# High-Temperature Rheological Properties of Asphalt Mortar Modified with Spent FCC Catalysts
## 3 Results and Discussion
### Mscr  
Figure 8 illustrates the correlation between the doping amount of S-FCC-Cs in the five FCC waste catalyst-modified asphalt mastics and the deformation recovery rates R0.1 and R3.2 under test conditions of 0.1 kPa and 3.2 kPa at 60 \({}^{\circ}\)C. From Figure 8, it can be observed that the deformation recovery rate R of S-FCC-C-modified asphalt mastic generally increases as the doping amount of S-FCC-Cs increases. This indicates that the overall resilience performance of S-FCC-C-modified asphalt mastic improves with higher levels of alternative doping, resulting in a higher percentage of deformation recovery. Under both stress conditions, the majority of S-FCC-C-modified asphalt mastics exhibited a marked increase in the growth rate of resilient energy at 80% doping, indicating a significant increase in the amount of structural asphalt adsorbed by S-FCC-Cs at high doping levels. This conversion led to a greater proportion of viscous components in the asphalt mastic being transformed into elastic components, resulting in a significant improvement in high-temperature performance. Interestingly, the R3.2 value of JX asphalt mortar increased sharply with the increase in JX dosage, indicating the excellent deformation recovery ability of JX asphalt mortar. It was found that there was a slight phase separation phenomenon that appeared in the JX asphalt mortar during the experiment. The phase separation of JX from the asphalt may lead to the movement of asphalt on JX, which should be the reason that the JX asphalt mortar exhibited the best resilience among the five asphalt mortars under the stress of 3.2 kPa. Jnr (0.1/3.2) was polynomially fitted, and the corresponding fitted curves and functions are presented in Figure 9, along with the detailed results in Tables 3 and 4. Figure 9 displays the graphical representation of the average irrecoverable creep flexibility, Jnr0.1 and Jnr3.2, as they vary with the S-FCC-C admixture levels in the five FCC spent catalyst-modified asphalt mastics at 60 \({}^{\circ}\)C.  
Figure 9 indicates a well-fitted quadratic function between the irrecoverable creep flexibility of S-FCC-C-modified asphalt mastic and the S-FCC-C alternative doping, with an R\({}^{2}\) value exceeding 0.9. The irrecoverable creep flexibility gradually decreases with increasing S-FCC-C doping, and the slope of the curve decreases accordingly. This indicates that the incorporation of S-FCC-Cs enhances the resistance to permanent deformation and improves the high-temperature performance of the asphalt mastic, with a more pronounced effect at higher doping levels. At lower doses, the variation in the S-FCC-Cs dosage has a significant impact on the Jnr of the asphalt slurry, whereas at higher doses, the influence becomes less pronounced. Increasing the replacement dosage of the FCC spent catalyst significantly enhances the high-temperature performance of the asphalt slurry at lower doses, but the effect gradually diminishes at higher doses. Furthermore, it can be seen from Figure 9 that the Jnr value of JX asphalt mortar is higher than that of the other four, which is consistent with the rutting factor results. Figure 10 presents the absolute value of the irrecoverable creep flexibility difference, Jnr-diff, plotted against the S-FCC-Cs replacement doping. In the current experimental study, it was observed that Jnr\({}_{0.1}\) was higher than Jnr\({}_{3.2}\) regardless of the presence or absence of S-FCC-Cs substitution. This finding contrasts with conventional MSCR test results for asphalt materials. Consequently, negative values of Jnr-diff were calculated for all test groups. Further investigation of the relevant literature revealed that such results are attributed to the filler volume filling-effect resulting from the filler ratio [43, 44]. In asphalt mastics with a lower powder content, the load is primarily borne by the asphalt component under both low- and high-stress conditions.