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In order to investigate the dynamic mechanical properties of polyphosphoric acid (PPA) and SBS co-modified asphalt mixtures, uniaxial compression dynamic modulus tests were conducted. The influences of temperature and frequency on the dynamic modulus and phase angle were analyzed. Additionally, dynamic modulus and phase angle master curves were constructed based on the modified Havriliak-Negami (HN) model. A comparative analysis was also performed with SBS-modified asphalt mixtures. The results indicate that both types of asphalt mixtures exhibit similar trends in dynamic modulus and phase angle variations with changes in temperature and frequency. The HN model accurately fits the master curves of dynamic modulus and phase angle for both asphalt mixtures. In comparison to SBS-modified asphalt mixtures, the phase angle of PPA+SBS co-modified asphalt mixtures decreases at -10, 20, and 50 °C, while the dynamic modulus decreases at -10 °C, changes minorly at 20 °C, and increases at 50 °C. Over a wide frequency range, PPA+SBS co-modified asphalt mixtures exhibit increased dynamic modulus and decreased phase angle at high temperatures and low frequencies, while they show decreased dynamic modulus and relatively stable phase angle at low temperatures and high frequencies. These findings suggest that PPA+SBS comodification endows asphalt mixtures superior dynamic mechanical properties. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jiangsu University (Natural Science Edition) / Jiangsu Daxue Xuebao (Ziran Kexue Ban) is the property of Editorial Department of Journal of Jiangsu University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The microwave thermal induced healing properties of asphalt mixture with different dosage of Fe3O4-SiC were studied. Firstly, the effect of Fe3O4-SiC on the microwave heating efficiency of asphalt mixture was studied by microwave heating. Then, the fluidity of asphalt was characterized by frequency scanning and temperature scanning tests of DSR, and the healing effect of asphalt was evaluated by LAS tests of loading-intermittent loading mode. Finally, the healing effect of asphalt mixture was studied by SCB test of destruction-healing-failure mode. The experimental results show that with the increase of Fe3O4-SiC content, the microwave heating efficiency of asphalt mixture is improved, and the heating rate of 25%, 50% and 75% is increased by 27.41%, 43.44% and 77.26% compared with the blank group, respectively. Frequency scanning, temperature scanning and LAS tests show that high temperature promotes asphalt flow and is beneficial to healing. SCB test results show that when the content of Fe3O4-SiC is 50%, it is more suitable for microwave heat-induced healing of asphalt mixture, which not only reduces the heating time, but also maintains a certain healing effect. [ABSTRACT FROM AUTHOR]

Isocyanate modified liquid was prepared by isocyanate and diluted asphalt. Then, isocyanate modified asphalt cold patch asphalt mixture was prepared by combining isocyanate modified liquid with aggregates. Crosslinking reaction was used to improve the performance of cold patch asphalt mixture. The experimental results show that the modified liquid exhibits good short-term storage stability. By adjusting the dosage of PM-200 and PPU-1102 isocyanate, the viscosity and the reactivity of the system can be effectively regulated, from which the mechanical properties and water damage resistance of the cold patch asphalt mixture can be well adjusted. When the proportion of diluted asphalt, PM-200 and PPU-1102 in the modified liquid are 50%, 10% and 40%, respectively, the Marshall stability and the residual stability of the cold patch asphalt mixture with 6% liquid content reaches 24.8kN and 86.1%, respectively, which are close to those of the hot asphalt mixture. Field experiments show that compared with traditional material, the isocyanate modified cold patch asphalt mixture exhibits higher durability. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)