Microstructural characterisation of reclaimed asphalt pavement with rejuvenators

ABSTRACT

Reclaimed asphalt pavement (RAP) is the deteriorated pavement material, containing aged binder and aggregates. A rejuvenator is normally added to the mixture to reduce its stiffness, by blending with the aged binder and changing the properties of the mixture. Therefore, it is necessary to have an insight into the microstructure of the RAP and rejuvenated RAP. In this study, waste engine oil (WEO), waste vegetable oil (WVO) and waste grease (WG) are used as rejuvenators, at different dosages. The interaction between the rejuvenator and RAP is evaluated through microscopic analysis, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The microscopic analysis has provided the orientation and distribution of the aggregate, depicting the significant increase in coating of aged binder on the RAP with the increase in the rejuvenator dosage. The FTIR and XRD results have shown that rejuvenator has restored the asphaltenes and maltenes ratio and fluidity of the RAP. WG has comprehensively enhanced the asphaltenes and maltenes ratio, compared to the WEO and WVO. However, microscopic analysis suggests that the WG has high agglomeration. Overall, it is concluded that 6% WVO is a perfect dosage to enhance fluidity of the RAP.

KEYWORDS:

• Reclaimed asphalt pavement
• rejuvenators
• waste engine oil
• waste vegetable oil
• waste grease
• microscopic analysis
• FTIR spectroscopy
• XRD analysis

Acknowledgement

The authors would like to acknowledge Dr Mohan K from School of Civil Engineering for helping us to perform microscopic analysis in geosciences lab and the support of the School of Advanced Sciences at Vellore Institute of Technology Chennai for conducting the FTIR and XRD analysis. Also, authors appreciate the anonymous reviewers for their insightful comments and criticism, which have improved the manuscript significantly.

Disclosure statement

No potential conflict of interest was reported by the author(s).