Development of Bioregenerant and Its Potential Application: Investigation for Regeneration of RAP Materials

Abstract

To achieve efficient utilization of reclaimed asphalt pavement (RAP) materials, a bioregenerant (BR) was developed in this research, and waste vegetable oil (WVO), alkylphenol polyoxyethylene ether (APEO), plasticizer [tributyl acetylcitrate (ATBC)] and tackifying resin (FTR) were chosen as components of the regenerant. The composition ratio of BR was designed based on the response surface method (RSM), and the optimal BR dosage and the regeneration effect of BR on the bioregenerated mixture (BRM) with different RAP contents were determined and investigated. Results showed that the optimal composition ratio of BR was found to be WVO-APEO-ATBC-FTR=100:2:23:10. The addition of BR significantly reduced the high-temperature stability and aging resistance of the mixture, but improved its low-temperature cracking resistance and fatigue resistance. Additionally, BR prominently contributed to the improvement for the water stability of the regenerated mixture, and its regeneration effect was found to be similar to that of two commercial regenerants, although excessive BR led to the decline of water stability. Moreover, the high-temperature stability and aging resistance of BRM when mixed with 20%, 30%, and 40% RAP were similar to those of the new asphalt mixture (NAM). At 20%, 30%, and 40% RAP content, both the low-temperature cracking resistance and fatigue resistance of BRM met the requirements. However, when the RAP content exceeded 40%, the water stability of BRM went beyond the specification limit. Taking into account the overall road performance, it is suggested that the optimal BR dosage is 5%–9%, and the maximum RAP content ensuring the road performance of BRM meets the requirements is 40%. These research findings will contribute to addressing the stacking problem of reclaimed asphalt pavement materials and environmental pollution, aligning with green and environmentally friendly sustainable development principles.