旋转蒸发器法回收沥青及其改进方法研究

Test and improvement of recovering asphalt with rotary evaporator method

为研究旋转蒸发器法回收沥青胶结料的合理性,采用常规性能试验(针入度、软化点、延度、135℃布氏黏度试验)、SHRP流变试验(动态剪切流变仪(DSR)温度扫描试验、多应力重复蠕变(MSCR)试验)和傅里叶变换红外光谱(FTIR),从物理指标、流变行为和化学特性对比分析了原样沥青和回收沥青的技术性质,并探讨了旋转蒸发器法回收沥青的改进措施和判断回收沥青是否残留三氯乙烯或产生老化的新指标.结果表明:通过标准旋转蒸发器法回收的沥青仍残留部分三氯乙烯并产生了老化;利用常规指标偏差系数、三氯乙烯残留指数It、羰基指数Ic、亚砜基指数Is、温度敏感性指标IGTS和应力敏感性指标Jnr-diff能有效判别回收沥青是否残留三氯乙烯或者产生老化;采用改进旋转蒸发器法在4.6 kPa负压、130℃高温蒸馏2.0 h时回收的沥青技术性质与原样沥青基本一致,因此采用这种推荐的旋转蒸发器法回收沥青是合理的.

To investigate the rationality of recovering asphalt binder with the rotary evaporator method, conventional performance tests(penetration, softening point, ductility, 135 ℃ Brookfield viscosity test), rheological tests of SHRP(dynamic shear rheological(DSR) temperature scanning test, multiple stress creep recovery(MSCR) test) and Fourier transform infrared spectroscopy(FTIR) are employed to analyze the technical properties of the original asphalt and the recovered asphalt from physical indicators, rheological behaviors and chemical characteristics. The improvement measures of recovering asphalt with the rotary evaporator method and the new index to judge whether trichloroethylene is remained or the recovered asphalt is aged are studied. The results show that the residual trichloroethylene and the aging are still observed in the recovered asphalt by the standard rotary evaporator method. And the coefficient of variation of conventional performance index, trichloroethylene index It, carbonyl index Ic, sulfoxide index Is, temperature sensitivity index IGTS and stress sensitivity index Jnr-diff can accurately measure whether the recovered asphalt remains trichloroethylene or produces aging. The technical properties of the recovered asphalt by the improved rotary evaporator method at a negative pressure of 4.6 kPa, 130 ℃ high temperature, distillation of 2.0 h are basically the same as those of the original asphalt. So the recommended recovery method with the rotary evaporator is reasonable.