Microstructure Model and Rheological Model of Fresh Cement Pastes

A Rheological Model of Semisolid Magnesium Alloy Slurries

Materials Science Forum ◽

10.4028/www.scientific.net/msf.488-489.333 ◽

2005 ◽

Vol 488-489 ◽

pp. 333-336 ◽

Cited By ~ 1

Author(s):

L. Li ◽

X.W. Zhou ◽

J.Y. Chen

Keyword(s):

Magnesium Alloy ◽

Shear Rate ◽

Rheological Properties ◽

Apparent Viscosity ◽

Rheological Model ◽

The State ◽

Simple Shearing ◽

Flow Conditions ◽

Rheological Behaviors ◽

Microstructure Model

In this paper a rheological model is presented which describes the rheological behaviors of liquid-like semisolid magnesium alloy under a simple shearing flow. On the basis of Chen and Fan’s mono-dispersion microstructure model of semisolid metal slurry, the particle size distribution is considered in this model. It is believed that it is the state of agglomeration which determines the rheological behaviors of the slurry, whereas the external flow conditions such as shear rate and shearing time, affect the rheological properties by changing the state of agglomeration. The expressions of collision rate between two agglomerates, effective solid fraction and the formula of apparent viscosity of Chen and Fan’s model are corrected according to the experimental results and statistical mechanics. Finally calculated apparent viscosity and the average number of the particles of AZ91D by the developed model as functions of shear rate are presented. These results show that there is a one to one coupling between the rheological properties of the magnesium alloy slurries and the state of the agglomeration.

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Test protocol and rheological model influence on determining the rheological properties of cement pastes

Journal of Building Engineering ◽

10.1016/j.jobe.2021.103206 ◽

2021 ◽

pp. 103206

Author(s):

R.S. Campos ◽

G.F. Maciel

Keyword(s):

Rheological Properties ◽

Rheological Model ◽

Test Protocol ◽

Cement Pastes

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THE INFLUENCE OF CALCIUM NITRATE ON THE PLASTICIZING EFFECT OF CEMENT PASTE

Journal of Civil Engineering and Management ◽

10.3846/13923730.2015.1120771 ◽

2016 ◽

Vol 22 (3) ◽

pp. 434-441 ◽

Cited By ~ 5

Author(s):

Gintautas SKRIPKIŪNAS ◽

Asta KIČAITĖ ◽

Mindaugas MACIJAUSKAS

Keyword(s):

Rheological Properties ◽

Cement Paste ◽

Rheological Model ◽

Rotation Speed ◽

Calcium Nitrate ◽

Flow Curves ◽

Rotational Viscometer ◽

Cement Pastes ◽

Steady Rotation

The rheological properties of the cement pastes have been determined using a rotational viscometer under a special testing routine by increasing and retaining a steady rotation speed of the viscometer cylinder up to certain values and for a certain time. These tests, using rotational viscometer, have been conducted by making the assessment of cement paste flow curves, using Bingham rheological model. Rheological properties of cement pastes were tested at different times after pastes mixing: 0 min, 30 min, 60 min, 90 min, 120 min and 180 min. Cement pastes with same W/C ratio equal to 0.35 were tested. The content of admixture was used 0%, 0.5%, 1%, 2%, 3% and 5%. The admixture of Ca(NO3)2 can be used in cement pastes and concretes without a reduction in consistency during 120 min in the dosage of up to 2%. Dosages of Ca(NO3)2 from 3% are not recommended for cement pastes and concrete, they significantly increase the viscosity of mixtures immediately after mixing The admixture of calcium nitrate changes thixotropy of cement pastes. In this case, a bigger dosage of calcium nitrate increases the thixotropy of pastes.

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