Enhanced oxidation aging resistance of asphalt binder with slow-release porous calcium carbonate microspheres loaded with asphalt rejuvenator

To enhance the oxidation aging resistance of asphalt binder, slow-release porous calcium carbonate (CaCO3) microspheres loaded with asphalt rejuvenator were proposed. The porous calcium carbonate microspheres fabricated by a double decomposition method regulated by polyacrylic acid (PAA) and sodium dodecyl sulfonate (SDS) were used as carriers for the asphalt rejuvenator. The test results showed that the porous CaCO3 microspheres possessed higher specific surface areas and porosities, and the weight ratio of the rejuvenator loaded on the CaCO3 microspheres was up to15%. Frequency sweep test results showed that the complex modulus of the asphalt binder added with rejuvenator-loaded CaCO3 microspheres decreased after aging. When the content of the CaCO3 microspheres added in asphalt binder reached 70%, the complex modulus is even less than that of neat asphalt. Additionally, the slow-release mechanism of the CaCO3 microspheres loaded with rejuvenator was studied based on molecular dynamics simulations. The simulation results also showed that the composition and structure of the molecule played an important role in the diffusion ability. This study provides a reference for developing a new method to delay the oxidation aging of asphalt, and it provides theoretical and experimental data support for the design of oxidation-aging resistance asphalt mixtures.