多聚磷酸对不同沥青的改性及改性机理研究

研究了多聚磷酸(PPA)掺量(质量分数)对不同沥青（TZ 70和SK 90）物理性能和流变性能的影响，并通过化学组分分析和原子力显微镜(AFM)观察探讨了PPA掺加后沥青化学组分和胶体结构的变化.结果表明：随着PPA掺量的增加，沥青的软化点和黏度提高，延度和针入度降低，复数模量增大，相位角减小，车辙因子明显增加.与TZ 70相比，PPA对SK 90物理性能和流变性能的改善更为明显.PPA的加入提高了沥青的热稳定性.与SK 90相比，PPA对TZ 70热稳定性的改善更为明显.PPA的加入促进了沥青胶质向沥青质的转化，使得沥青中的分散相出现明显的缔合，从而提高了沥青的刚性，改善了沥青的物理性能和流变性能.

Modification and Its Mechanism of Different Asphalts by Polyphosphoric Acid

The effects of dosage(by mass) of polyphosphoric acid(PPA) on physical and rheological properties of asphalts(TZ 70, SK 90) were investigated, the changes of chemical composition and colloid structure of the asphalts were studied by chemical composition and atomic force microscopy(AFM) analyses. The results show that the softening point, viscosity, complex modulus and rut factor of the asphalts are increased with the increment of dosage of PPA, while the ductility, penetration and phase angle of the asphalts are decreased with the increment of dosage of PPA. Compared with TZ 70, the physical and rheological properties of SK 90 are improved more obviously. The thermo stability of the asphalts is improved with the introduction of PPA. The thermo stability of TZ 70 is more obviously improved than that of SK 90. After PPA added, the transformation of asphalt from resins to asphaltenes is promoted, which contributes to the association of the dispersed phase and increases the stiffness of asphalt. As a result, the physical and rheological properties of the asphalts are improved remarkably.