氯盐冻融对疏水性纳米白炭黑改性沥青性能的影响

Influence of Chlorine Salt F-T Cycles on Properties of Hydrophobic Nano-Silica Modified Asphalt

摘要:

基于基础性能试验、动态剪切流变（DSR）试验、热重分析（TGA）试验和红外光谱（FTIR）试验，对疏水性纳米白炭黑改性沥青在氯盐冻融环境下的劣化进程进行了系统研究。试验结果表明，疏水性纳米白炭黑的掺入可以有效抑制沥青在氯盐冻融环境下的劣化进程。基础性能试验和DSR试验表明经过30次氯盐冻融循环后，疏水性纳米白炭黑改性沥青的针入度增加了17.46%，软化点提高了5.82%，黏度增加了7.76%，车辙因子提升了17%~54%，其增长幅度远小于基质沥青，说明疏水性纳米白炭黑的掺入可以有效降低沥青对氯盐冻融环境的敏感度。TGA试验数据表明了疏水性纳米白炭黑可以提高沥青的热稳定性，但是疏水性纳米白炭黑改性沥青的热稳定性受氯盐冻融环境影响较为明显，这是由于疏水性纳米白炭黑在改性沥青过程中键合作用形成的连接键在氯盐冻融环境下更容易被破坏。通过FTIR试验可以发现在氯盐冻融环境下沥青发生了化学反应，但无新官能团出现。其中游离烃基（3 676 cm^-1）变化最为明显，可以更为有效地描述2种沥青在氯盐冻融环境下的劣化进程。在氯盐冻融环境下，疏水性纳米白炭黑改性沥青各官能团无明显变化，分布较为稳定，具有较高的性能稳定性。

Abstract:

Based on the basic performance test, i.e., the dynamic shear rheological test (DSR test), the thermogravimetric analysis test (TGA test), and the Fourier transform infrared spectrometer (FTIR test), the deterioration characteristics of hydrophobic nano-silica modified asphalt inchlorine salt F-T cycles were systematically studied. The experimental results show that the incorporation of hydrophobic nano-silica can effectively inhibit the deterioration process of asphalt inchlorine salt F-T cycles. The basic performance test and DSR test indicate that the penetration, softening point and viscosity of hydrophobic nano-silica modified asphalt increases by 17.46%, 5.82%, and 7.76%, respectively, and the rut factor increases by 17% to 54%.Besides, the growth rate of hydrophobic nano-silica modified asphalt is much smaller than that of base asphalt, which indicates that the incorporation of hydrophobic nano-silica could effectively reduce the sensitivity of asphalt to the chlorine salt F-T cycle. The TGA test suggests that hydrophobic nano-silica could improve the thermal stability of asphalt, but the thermal properties of hydrophobic nano-silica modified asphaltis significantly affected by chlorine salt F-T cycles, which may be due to the chemical bond formed between the hydrophobic nano-silica and asphalt is more easily destroyed in chlorine salt F-T cycles. The FTIR test indicates that the chemical reaction of asphalt occurs in chlorine salt F-T cycles, but no new functional groups appear. The free hydrocarbon group (3 676 cm^-1) has the mostsignificant change, which could effectively describe the damage process of twoasphalt samplesin chlorine salt F-T cycles. There is no obvious change in the functional groups of hydrophobic nano-silica modified asphalt in chlorine salt F-T cycles, and the distribution is relatively stable, with a high performance stability.