A revised relationship between molecular weight and reduced angular frequency in δ-method applied to unmodified petroleum bitumens

Cuciniello, Giacomo; Filippi, Sara; Cappello, Miriam; Leandri, Pietro; Polacco, Giovanni

doi:10.1080/14680629.2020.1828153

Cited by 4 publications

(13 citation statements)

References 22 publications

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“…The dynamic material functions of asphalt U were investigated using a DSR‐Anton Paar MCR301 9 . Group B of asphalt blends was tested in ARES–G2 rheometer of TA 3 .…”

Section: Methodsmentioning

confidence: 99%

“…Such materials have a “memory” in that they can “remember” deformations occurring from time −∞ up to the present observation time, t. Since ω ~ 1/t, G*(ω) should be known on interval frequencies that are as wide as possible. Fortunately, this is not a grave constraint because many materials belong to the set of rheologically simple materials 3,7,9 in which time–temperature superposition (tTs) can be used 7,8 . The complex modulus, G*(ω), is given in two forms 10 :

Polar form : normalG * ((), ω) = (||, normalG * ((), ω)) \exp ([], normali δ ((), ω)), normali = \sqrt{- 1},

where δ(ω) represents the phase shift between the shear stress and the shear strain, or

Cartesian form : normalG * ((), ω) = G^{'} ((), ω) + normali G^{″} ((), ω),

where the storage modulus G'(ω) is related to the average energy stored and released per cycle and the loss modulus G"(ω) is related to dissipation in a complete cycle.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, Cuciniello et al 9 ,27 compared the phase angle method discussed by Tuminello, 14 to the GPC results for conventional asphalts. In these cases, master curves of phase angle were constructed and then used to calculate the molecular weight distribution (MWD).…”

Section: Introductionmentioning

confidence: 99%

“…One of the crucial elements in this procedure is the calibration equation. This equation relates the molecular weight of asphalt to the reduced angular frequency,

\overset{ω}{true}

, which is the independent variable of the dynamic master curves 6,9,13,16 …”

Section: Introductionmentioning

confidence: 99%

“…The reduced frequency was transformed into the molecular weight via the power law relation

normalM = normalK {(\overset{ω}{true})}^{- α},

where M represents the molecular weight and K and α are model parameters 6,9,10,16 …”

Section: Introductionmentioning

confidence: 99%

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Development of internal structure of polymer‐modified asphalts via transformations of the reduced frequency

Jasso

Stastna

Polacco

et al. 2020

J of Applied Polymer Sci

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The independent variable of dynamic material functions and corresponding master curves, the reduced angular frequency ω , was transformed into the apparent molecular weight MW*. As a function of MW*, the normalized master phase angle represented an apparent cumulative molecular weight. This function's numerical differentiation yielded the probability density function of the apparent molecular weight, f(MW*). While this procedure is unproblematic in conventional (straight run) asphalts, it is yielding peaks of negative MW* in polymer modified asphalts. Thus reduced frequency was also transformed to the temperature, which allowed us to determine that the apparent glass transition temperature as the maximum on the master curve of loss modulus G"(T). The master curve of the normalized phase angle as a function of temperature helped to explain the phenomenon associated with the probability density function in modified asphalts. The results presented in this article were obtained numerically, without the use of rheological models.

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“…The dynamic material functions of asphalt U were investigated using a DSR‐Anton Paar MCR301 9 . Group B of asphalt blends was tested in ARES–G2 rheometer of TA 3 .…”

Section: Methodsmentioning

confidence: 99%

Polar form : normalG * ((), ω) = (||, normalG * ((), ω)) \exp ([], normali δ ((), ω)), normali = \sqrt{- 1},

where δ(ω) represents the phase shift between the shear stress and the shear strain, or

Cartesian form : normalG * ((), ω) = G^{'} ((), ω) + normali G^{″} ((), ω),

where the storage modulus G'(ω) is related to the average energy stored and released per cycle and the loss modulus G"(ω) is related to dissipation in a complete cycle.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…One of the crucial elements in this procedure is the calibration equation. This equation relates the molecular weight of asphalt to the reduced angular frequency,

\overset{ω}{true}

, which is the independent variable of the dynamic master curves 6,9,13,16 …”

Section: Introductionmentioning

confidence: 99%

“…The reduced frequency was transformed into the molecular weight via the power law relation

normalM = normalK {(\overset{ω}{true})}^{- α},

where M represents the molecular weight and K and α are model parameters 6,9,10,16 …”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Development of internal structure of polymer‐modified asphalts via transformations of the reduced frequency

Jasso

Stastna

Polacco

et al. 2020

J of Applied Polymer Sci

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Apparent Molecular Weight Distributions for Investigating Aging in Polymer-Modified Bitumen

Cappello

Filippi

Hung

et al. 2021

Advances in Polymer Technology

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The oxidative aging of bituminous binders affects the performance and durability of pavements. In the case of polymer-modified binders, aging involves both bitumen and polymers and has a strong impact on the whole architecture of the material. Rheology may help in understanding these structural changes, and interesting information may be obtained by analysing the evolution of apparent molecular weight distributions. This was demonstrated with a bituminous binder modified with a poly(styrene-butadiene) block copolymer and subjected to prolonged artificial aging. Isothermal frequency sweep tests were used to construct master curves of the phase angle and magnitude of the complex modulus. The master curves were then used to calculate relaxation spectra and apparent molecular weight distributions of the binders, as well as simulated temperature sweep tests. A comparison of the behaviour of the base and modified bitumen highlighted the role of the polymer in aging. Polymer degradation significantly damages the elastomeric network, yet the residual polymer chains still interact with the bitumen molecules and reduce their oxidative aging. The apparent molecular weight distributions were deconvoluted to create an aging index specifically developed for polymer-modified bitumen.

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A Literature Review of Bitumen Aging: From Laboratory Procedures to Field Evaluation

Siroma

Nguyen

Huard

et al. 2022

Journal of Testing and Evaluation

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Because bitumen aging is behind the major pavement distresses, a better understanding of it is of utmost importance for tailoring longer-lasting roads and developing more effective maintenance strategies. For this purpose, this paper presents an in-depth review of the relevant literature on the aging phenomenon of neat (unmodified) bitumen. The main accelerated laboratory aging procedures as well as some recent ones, for both bitumen and asphalt mix, are presented, and their effectiveness in reproducing the effects corresponding to field aging are discussed. Then, the main laboratory tests used to track the evolution of bitumen aging and some end-of-life criteria that reflect poor pavement performance are outlined. Finally, a promising method whereby the colloidal structure of bitumen can be estimated from its rheological behavior is presented.

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A revised relationship between molecular weight and reduced angular frequency in δ-method applied to unmodified petroleum bitumens

Cited by 4 publications

References 22 publications

Development of internal structure of polymer‐modified asphalts via transformations of the reduced frequency

Development of internal structure of polymer‐modified asphalts via transformations of the reduced frequency

Apparent Molecular Weight Distributions for Investigating Aging in Polymer-Modified Bitumen

A Literature Review of Bitumen Aging: From Laboratory Procedures to Field Evaluation

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