scholarly journals Non-Newtonian Behaviors of Crumb Rubber-Modified Bituminous Binders

2018 ◽  
Vol 8 (10) ◽  
pp. 1760 ◽  
Author(s):  
Haopeng Wang ◽  
Xueyan Liu ◽  
Panos Apostolidis ◽  
Tom Scarpas
Keyword(s):  
Shear Thinning ◽  
Crumb Rubber ◽  
Shear Loading ◽  
Modified Bitumen ◽  
Zero Shear Viscosity ◽  
Shear Rates ◽  
Rate Dependent ◽  
Correlation Degree ◽  
Warm Mix Additives ◽  
Bituminous Binders

Crumb rubber-modified bitumen (CRMB) has been utilized in the asphalt paving industry for decades due to its various benefits. The complex interaction between bitumen and crumb rubber as well as the addition of warm-mix additives makes the typical laws of Newtonian fluids insufficient to describe the behaviors of highly modified bituminous binders. To systematically explore the non-Newtonian behaviors of CRMB, a dynamic shear rheometer was utilized to apply shear loading on the samples at various temperatures and shear rates. Results show that the viscosity of different binders are highly temperature- and shear rate-dependent, while highly modified binders exhibit more obvious shear-thinning behaviors at certain temperatures. With the help of zero shear viscosity and yield stress, the shear-thinning behaviors of non-Newtonian binders can be sufficiently characterized. The Arrhenius equation is invalid to describe viscosity-temperature characteristics of bitumen in the non-Newtonian region. A second-order polynomial function was proposed to characterize the viscosity-temperature dependence with a high correlation degree.

scholarly journals Fatigue performance of long-term aged crumb rubber modified bitumen containing warm-mix additives

2020 ◽  
Vol 239 ◽  
pp. 117824 ◽  
Author(s):  
Haopeng Wang ◽  
Xueyan Liu ◽  
Martin van de Ven ◽  
Guoyang Lu ◽  
Sandra Erkens ◽  
...  
Keyword(s):  
Crumb Rubber ◽  
Fatigue Performance ◽  
Modified Bitumen ◽  
Warm Mix Additives

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.

Experimental and theoretical investigations on the viscosity of heterogeneous asphalt binders

2017 ◽  
Vol 50 (4) ◽  
pp. 354-371 ◽  
Author(s):  
Aboelkasim Diab
Keyword(s):  
Flow Behavior ◽  
Ethylene Vinyl Acetate ◽  
Hydrated Lime ◽  
Crumb Rubber ◽  
Asphalt Binders ◽  
Zero Shear Viscosity ◽  
Shear Rates ◽  
Wide Range ◽  
Theoretical Investigations ◽  
Pavement Construction

The inherent multiphase structure of heterogeneous asphalt binders (additives containing binders) may complicate viscosity understanding and predictions in the Newtonian or non-Newtonian response. The objective of this article is to understand the viscosity characteristics of heterogeneous asphalt binders based on experimental and theoretical investigations over a wide range of conditions the matter may encounter in the field (temperatures and oxidative aging). Selected materials representing the generic additives commonly used for pavement construction including styrene–butadiene–styrene block copolymer and ethylene–vinyl acetate copolymer, crumb rubber, and two mineral fillers, namely hydrated lime and fly ash, were utilized separately at different concentrations to produce the heterogeneous materials under study. The effects of varied temperatures as well as short- and long-term aging processes were studied for the materials over a wide range of shear rates. A further theoretical investigation was carried out by addressing the capability of Tscheuschner model to predict the flow behavior under the aforementioned conditions. In addition, the zero shear viscosity said to be an intrinsic characteristic of asphalt binders was evaluated using the regression analysis of data predicted from Tscheuschner model. Overall, the shear thinning behavior of heterogeneous asphalt binders occurred at low shear rates as compared to the base binder, especially at low temperatures. Emphasis was placed on the repeatability of the model predictions under different conditions, which could be an initiative to provide a simple but accurate representation of the viscosity of heterogeneous asphalt binders.

Adenosine Diphosphate-Induced Aggregation of Human Platelets in Flow Through Tubes: III. Shear and Extrinsic Fibrinogen-Dependent Effects

1994 ◽  
Vol 71 (01) ◽  
pp. 078-090 ◽  
Author(s):  
H L Goldsmith ◽  
M M Frojmovic ◽  
Susan Braovac ◽  
Fiona McIntosh ◽  
T Wong
Keyword(s):  
Shear Rate ◽  
Single Cells ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
Size Analysis ◽  
Fibrinogen Concentration ◽  
Human Fibrinogen ◽  
Shear Rates ◽  
Rate Dependent ◽  
Induced Aggregation

SummaryThe effect of shear rate and fibrinogen concentration on adenosine diphosphate-induced aggregation of suspensions of washed human platelets in Poiseuille flow at 23°C was studied using a previously described double infusion technique and resistive particle counter size analysis (1). Using suspensions of multiple-centrifuged and -washed cells in Tyrodes-albumin [3 × 105 μl−1; (17)] with [fibrinogen] from 0 to 1.2μM, the, rate and extent of aggregation with 0.7 μM ADP in Tyrodes-albumin were measured over a range of mean transit times from 0.2 to 43 s, and at mean tube shear rates, Ḡ, = 41.9, 335 and 1,335 s−1. As measured by the decrease in singlet concentration, aggregation at 1.2 μM fibrinogen increased with increasing Ḡ up to 1,335 s1, in contrast to that previously reported in citratcd plasma, in which aggregation reached a maximum at Ḡ = 335 s−1. Without added fibrinogen, there was no aggregation at Ḡ = 41.9 s1; at Ḡ = 335 s1, there was significant aggregation but with an initial lag time, aggregation increasing further at Ḡ = 1,335 s−1. Without added fibrinogen, aggregation was abolished at all Ḡ upon incubation with the hexapeptide GRGDSP, but was almost unaffected by addition of an F(ab’)2 fragment of an antibody to human fibrinogen. Aggregation in the absence of added fibrinogen was also observed at 37°C. The activation of the multiple-washed platelets was tested using flow cytometry with the fluorescently labelled monoclonal antibodies FITC-PAC1 and FITC-9F9. It was shown that 57% of single cells in unactivated PRT expressed maximal GPIIb-IIIa fibrinogen receptors (MoAb PAC1) and 54% expressed pre-bound fibrinogen (MoAb 9F9), with further increases on ADP activation. However, incubation with GRGDSP and the F(ab’)2 fragment did not inhibit the prebound fibrinogen. Moreover, relatively unactivated cells (8% expressing receptor, 14% prebound fibrinogen), prepared from acidified cPRP by single centrifugation with 50 nM of the stable prostacyclin derivative, ZK 36 374, and resuspension in Tyrodes-albumin at 5 × 104 μl−1, aggregated with 2 and 5 μM ADP at Ḡ = 335 and 1,335 s−1 in the absence of added fibrinogen. We therefore postulate that a protein such as von Willebrand factor, secreted during platelet isolation or in flow at sufficiently high shear rates, may yield the observed shear-rate dependent aggregation without fibrinogen.

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