Nonlinear rheological behavior of bitumen under LAOS stress

Shan, Liyan; He, Hongsen; Wagner, Norman J.; Zhuang, Łi

doi:10.1122/1.5018516

Cited by 26 publications

(4 citation statements)

References 50 publications

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“…It can also be argued that such strain localization weakens the nonlinear behavior of these gels, for example, strain-stiffening responses, which are prominent in acrylic gels. , For acrylic gels, these strain-stiffening responses were related to the maximum extensibility of midblocks before being pulled out from the aggregates. We have not observed any clear sign of nonlinearity from the rheological responses of the gels investigated here, i.e., the e 3 and ν 3 values are almost zero. − It may be possible that because of local inhomogeneity, individual PI-block may have reached the maximum stretchability but collectively not displaying the strain-stiffening response. Also, a weaker association of PS-blocks in comparison to that of the PMMA block in acrylic gels cannot be ruled out.…”

Section: Resultsmentioning

confidence: 70%

Capturing the Transient Microstructure of a Physically Assembled Gel Subjected to Temperature and Large Deformation

et al. 2021

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The microstructure of physically assembled gels depends on mechanical loading and environmental stimuli such as temperature. Here, we report the real-time change in the structure of physically assembled triblock copolymer gels that consist of 10 and 20 wt % of poly(styrene)–poly(isoprene)–poly(styrene) [PS–PI–PS] triblock copolymer in mineral oil (i) during the gelation process with decreasing temperature, (ii) subjected to large oscillatory deformation, and (iii) during the stress-relaxation process after the application of a step strain. The presence of loosely bounded PS aggregates at temperatures higher than the rheologically determined gelation temperature (T gel) signifies the progressive gelation process spanning over a broad temperature range. However, the microstructure fully develops at temperatures sufficiently lower than T gel. The microstructure orients in the stretching direction with the applied strain. In an oscillation strain cycle, such oriented structure has been observed at low strain. However, at large strain, the oriented structure splits because of strain localization suggesting that only a fraction of PI blocks participates in load bearing. Both microstructure recovery and time-dependent moduli during the stress-relaxation process after the application of a step strain have been captured using a stretched-exponential model. However, the microstructure recovery time has been found to be 2 orders of magnitude slower than the stress-relaxation time at room temperature, indicating a complex nature of stress relaxation and microstructure recovery processes involving midblock relaxation, endblock pullout, and reassociation. Due to their viscoelastic nature, these gels’ mechanical responses are sensitive to strain, temperature, and rate of deformation. Therefore, insights into the microstructural change as a function of these parameters will assist these gels’ real-life applications and design new gels with improved properties.

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Section: Resultsmentioning

confidence: 70%

Capturing the Transient Microstructure of a Physically Assembled Gel Subjected to Temperature and Large Deformation

et al. 2021

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“…The tests followed the protocols developed in the previous study. [19] Two replicates were performed for each test in this paper.…”

Section: Methodsmentioning

confidence: 99%

Creep Damage Evolution Process of Asphalt Binder Based On Viscoelastic Characteristics

Tian

Shan

et al. 2021

Preprint

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The creep damage evolution of asphalt binder plays a significant role in investigating the formation mechanism of rutting, a common type of distress at high temperature for asphalt pavements. However, the reliability of existing creep damage parameters is under questioned, and these parameters cannot accurately illustrate change law of intrinsic microstructure about asphalt binder. In this paper, a new testing protocol is given access to study the evolution of viscoelastic parameters during creep damage. It is completed by inserting the frequency sweep during creep test. The frequency sweep curve clusters are fitted using the generalized Kelvin-Voigt model for obtaining the change law of model parameters. Based on the change law and sensitivity analysis of model parameters, (E2 + E3)/2 is proposed as the creep damage variable. According to the curve of (E2+E3)/2 versus loading time, two stages during the creep test can be identified: an approximate constant value in phase Ⅰ and a linear decrease in phase Ⅱ. Intrinsic differences about creep property of binders can be determined by this new proposed parameter. Above results not only ensure better understanding of the creep damage mechanism of binders, but also lay the theoretical foundation on predicting the anti-rutting performance of binders.

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“…In recent decades, the application of modified bitumens has experienced tremendous growth. There are numerous modifiers available, and the Styrene-Butadiene-Styrene (SBS) polymer is among one of the most used ones [2]. SBS polymer can form a three-dimensional rubbery network within the bitumen, which significantly benefits pavement performance [3].…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study for Creep and Recovery Behavior Characterization of Modified Bitumens Using the MSCR Test

et al. 2023

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In recent decades, the application of modified bitumens has experienced tremendous growth. However, due to the varying modification mechanism of different modifiers, the creep and recovery properties of modified bitumen have not been comprehensively understood. This study aims to evaluate the creep and recovery properties of several representative modified bitumens using the multi-stress creep recovery (MSCR) test. The MSCR test can highlight the unique delayed elasticity of modified bitumen and it uses a high stress level, which is more comparable to the field. In particular, this test also aims to identify the effects of different aging conditions. To do so, a total of 15 bitumens, including 7 elastomeric-modified bitumens, 5 non-elastomeric-modified bitumens, and 3 plain bitumens, were prepared and examined. Furthermore, 10 different aging conditions were considered. The results suggest that the generation mechanism of elasticity varies for different modified bitumens. There are two types of elasticities, which are energy elasticity and entropy elasticity, and their differences need more attention in the road bitumen material community. Aging changes the percentages of contributions from energy elasticity and entropy elasticity to the bitumen’s overall recovery performance. The increase in “bad” energy elasticity may compensate for part of the “good” entropy elasticity loss, but overall, the bitumen’s recovery rate is decreasing and the ratio of energy elasticity is increasing, which might hinder the bitumen’s road performance.

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Nonlinear rheological behavior of bitumen under LAOS stress

Cited by 26 publications

References 50 publications

Capturing the Transient Microstructure of a Physically Assembled Gel Subjected to Temperature and Large Deformation

Capturing the Transient Microstructure of a Physically Assembled Gel Subjected to Temperature and Large Deformation

Creep Damage Evolution Process of Asphalt Binder Based On Viscoelastic Characteristics

A Comparative Study for Creep and Recovery Behavior Characterization of Modified Bitumens Using the MSCR Test

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