Critical considerations and effective assessment of extraction and recovery processes of RAP

Zhong, Haobai; Huang, Weidong; Lin, P.; Zhou, L.; Lv, Quan

doi:10.1016/j.conbuildmat.2023.133039

Critical considerations and effective assessment of extraction and recovery processes of RAP

Title

Critical considerations and effective assessment of extraction and recovery processes of RAP

Author

Zhong, Haobai (Tongji University)
Huang, Weidong (Tongji University)
Lin, P. (TU Delft Pavement Engineering)
Zhou, L. (University of Nottingham)
Lv, Quan (Tongji University)

Date

2023

Abstract

With the increasing shortage of resources, the reuse of recycled asphalt pavements (RAP) in pavement engineering is considered as a sustainable technology. Challenges posed by common extraction and recovery methods may result in misjudgment of asphalt pavement performance. In this study, we investigate the optimization of extraction and recovery processes in recycled asphalt pavement (RAP) recycling, aiming to promote sustainable development within the pavement engineering sector. We prepared eleven asphalt samples to simulate common extraction and recovery scenarios, using virgin SBS-modified asphalt as a reference. Employing Fourier Transform Infrared (FTIR) analysis, thermogravimetric analysis (TGA), and Dynamic Shear Rheometer (DSR) testing, we assessed the samples' rheological and chemical properties. We pointed out three common but easily overlooked problems in the extraction and recovery process, namely residual mineral powder, residual trichloroethylene, and incomplete extraction. Residual mineral powder and trichloroethylene greatly influence extraction recovery accuracy; high-speed centrifugation effectively addresses trichloroethylene, but completely removing mineral powder remains challenging. Accurate evaluation of residual substances in recycled asphalt is achievable through FTIR, TGA, and rheological tests, providing valuable insights for material selection and processing. Additionally, it is crucial to fully recover the binder from RAP for precise performance evaluation, as the binder's interior exhibits lower aging levels compared to the surface. This aging heterogeneity should be considered when assessing RAP performance and developing effective rehabilitation strategies. Our findings hold significant implications for enhancing the efficiency and effectiveness of extraction and recovery processes in RAP recycling, ultimately contributing to sustainable development in pavement engineering.

Subject

Aging heterogeneity
Extraction optimization
RAP recycling
Residual substances
Sustainability

To reference this document use:

http://resolver.tudelft.nl/uuid:39838976-4df2-4d10-8ea8-f8df88558a63

DOI

https://doi.org/10.1016/j.conbuildmat.2023.133039

ISSN

0950-0618

Source

Construction and Building Materials, 403

Part of collection

Institutional Repository