Zero-Shear Viscosity of Bituminous Binder and Its Relation to Bituminous Mixture's Rutting Resistance

1996 ◽  
Vol 1535 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Dariusz Sybilski
Keyword(s):  
Shear Viscosity ◽  
Close Correlation ◽  
Equation Modeling ◽  
Zero Shear Viscosity ◽  
Rotational Viscometer ◽  
Cross Model ◽  
Rutting Resistance ◽  
Before And After ◽  
Bituminous Binders ◽  
Newtonian Behavior

When testing viscosity of polymer-bitumen systems a question arises about interpretation of results as those systems behave as non-Newtonian liquids. A simple equation modeling non-Newtonian behavior of polymer-bitumens was proposed (which is a simplified version of the CROSS model). The equation used enables the calculation of zero-shear viscosity η0 from viscosity measurements conducted under various shear conditions, that is, with rotational viscometer at different shear rates (stresses). Test results are presented of several polymer-modified bituminous binders before and after Thin film oven test aging and discussion of non-Newtonian behavior. The wheel tracking test (Laboratoric Central des Ponts et Chaussées) was conducted for asphalt concrete with several bituminous binders, either plain bitumens or polymer modified. To estimate bituminous mixture's rutting resistance, a new relationship has been proposed to calculate N10 (wheel passes number to rut depth 10 mm). Close correlation was found between N10 and zero-shear (or absolute) viscosity of binders at 60°C, both conventional and polymer modified.

USING STEADY SHEAR RATE SWEEP PROTOCOL TO DETERMINE ZERO SHEAR VISCOSITY OF UNAGED AND AGED UNMODIFIED BITUMINOUS BINDERS

2021 ◽  
Author(s):  
Syed Mubashirhussain ◽  
Venkaiah Chowdary
Keyword(s):  
Shear Rate ◽  
Shear Viscosity ◽  
Steady Shear ◽  
Zero Shear Viscosity ◽  
Shear Rates ◽  
Bituminous Mixtures ◽  
Bituminous Binders ◽  
Bituminous Pavements ◽  
Low Shear

Rutting is one of the most significant distresses occurring in bituminous pavements at higher pavement temperatures. Researchers have been focusing on developing bitumen binder parameters that can be used to predict the rutting resistance of bituminous mixtures and Zero Shear Viscosity (ZSV) has proven its efficacy as a binder rutting parameter. A stepwise steady shear rate sweep test with two cycles of forward and backward sweeps was conducted at very low shear rates to determine the ZSV of unaged, short-term aged, and long-term aged unmodified bitumen binders. A convergence of the steady-state viscosities was observed at different shear rates in the first forward sweep. The response of the binders was independent of shear rate, time and the effect of shear history was negligible. As the shear rates correspond to the ZSV regime, ZSV was determined from the first forward sweep. The ZSV correlated well with the three existing rutting parameters.

Zero Shear Viscosity of Asphalt Binders

2002 ◽  
Vol 1810 (1) ◽  
pp. 54-62 ◽  
Author(s):  
David A. Anderson ◽  
Yann M. Le Hir ◽  
Jean-Pascal Planche ◽  
Didier Martin ◽  
Aroon Shenoy
Keyword(s):  
Shear Viscosity ◽  
Alternative Methods ◽  
Asphalt Binders ◽  
Polymer Modification ◽  
Creep Tests ◽  
Zero Shear Viscosity ◽  
Dynamic Data ◽  
Cross Model ◽  
Dynamic Experiments ◽  
Term Creep

Recently there has been considerable interest, especially in Europe, in the use of zero shear viscosity (ZSV) as a specification criterion for asphalt binders. This interest is precipitated by the apparent inability of the current Superpave® criterion, G*/sin(δ), to capture the contribution to rutting resistance afforded by polymer modification. ZSV can be determined directly from long-term creep tests, but such tests are timeconsuming and are often very difficult to perform. Several alternative methods for determining the ZSV have been proposed in the literature, including extrapolating the dynamic viscosity to zero frequency; applying the Cross model to dynamic data; and superimposing multiple short-term, non-steady-state creep tests. A number of methods for determining the ZSV from both creep and dynamic data were evaluated. Laboratory test data for 10 unmodified and modified binders were obtained through a series of creep and dynamic experiments. ZSV values obtained from two of the more promising methods were compared, along with a comparison of the ZSV ranking with the Superpave grading temperature. Two of the methods provided very similar values for the ZSV when applied over a considerable range in test temperature, and the results from the two methods could be used interchangeably for the materials that were tested. The binders ranked quite differently when ranked according to their Superpave grading temperature or their ZSV.

Viscosity of Some Contemporary Contrast Media before and after Mixing with Whole Blood

1992 ◽  
Vol 33 (6) ◽  
pp. 600-605 ◽  
Author(s):  
Ö. Smedby
Keyword(s):  
Contrast Media ◽  
Shear Viscosity ◽  
Whole Blood ◽  
Blood Rheology ◽  
Rotational Viscometer ◽  
Shear Rates ◽  
Before And After ◽  
Low Shear Viscosity ◽  
Contrast Medium Concentration ◽  
Low Shear

The viscosity of 7 contrast media was measured using a rotational viscometer. When solutions with similar iodine concentrations were compared, the highest viscosities were found for the nonionic dimers iodixanol and iotrolan, the lowest for diatrizoate, iopamidol, and iopromide, and intermediate values for iohexol and ioxaglate. The viscosity of iohexol and ioxaglate was found to vary linearly with temperature and quadratically with concentration. Whole-blood viscosity was measured for 5 subjects at high and low shear rates before and after mixing with contrast media in various proportions. Low-shear viscosity was found to decrease and high-shear viscosity to increase with contrast medium concentration. It is concluded that the contrast media currently used may affect blood rheology less than previous agents, despite their higher viscosity.

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