振动作用下沥青黏度与沥青混合料路用性能

为减少沥青混合料施工过程中大量的能源消耗和废气排放，在传统搅拌技术中加入振动功能以降低搅拌过程所需要的温度，采用布氏旋转黏度试验探究了振动参数(振动频率和幅值)和试验温度对SBS改性沥青的降黏效果，通过沥青的基本性能指标(针入度、软化点和延度)试验揭示2种振动方式对SBS改性沥青基本性能的影响，基于标准、高温与重载车辙试验，浸水马歇尔稳定度试验和冻融劈裂试验分别分析了振动拌和对SBS改性沥青混合料高温稳定性和水稳定性的影响。试验结果表明：振动拌和可以显著降低SBS改性沥青的黏度，提高改性沥青的流动性，且随着振动参数的增大，改性沥青降黏效果越好，最大降黏率可达14%；振动降黏可等效于温度降黏，且随着温度的升高，振动效应所带来的温度等效作用越显著；振动拌和结束后SBS改性沥青可恢复其黏稠属性，故基本性能不存在负面影响；当振动频率小于40 Hz时，SBS改性沥青混合料的动稳定度、残留稳定度和抗拉强度比均随振动频率的增大而增大，表明振动拌和可提高沥青混合料的高温稳定性和水稳定性，但当振动频率为50 Hz时，沥青混合料路用性能与振动频率为30 Hz时作用效果一致，表明增大振动频率对提高沥青混合料路用性能具有局限性。

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.