Asphalt viscosity and asphalt mixture pavement performance under vibration

To reduce the vast energy consumption and exhaust emissions during the construction of asphalt mixture, a vibration function was added to the traditional mixing technology to reduce the temperature required for the mixing process. The effects of vibration parameters (vibration frequency and amplitude) and test temperature on the viscosity reduction for the SBS modified asphalt were investigated by the Brockfield rotational viscosity test. The basic performance indicators (penetration, softening point, and ductility) of the asphalt were tested to reveal the effects of two vibration methods on the basic performance of SBS modified asphalt. Based on the standard, high-temperature and heavy load rutting tests, water immersion Marshall stability test, and freeze-thaw splitting test, the effects of vibratory mixing on the high-temperature stability and water stability of SBS modified asphalt mixture were investigated separately. Test results show that the vibratory mixing can significantly reduce the viscosity of SBS modified asphalt, improve the mobility of the asphalt. With the increase in the vibration parameters, the viscosity reduction effect of modified asphalt is better, and the maximum viscosity reduction rate is up to 14%. The viscosity reduction by vibration can be equivalent to the temperature viscosity reduction, and the temperature equivalent effect brought by the vibration effect is more significant with the increase in temperature. After the vibratory mixing, the viscosity property of SBS modified asphalt can be recovered, and hence, no negative impact is exerted on its basic performance. When the vibration frequency is less than 40 Hz, the dynamic stability, residual stability, and tensile strength ratio of SBS modified asphalt mixture increase with the rise in the vibration frequency. It is indicated that the vibratory mixing can improve the high-temperature stability and water stability of asphalt mixture. However, when the vibration frequency is 50 Hz, the pavement performance of asphalt mixture is consistent with that at 30 Hz. In other words, the effect of vibration frequency increase on the pavement performance of asphalt mixture is limited. 7 tabs, 9 figs, 30 refs. © 2023 Chang'an University. All rights reserved.