Study on the microscopic characteristics and rheological properties of thermal-oxidative aged and virgin-old recycled asphalts

Qin, Yue; Meng, Yongjun; Lei, Jiechao; Fu, Tao; Xu, Ruiguang; Yang, Xiaolong; Zhao, Qixiong; Xi, Chenchen

doi:10.1016/j.eurpolymj.2021.110499

Cited by 30 publications

(8 citation statements)

References 39 publications

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“…The rheological response of a polymer is notably influenced by variations in its molecular configuration. 36,37 To ascertain the occurrence of reactions between TPU and SAG, a comparison of rheological behaviors across diverse TPU samples proves insightful. In Figure 4a, the correlation between η* and frequency is depicted for both TPU and modified TPU samples.…”

Section: Resultsmentioning

confidence: 99%

Tensile and heat resistance behavior of modified thermoplastic polyurethane elastomer in anisotropic neodymium‐iron‐born bonded magnet

Qu,

Wu,

et al. 2023

J of Applied Polymer Sci

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The emergence of anisotropic neodymium‐iron‐boron (NdFeB)‐bonded magnets with high energy density and freedom of shape design is effective in minimizing the dimensions and mass of electric motors. However, limitations in mechanical strength and heat resistance at elevated temperatures hinder their further application. To overcome these challenges, we present a novel approach to enhance the tensile strength and heat resistance of the NdFeB‐bonded magnet involving the modification of thermoplastic polyurethane (TPU) through the melt‐mixing method with a styrene–acrylonitrile‐glycidyl methacrylate terpolymer (SAG) modifier and engineered TPU was then employed in fabricating NdFeB‐bonded magnets via calendering molding. The microstructure of the magnets exhibited aligned NdFeB particles due to mechanical stress during calendering molding, which results in anisotropy. Interestingly, the magnetic properties of bonded magnets based on modified TPU remain almost the same compared to their unmodified counterparts, showcasing a maximum energy product of around 12 MGOe. The mechanical tests demonstrated a maximum 32.4% increase in the tensile strength of bonded magnets based on modified TPU. A progressive shift to a higher temperature (100 to 120°C) of magnet samples fractured occurs in the heat resistance measurement of the bonded magnets based on modified TPU, meaning improvement in heat resistance of NdFeB bonded magnets.

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Section: Resultsmentioning

confidence: 99%

Tensile and heat resistance behavior of modified thermoplastic polyurethane elastomer in anisotropic neodymium‐iron‐born bonded magnet

Qu,

Wu,

et al. 2023

J of Applied Polymer Sci

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“…Studies have shown that the chemical components of asphalt were closely related to rheological properties and road performance [26,27]. Figure 2 shows that the contents of asphalt resins, saturates and aromatics decreased and the asphaltenes increased after the aging of aqueous PAV.…”

Section: Four-component Testmentioning

confidence: 98%

Study of the Molecular Components and Rheological Properties of Asphalt after Long-Term Aging under the Action of Moisture

Luo

Xie

Zhao³

et al. 2022

Sustainability

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This study aimed to investigate variations and relationships between molecular components and rheological properties during the long-term aging of SBS-modified asphalt by the action of moisture. The chemical components and changes in molecular weight during aqueous PAV aging were observed using a four-component test and GPC test, and these morphological changes were quantified. Viscosity tests, time-scan tests and damage-healing tests were carried out to investigate the rheological properties during the aging process. Finally, the mechanism of asphalt aging under the influence of moisture was discussed. The results showed that moisture facilitated the long-term aging of asphalt and complicated the aging behavior under pressure-aging conditions. The dissolution of certain hydrophilic groups may be responsible for the decrease in resin content. The fatigue and self-healing properties of asphalt were weakened by moisture during the aging process. This was mainly attributed to a decrease in the composition of the asphalt colloidal dispersion medium, which resulted in earlier and faster development of microcracks under repeated loading as well as retardation in the rate of asphalt surface approach, wetting and spreading. Under long-term aging in the presence of moisture, the molecular components of the asphalt showed significant correlations with the rheological properties. The results of this study can contribute to further explaining the influence of moisture on the thermal-oxidative aging of asphalt.

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“…The polydispersity parameter obtained from GPC may be a useful tool to describe and predict the evolution of the rheological performance of asphalt. Some other research also shows that an increase in the high molecular weight of asphalt could increase the viscosity of bituminous binders [4]. Moreover, You et al [125] used a 12-component bitumen model in a molecular dynamics simulation, which considers an improved Amberer-Cornell force field.…”

Section: Correlation Between Rheological Properties and Molecular Str...mentioning

confidence: 99%

“…Approximately 70% of existing pavement structures were built using asphalt as the binders [3]. However, due to complex factors such as high temperature, moisture, oxygen, solar radiation, reactive oxygen species such as NO x and O 3 , etc., the asphalt will suffer ageing during its service life [4][5][6][7]. In this process, the asphalt undergoes chemical component migration, microstructure transformation, and performance change [8,9]; it is transformed from the original "soft" structure to a "rigid and brittle" structure after aging [10].…”

Section: Introductionmentioning

confidence: 99%

Multiscale Evaluation of Asphalt Aging Behaviour: A Review

Zhen

Kang²,

Liu

et al. 2023

Sustainability

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The performance of asphalt pavement will deteriorate gradually due to oxidation, also named the ageing of asphalt binders. In this study, the research progress on the multiscale evaluation of asphalt aging behaviour in the past decade was reviewed to further analyse the evolution law of asphalt aging behaviour and determine the asphalt aging mechanism. Firstly, artificial aging methods were introduced, the factors affecting asphalt aging behaviour were analysed, and the changes of asphalt properties before and after aging were identified. Secondly, the methods and research progress in terms of the evaluation of asphalt aging degrees were summarised from the macro-, mesoscopic-, micro-, and nanoscales. Finally, considering extensively studied rheological properties as an example, the correlations among the rheological properties of asphalt in the aging process and the conventional physical properties, chemical composition, microscopic properties, nano-molecular dynamics, and other parameters were analysed. The results show that various scales are interrelated, and the multiscale evaluation of asphalt aging can provide a more comprehensive prediction of the extent of asphalt aging. The correlation between multiple scales enables a thorough analysis of the mechanism of asphalt aging and the evaluation of asphalt aging behaviour at multiple scales.

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Study on the microscopic characteristics and rheological properties of thermal-oxidative aged and virgin-old recycled asphalts

Cited by 30 publications

References 39 publications

Tensile and heat resistance behavior of modified thermoplastic polyurethane elastomer in anisotropic neodymium‐iron‐born bonded magnet

Tensile and heat resistance behavior of modified thermoplastic polyurethane elastomer in anisotropic neodymium‐iron‐born bonded magnet

Study of the Molecular Components and Rheological Properties of Asphalt after Long-Term Aging under the Action of Moisture

Multiscale Evaluation of Asphalt Aging Behaviour: A Review

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