The effect of moisture on the adhesion properties at the interface between asphalt and recycled aggregates

ABSTRACT

The effect of moisture on the adhesion strength at the asphalt and recycled concrete aggregate (RCA) interface plays an important role in the durability performance of asphalt pavements. In this study, a universal testing machine was used to analyse the effect of moisture on the asphalt adhesion rate at the interface. Scanning electron microscopy was utilised to observe the changes in the micro-morphology of the interface before and after the effect of moisture. The effect of moisture on the interface between asphalt and recycled aggregate was investigated using molecular dynamics (MD) simulation to explore the microscopic mechanism. The results showed that the residual rate of asphalt on the surface of concrete specimens decreased from 80.2% to 34.7% after 72 h of water bath curing. The micro-morphology at the asphalt–RCA interface changed significantly before and after the action of water. Interfacial water affects the concentration distribution of asphalt components at the interface mainly by changing the nanostructure within the asphalt binder. This leads to worse adhesion properties at the asphalt–RCA interface. This study provides deeper insights into understanding water damage at the asphalt–RCA interface and provides ideas for improving the durability of the material.

KEYWORDS:

• Asphalt mixture
• moisture
• asphalt–RCA interface
• adhesion
• molecular dynamics

Disclosure statement

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

Additional information

Funding

This work was financially supported by Fundamental Research Fund of Natural Science Foundation of China (No. 52208434), the Central Public Welfare Research Institute (No. 2020-9049), Natural Science Foundation of Henan Province (No. 222300420142), Postdoctoral Fund of Henan Province; Science and Technology Project of Henan Province (No. 192102310229), China Post-doctoral Science Foundation (No. 2022M711079), Young backbone teachers plan of Henan University of Technology (No. 21420156).