Molecular dynamics study on the glass forming process of asphalt

Kang, Yang; Zhou, Danhong; Wu, Qiang; Liang, Rui; Shangguan, Shaoxin; Liao, Zhiwei; Wei, Ning

doi:10.1016/j.conbuildmat.2019.04.138

Cited by 64 publications

(17 citation statements)

References 30 publications

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“…The fractional free volume (FFV) is the ratio of the free volume to the total volume of the molecular system, which can be calculated from Equation (5). The smaller the FFV of the asphalt, the less mobile and less permeable are the molecules in the system [ 39 ]. Macroscopically, this is reflected in the hardening of the asphalt and its increased resistance to deformation.…”

Section: Resultsmentioning

confidence: 99%

Multi-Scale Characterization of High-Temperature Properties and Thermal Storage Stability Performance of Discarded-Mask-Modified Asphalt

Hui

Yang

et al. 2022

Materials

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In the context of the global pandemic of COVID-19, the use and disposal of medical masks have created a series of ethical and environmental issues. The purpose of this paper is to study and evaluate the high temperature properties and thermal storage stability of discarded-mask (DM)-modified asphalt from a multi-scale perspective using molecular dynamics (MD) simulation and experimental methods. A series of tests was conducted to evaluate the physical, rheological, thermal storage stability and microscopic properties of the samples. These tests include softening point, rotational viscosity, dynamic shear rheology (DSR), Fourier transform infrared (FT-IR) spectroscopy and molecular dynamics simulation. The results showed that the DM modifier could improve the softening point, rotational viscosity and rutting factor of the asphalt. After thermal storage, the DM-modified asphalt produced segregation. The difference in the softening point between the top and bottom of the sample increased from 2.2 °C to 17.1 °C when the DM modifier admixture was increased from 1% to 4%. FT-IR test results showed that the main component of the DM modifier was polypropylene, and the DM-modified asphalt was mainly a physical co-blending process. MD simulation results show that the DM modifier can increase the cohesive energy density (CED) and reduce the fractional free volume (FFV) of asphalt and reduce the binding energy between base asphalt and DM modifier. Multi-scale characterization reveals that DM modifiers can improve the high temperature performance and reduce the thermal storage stability of asphalt. It is noteworthy that both macroscopic tests and microscopic simulations show that 1% is an acceptable dosage level.

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Section: Resultsmentioning

confidence: 99%

Multi-Scale Characterization of High-Temperature Properties and Thermal Storage Stability Performance of Discarded-Mask-Modified Asphalt

Hui

Yang

et al. 2022

Materials

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“…From the point of view of molecular motion, the glass transition of macromolecules corresponds to the critical states of the onset and freezing of chain segment motions. When the temperature exceeds the T g , the molecular chain segments in the asphalt begin to show signs of activity, and the molecular chain conformation changes by rotating within the single bond around the main chain, which results in a rapid increase in deformation and a dramatic decrease in the modulus [ 39 , 50 ].…”

Section: Resultsmentioning

confidence: 99%

Self-Healing Performance of Asphalt Concrete with Ca-Alginate Capsules under Low Service Temperature Conditions

Wang

Liu

et al. 2022

Polymers

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Calcium alginate capsules containing rejuvenators represent a promising method for asphalt concrete premaintenance, but their healing capacities under lower temperature conditions are still unknown. This paper investigated the healing performance of asphalt concrete containing calcium alginate capsules at low service temperatures. The Ca-alginate capsules were synthesized, and their morphology, compressive strength, thermal resistance, and relative oil content were evaluated. Besides, evaluations for the healing of asphalt concrete and the rejuvenator-release ratio of the capsules were determined via fracture-healing-refracture testing and Fourier-transform infrared spectrum experiments. Meanwhile, the glass transition temperature and rheological property of asphalt binder after compressive loading under different temperatures were explored via a differential scanning calorimeter and dynamic shear rheometer. The results showed that the capsules had good thermal resistance and mechanical strength. The capsules released less oil under −15, −10, and −5 ℃ than at 20 ℃, and the healing ratios of the asphalt concrete with the capsules at −15, −10, and −5 ℃ were obviously lower than that at 20 ℃. The released rejuvenator from the capsules could decrease the complex modulus and glass transition temperature of the asphalt binder. When compared with low service temperatures, the asphalt binder containing the capsules and serving at a high temperature has a better softening effect and low-temperature performance due to more oil being released.

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“…The linear viscoelastic regions (LVEs) of GMAs were determined by using DSR, MCR 302 (Anton Parr Inc., Graz, Austria). For asphalt, the higher the temperature is, the longer the LVE plateau is [23]. In view of the temperature sweep range (−30-120 • C), this paper selected −30 • C to carry out a strain sweep.…”

Section: Strain Sweepsmentioning

confidence: 99%

“…It is worth noting that the current cubic-element model with homogeneously distributed platelets can only be applied to a system containing a filler content below the percolation threshold. Four processes of asphalt binder mechanical state changing with temperature (the loss moduli approach the maximum plateau over the whole range of temperatures, the corresponding temperature is the glass transition temperature T g ; at temperature when G = G , viscoelastic asphalt transforms from viscoelastic solid to viscoelastic liquid; with G of asphalt decreases rapidly, asphalt changes from viscoelastic liquid to pure viscous Newtonian fluid) [23].…”

Section: Percolation Modelmentioning

confidence: 99%

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Rheological Properties of Graphene Modified Asphalt Binders

Yang

Zhou²,

Kang

2020

Nanomaterials

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Recently, low-cost, high-quality graphene can be obtained readily, so it is potential to prepare conductive graphene modified asphalts (GMAs). In this paper, GMAs were prepared with 0%, 2%, 4%, 6%, 8%, and 10% of graphene by weight of composites. Dynamic shear rheological experiments conducted from −30 to 120 °C illustrate that elasticity at above ambient temperatures and rutting resistance at higher temperatures are enhanced and, especially, the conceived percolation of GMAs occurs at graphene contents (GC) above 8% which were verified from three changes as GC increases, i.e., the curve characteristics of complex moduli, storage moduli at temperatures over 100 °C, temperatures when the phase angle reaches 90° and the trend of TG’=G’’. The modification mechanisms are different before and after percolation. Before the percolation threshold, graphene which has a molecular structure similar to asphaltene enhances asphalt, like increasing asphaltene components, and after threshold, graphene improves asphalt because of the formed graphene networks. Rotational viscosities test results show that the higher the GC is, the higher the operating temperatures are, but the operating temperatures are higher than 200 °C when GC is above 4%. The percolation helps to further develop conductive asphalt concrete for intelligence pavement, but the operating properties of GMAs need to be improved.

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Molecular dynamics study on the glass forming process of asphalt

Cited by 64 publications

References 30 publications

Multi-Scale Characterization of High-Temperature Properties and Thermal Storage Stability Performance of Discarded-Mask-Modified Asphalt

Multi-Scale Characterization of High-Temperature Properties and Thermal Storage Stability Performance of Discarded-Mask-Modified Asphalt

Self-Healing Performance of Asphalt Concrete with Ca-Alginate Capsules under Low Service Temperature Conditions

Rheological Properties of Graphene Modified Asphalt Binders

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