Investigation of self-healing properties of nanoclay-modified asphalt binder using two-piece healing test

Abstract

Asphalt's self-healing properties demonstrate the capability to partially or even fully restore the damage caused by external loads, which could be improved using innovative modifying materials. In this study, the impact of nanoclays on asphalt performance grading (PG), complex shear modulus, and self-healing properties are investigated on a laboratory scale. The intrinsic healing phenomenon of the analyzed binders is measured using a two-piece healing test. Prepared by high shear mixing, the modified binders containing different dosages of two types of organo-modified montmorillonites were evaluated in this paper. In addition to the Superpave PG, the dispersion method's effectiveness was analyzed using a scanning electron microscope. This study indicates that nanoclays improve the high-temperature performance grade of the binder, while they do not hinder the low-temperature performance. Finally, nanoclay-modified binders showed higher shear strength and improved self-healing properties compared to the unmodified binder.