Quantitative study on regeneration mechanism of warm mixed recycled asphalt. (1st July 2023) - Jiangsan, Hu
Abstract: The warm mix recycling technology of asphalt pavement can improve the resource utilization rate of solid waste in highway construction industry on a large scale, and reduce the emission of harmful gases (NOX, CO2, benzopyrene, etc.) during road construction. It is one of the effective ways to achieve carbon peak and carbon neutralization strategy in highway construction industry. The purpose of this study is to analyze the regeneration mechanism of warm mixed recycled asphalt from the perspective of quantitative research systematically, and to provide scientific basis for the popularization and application of this technology. In this study, the basic performance test, rheological performance test, microstructure test, chemical composition and molecular weight test of warm mixed recycled asphalt with different content of reclaimed asphalt pavement(RAP) were carried out to clarify the performance change, physical and chemical change mechanism of recycled asphalt during the process of warm mixed regeneration. The results show that: (1) The basic performance of asphalt can be restored to the level of matrix asphalt after regeneration, but the viscoelasticity can not be restored to the level of matrix asphalt, and the anti-aging performance of recycled asphalt is worse than that of matrix asphalt. (2) Microscope technology + digital image processing technology can effectively observe and analyze the microstructure of warm mixed recycled asphalt. The results of atomic force microscopy(AFM) showed that the formation of ' bee structures ' required a fixed proportion of each component of asphalt. The use of regenerant adjusted the asphalt component, which could make the recycled asphalt appear ' bee structures '. The regeneration process mainly increased the light components of asphalt, but the results of optical microscope analysis showed that the number of micelles did not increase significantly. (3) The main change during the process of warm mixed asphalt regeneration is physical reconciliation, no chemical changes (no new functional groups). However, the configurational change occurred in this process, and the functional groups involved in the configurational change did not exceed 15% of the total number; the process of configurational change is mainly from macromolecule to medium molecules, and the macromolecules involved in the change do not exceed 6% of the total number.