Formulation of a New Rejuvenator and Its Regenerative Effect on Aged Asphalt

A massive amount of recycled asphalt pavement (RAP) is produced in road construction and maintenance, and using rejuvenators to rejuvenate RAP can have a significant economic benefit. At present, a biorejuvenator is used to rejuvenate RAP to alleviate the problem of low efficiency of the mineral oil rejuvenator. But the oxidation resistance of bio-oil is poor, it is easy to develop a wax deposit at low temperature, and the cost is much higher than mineral oil. To avoid these adverse effects of the biorejuvenator, a new mineral oil rejuvenator was developed by response surface methodology and solved the problem of low efficiency of mineral oil rejuvenator simultaneously. The rejuvenating effect of rejuvenator on aged asphalt was studied by a force ductility test (FDT), multiple stress creep and recovery (MSCR) test, Fourier transform infrared spectroscopy (FTIR) test, dynamic shear rheological test (DSR), antiaging performance test, and diffusion test. The results showed that the self-developed rejuvenator can restore the traditional physical properties of aged asphalt. In comparison with other commonly used rejuvenators, the self-developed rejuvenator had a significant antiaging performance and diffusion performance. Compared with aged asphalt, the chemical structure of recycled asphalt had not significantly changed, the aged asphalt was only diluted and dissolved by the rejuvenator. The addition of the rejuvenator improved the rheological properties, but was not conducive to high-temperature deformation resistance. The deformation recovery rate of recycled asphalt was positively correlated with the addition of the rejuvenator, and it showed excellent elastic deformation behavior under low stress. A comparison study indicated that a reasonable dosage of rejuvenator can restore the physical properties to the same approximate level as virgin asphalt. The recommended optimum dosage of the rejuvenator developed in this study was 5%. Finally, the prediction equation model of performance index and the dosage of rejuvenator was established, and the effect of the dosage of rejuvenator on the performance of recycled asphalt was quantitatively analyzed.