基于原子力显微镜的沥青再生机理

沥青的老化严重影响了沥青混合料在实际应用中的耐久性,为了研究沥青的老化和再生机理,将基质沥青进行SHRP(strategic highway research program)老化,利用原子力显微镜(atomic force microscope, AFM)和动态剪切流变仪(dynamic shear rheometer, DSR)技术研究不同掺量的基质沥青和再生剂对老化沥青的再生效果。结果表明:基质沥青和再生剂均能对老化沥青产生再生效果,且随着它们掺量的增大,再生效果变好;老化沥青表面微观结构粗糙不均匀,基质沥青和再生剂的加入有效改善其表面微观形貌,降低其黏附力和粗糙度指标,同时使老化沥青相位角增大、复数剪切模量和抗车辙因子减小;温度的升高有助于再生剂在老化沥青中的扩散。可见再生剂的主要再生机理是增加并扩散老化沥青中缺失的组分。

Study on Asphalt Regeneration Mechanism Based on Atomic Force Microscope

Aging of asphalt binder seriously affects the durability of asphalt mixture in practical application. To study the aging and regeneration mechanism of asphalt binder, SHRP (strategic highway research program) aging of virgin asphalt binder was studied. The regeneration effect of a virgin asphalt binder and a rejuvenator with different dosage on aged asphalt binder was studied by atomic force microscope and dynamic shear rheometer. The results show that both a virgin asphalt binder and a rejuvenator can produce regeneration effect on aged asphalt binder. And with the increased of their dosage, the regeneration effects become better. The surface microstructures of aged asphalt binders were rough and uneven. The addition of a virgin asphalt binder and a rejuvenator improved its surface microstructure and reduced its adhesion and roughness indexes. At the same time, the phase Angle of aging asphalt binder increased, complex shear modulus and rutting resistance factor decreased. The increased temperature was helpful to the diffusion of a rejuvenator in aged asphalt binders. It can be seen that the main regeneration mechanism of the rejuvenator was to increase and diffuse the missing components in aged asphalt binder.