suitable tests and mixtures for printing “inks” made of mortar. In this study, several conventional and non-conventional tests on mortars and cement pastes were conducted. This work highlights the correlation between the results of slump test and the deformation test that indicates the comportment of the mixture under a stack of printed layers. Moreover, a strong connection between yield stress and mini-slump is observed, demonstrating a simplification of the testing procedure, and a link between the mortar and the cement paste is developed. In the printing ink design phase, this association enables the prediction of flowability. The yield stress and the final radius of the mini-slump tests were very well correlated for the admixture tested. The use of the mini-slump test simplifies the testing procedure and allows for quicker formulations of admixtures in the printing ink.

scholarly journals On the evaluation of yield stress of soils for debris flow analysis

2019 ◽  
Vol 92 ◽  
pp. 05002
Author(s):  
Carlos Besso ◽  
Tácio Mauro Pereira de Campos
Keyword(s):  
Debris Flow ◽  
Yield Stress ◽  
Mass Movement ◽  
Flow Analysis ◽  
Rheological Parameters ◽  
Test Results ◽  
Slump Test ◽  
Acceleration And Deceleration ◽  
Cheap Alternative ◽  
Set Up

Debris flow materials behave as a fluid, hence its analysis requires rheological parameters such as yield stress and viscosity. Yield stress is associated to the start and the end of the mass movement downhill in the sense that it denotes the yield transition from the creep to the flow regime, i.e., passage from solid to fluid state. This paper presents an experimental study of the yield stress of a colluvium from Rio de Janeiro, through its determination in a modified set-up of the slump test and in a rotational parallel plate rheometer. Tests were performed in five different water contents above its liquidity limit, providing a fairly good relationship between yield stress and water content. While slump test provides yield stress related to the beginning of the movement (acceleration), rheometer results are related to flow's outset and stoppage. As a result, the percentual differences between yield stresses associated with acceleration and deceleration were less than 5% in all testes, which is related to the low hysteresis effect in the flow curves obtained in the rotational rheometer. Comparing the two methodologies, it is proposed a correction from rheometer to slump test results. Results obtained are compared with data presented in other studies involving soil's yield stress, showing a good acceptance of the slump test results as a cheap alternative to rheometers.

On the yield stress of geotechnical materials from the slump test

1991 ◽  
Vol 28 (3) ◽  
pp. 457-462 ◽  
Author(s):  
B. Rajani ◽  
N. Morgenstern
Keyword(s):  
Yield Stress ◽  
Undrained Shear Strength ◽  
Bingham Fluid ◽  
Published Data ◽  
Important Class ◽  
Slump Test ◽  
Volcanic Lava ◽  
Undrained Shear ◽  
Good Agreement

There exists an important class of materials, e.g., debris, volcanic lava, sludges, and remoulded sensitive clays, that are known to behave like a Bingham fluid. One of the important properties of a Bingham fluid is the so-called yield stress, and it is usually determined using a coaxial viscometer apparatus. It would be impractical and cumbersome to use this apparatus for many of the materials referred to earlier, and we propose here to examine the use of the slump test. The slump test is used in the concrete industry to evaluate workability and consistency. A statical model is developed to explain the deformation mechanism, and it permits the determination of yield stress. The validity of the statical model is verified using published data on mortar and our own data on Devon silt. The yield stress obtained with the slump test is also compared with the undrained shear strength obtained using the fall cone test. Good agreement is found between the two values. Key words: Bingham fluid, yield stress, slump test, Devon silt.

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