Research on the Fatigue Properties of Rejuvenated Asphalt Prepared by Waste Cooking Oil Pre-Desulfurized Crumb Tire Rubber

Fatigue cracking has hitherto been a crucial constraint on the development of reclaimed asphalt pavements attributed to the performance of rejuvenated asphalt binder. Therefore, it is extremely significant to evaluate the fatigue performance of rejuvenated asphalt precisely and objectively and to improve the fatigue life of rejuvenated asphalt binders. With preceding research in our group, this paper investigated the fatigue properties of waste rubber/oil (WRO) rejuvenated asphalt and universal rejuvenated asphalt by dynamic shear rheometer test (DSR). The applicability of common fatigue life evaluation indexes and the response to internal and external influences on the fatigue performance of rejuvenated asphalt were analyzed. It is demonstrated that N(p20) corresponding to the mutagenesis of phase angle is physically significant and independent of the parameters including rejuvenator type, loading mode and loading level, which was recommended as the evaluation index for fatigue life of rejuvenated asphalt in this paper. The fatigue performance of both WRO and universal rejuvenated asphalt is found to decrease with loading frequency and loading level, but the fatigue life of WRO rejuvenated asphalt is comparatively superior to the latter, particularly at high loading frequencies and levels. Influenced by waste tire crumb rubber (WTCR), increasing the proportion of WTCR can improve the fatigue life of rejuvenated asphalt. When compared to other rejuvenated asphalt, RWRO@55 rejuvenated asphalt shows better fatigue performance and its fatigue life rebounds at high loading frequency. Consequently, the recommended mastic–oil ratio is 5:5. However, when the rheological recoverability compensation is considered, the fatigue lifetime evaluation of rejuvenated asphalt will be changed significantly, and therefore the fatigue performance evaluation of rejuvenated asphalt should consider the influence of rheological recoverability to develop a comprehensive evaluation system.