Investigation of Improving Stability in Desulfurized-Rubber-Modified Asphalt Using Cerium-Stearate Incorporation

To enhance the compatibility of high-content desulfurized-rubber-modified asphalt (DRMA), the innovative selection of cerium hard acid is employed in this study to investigate its impact on the compatibility of DRMA. The results indicate that when the optimal content of cerium stearate is 1%, the compatibility of the modified asphalt is improved. On the microscopic level, it is observed that the total heat absorption of the modified asphalt decreases and thermal storage stability is enhanced as measured by differential scanning calorimetry. On the macroscopic level, it gives the smallest difference in softening point, optimal storage stability, and best compatibility of the modified asphalt. Additionally, dissolution tests and adhesion tests demonstrate that the inclusion of cerium stearate increases the solubility of desulfurized rubber in asphalt and reduces the stripping rate of desulfurized-rubber particles on the asphalt surface, thereby decreasing phase separation and promoting the compatibility of DRMA. Furthermore, rheological tests indicate that cerium stearate improves both high-temperature and low-temperature performance of the modified asphalt. The addition of cerium stearate increases the dynamic shear modulus of the modified asphalt, maintaining good stability and elasticity under shear loading, with minimal change in low-temperature rheological properties and lower temperature sensitivity, indicating the best compatibility at this point. Finally, molecular-dynamics simulation data indicate that the addition of cerium stearate decreases the parameter difference in the dissolution of modified asphalt and enhances the binding energy of the modified asphalt, demonstrating the feasibility of cerium stearate in promoting the compatibility of modified asphalt.