Experimental Research on Rheological Properties of Cemented Mortar in Tail Void Grouting of Shield Tunnel

Grout flow pattern and rheological parameters determine grouting pressure transfer process in annular tail void and filling rate for shield tail void. However, cemented mortar is a mixture of cement, fly ash, sand, bentonite and water, which lead to grout rheological properties and rheological parameters are difficultly determined. Based on orthogonal experimental design method, grout rheological properties were tested by rotational viscometer. Utilizing variance and poly-nonlinear regression analysis, the qualitative and quantitative relationships between mix ratios and rheological parameters were obtained respectively. It is shown that cemented mortar flow pattern commonly agree with Bingham fluid type, and plastic viscosity varies between 1 and 4Pa•s, and shear yield stress varies between 10 to 40Pa respectively. Water-binder ratio and bentonite-water ratio are key influencing factors for grout rheological parameters. With the water-binder ratio increasing and bentonite-water ratio decreasing, plastic viscosity and shear yield stress present reducing tendency.

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Effect of Silica Fume on the Rheological Properties of Cement Paste with Ultra-Low Water Binder Ratio

Materials ◽

10.3390/ma15020554 ◽

2022 ◽

Vol 15 (2) ◽

pp. 554

Author(s):

Juan He ◽

Congmi Cheng ◽

Xiaofen Zhu ◽

Xiaosen Li

Keyword(s):

Hysteresis Loop ◽

Rheological Properties ◽

Yield Stress ◽

Silica Fume ◽

Plastic Viscosity ◽

Rheological Parameters ◽

Loop Area ◽

Binder Ratio ◽

Hysteresis Loop Area ◽

Water Binder Ratio

The effect of silica fume on the rheological properties of a cement–silica fume–high range water reducer–water mixture with ultra-low water binder ratio (CSHWM) was studied. The results indicate that the W/B ratio and silica fume content have different effects on the rheological parameters, including the yield stress, plastic viscosity, and hysteresis loop area. The shear-thickening influence of CSHWM decreased with the increased silica fume content. When the silica fume content increased from 0% to 35%, the mixture with W/B ratio of 0.19 and 0.23 changed from a dilatant fluid to a Newtonian fluid, and then to a pseudoplastic fluid. When the silica fume content was less than 15%, the yield stress was close to 0. With the increase of silica fume content, the yield stress increased rapidly. The plastic viscosity and hysteresis loop area decreased slightly with the addition of a small amount of silica fume, but increased significantly with the continuous increase of silica fume. Compared with the Bingham and modified Bingham models, the Herschel–Buckley model is more applicable for this CSHWM.

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Influence of Ground Slag on the Rheology of Mortar

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.438-439.67 ◽

2013 ◽

Vol 438-439 ◽

pp. 67-71

Author(s):

Qian Qian Zhang ◽

Jian Zhong Liu ◽

Jia Ping Liu

Keyword(s):

Film Thickness ◽

Specific Surface ◽

Yield Stress ◽

Surface Area ◽

Specific Surface Area ◽

Water Film ◽

Plastic Viscosity ◽

Rheological Parameters ◽

Water Film Thickness ◽

Binder Ratio

The effects of ground slag with different specific surface area on the rheology of mortar at water-binder ratio of 0.25, 0.28 and 0.30 were investigated, and the combined effects of packing density and solid surface area on the rheology of mortar were evaluated in terms of the water film thickness. The results show that with the increasing of specific surface area of slag (220 m2/kg-784 m2/kg), plastic viscosity and yield stress decrease. The correlations of yield stress and plastic viscosity to the water film thickness are basically linear with high correlation R2 values. The action of the ground slag on the rheology of mortar can be characterized by water film thickness, and with the increasing of water film thickness the rheological parameters decrease.

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Evolution of flow properties, plastic viscosity, and yield stress of alkali-activated fly ash/slag pastes

RILEM Technical Letters ◽

10.21809/rilemtechlett.2020.123 ◽

2020 ◽

Vol 5 ◽

pp. 141-149

Author(s):

Mohammed Fouad Alnahhal ◽

Taehwan Kim ◽

Ailar Hajimohammadi

Keyword(s):

Fly Ash ◽

Yield Stress ◽

Plastic Viscosity ◽

Rheological Parameters ◽

Time Intervals ◽

Increasing Trend ◽

Binder Ratio ◽

Drastic Effect ◽

Effect On Yield ◽

Alkali Activated

The development of cementless concrete is attracting increasing attention in practice and research to reduce both greenhouse gas emissions and energy consumption of concrete. Alkali-activated materials (AAMs) are one of the viable alternatives to replace Portland cement due to their lower CO2 emissions. This study investigated the evolution of rheological parameters of alkali-activated fly ash/slag pastes as a function of time. Flowability and rheological measurements were carried out to determine the fluidity, plastic viscosity, and yield stress at different time intervals. The effects of the slag content, the concentration of SiO2 in the activator, and the solution/binder ratio were considered. Based on the results, the yield stress and plastic viscosity followed an increasing trend over time coinciding with a reduction in the paste fluidity. The plastic viscosity of AAM pastes was in the range of 1.3–9.5 Pa.s and 2.6–28.9 Pa.s after 5 min and 45 min of mixing, respectively. Given the same alkali activator, the higher content of slag the paste had, the higher yield stress the paste showed. In addition, this paper confirmed that the SiO2/Na2O ratio in the activator had no significant effect on yield stress, but a drastic effect of this ratio was found on the plastic viscosity of the paste.

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The shear and compressive yield stress of fibrillated acacia pulp fiber suspensions

Nordic Pulp & Paper Research Journal ◽

10.1515/npprj-2019-0065 ◽

2020 ◽

Vol 35 (2) ◽

pp. 243-250

Author(s):

Jiulong Sha ◽

Yueyue Yang ◽

Can Wang ◽

Wei Li ◽

Peng Lu ◽

...

Keyword(s):

Yield Stress ◽

Paper Industry ◽

Pulp Fiber ◽

Fiber Suspensions ◽

Fiber Morphology ◽

Shear Yield Stress ◽

Geometrical Properties ◽

Compressive Yield Stress ◽

Shear Yield ◽

Fiber Cell Wall

AbstractThe degree of interactions between fibers and the tendency of fibers to form flocs play an important role in effective unit operation in pulp and paper industry. Mechanical treatments may damage the structure of the fiber cell wall and geometrical properties, and ultimately change the fiber-fiber interactions. In this study, the gel crowding number, compressive and shear yield stress of fibrillated acacia pulps were investigated, and the results showed that the gel crowding number of the refined pulp samples ranged from 8.7 to 10.7, which were much lower than that of un-refined pulps. As the concentration increased, both the compressive yield stress {P_{y}} and shear yield stress {\tau _{y}} of all suspensions increased accordingly, and the yield stress was found to depend on a power law of the crowding number. Moreover, the values of {\tau _{y}}/{P_{y}} were also examined and the variation of {\tau _{y}}/{P_{y}} became largely dependent on the fiber morphology and mass concentration.

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Shear yield stress of partially flocculated colloidal suspensions

AIChE Journal ◽

10.1002/aic.690440305 ◽

1998 ◽

Vol 44 (3) ◽

pp. 538-544 ◽

Cited By ~ 137

Author(s):

Peter J. Scales ◽

Stephen B. Johnson ◽

Thomas W. Healy ◽

Prakash C. Kapur

Keyword(s):

Yield Stress ◽

Colloidal Suspensions ◽

Shear Yield Stress ◽

Shear Yield

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Demonstration of Combined Shear and Squeeze Strengthening Modes in a Searle-Type Magnetorheometer

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation and Control of Adaptive Systems; Integrated System Design and Implementation ◽

10.1115/smasis2013-3244 ◽

2013 ◽

Cited By ~ 6

Author(s):

Andrew C. Becnel ◽

Norman M. Wereley

Keyword(s):

Yield Stress ◽

Energy Absorption ◽

Shear Yield Stress ◽

Particle Chain ◽

Solids Loading ◽

Mr Fluids ◽

Shear Yield ◽

Microstructure Model ◽

Novel Method ◽

A Chain

This research details a novel method of increasing the shear yield stress of magnetorheological (MR) fluids by combining shear and squeeze modes of operation to manipulate particle chain structures, to achieve so-called compression-assisted aggregation. The contribution of both active gap separation and particle concentration are experimentally measured using a custom-built Searle cell magnetorheometer, which is a model device emulating a rotary Magnetorheological Energy Absorber (MREA). Characterization data from large (1 mm) and small (250 μm) gap geometries are compared to investigate the effect of the gap on yield stress by compression enhancement. Two MR fluids having different particle concentrations (32 vol% and 40 vol%) are also characterized to demonstrate the effect of solids loading on compression-assisted chain aggregation. Details of the experimental setup and method are presented, and a chain microstructure model is used to explain experimental trends. The torque resisted by practical rotary MREAs is directly related to the strength of the MR fluid used, as measured by the shear yield stress. This study demonstrates that it is feasible, utilizing the compression-enhanced shear yield stress, to either (1) design a rotary MREA of a given volume to achieve higher energy absorption density (energy absorbed normalize by device volume), or (2) reduce the volume of a given rotary MREA to achieve the same energy absorption density.

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Design of portable rheometer with new vane geometry to estimate concrete rheological parameters

Journal of Civil Engineering and Management ◽

10.3846/13923730.2015.1128481 ◽

2016 ◽

Vol 23 (3) ◽

pp. 347-355 ◽

Cited By ~ 8

Author(s):

Hamza SOUALHI ◽

El-Hadj KADRI ◽

Tien-Tung NGO ◽

Adrien BOUVET ◽

François CUSSIGH ◽

...

Keyword(s):

Yield Stress ◽

Coefficient Of Variation ◽

Test Procedure ◽

Plastic Viscosity ◽

Rheological Parameters ◽

Construction Site ◽

Wide Range ◽

Mineral Additions ◽

High Plastic ◽

Rheometer Test

This paper presents the development of a portable vane rheometer to estimate concrete plastic viscosity and yield stress. The apparatus can be used not only in laboratory but also on construction site. In this study, new blade geometry was proposed to minimize the effect of segregation of concrete during testing, and also to expand the wide range of concrete workability with a slump of approximately from 7 cm to fluid concrete, and concrete with high plastic viscosity such as concrete with mineral additions. The used blade (U shaped and reversed) allows reducing the vibration of the apparatus, and obtaining more stable measurements. The obtained results permit validating the rheometer test procedure and confirmed that the results are reliable, with a low coefficient of variation of 9% for repetitive test and of 5.8% for reproductive tests.

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