The Effects of Nano-silica Addition on the Physical Properties of Polyethylene-Modified Asphalt Binder and the Mechanical Properties and Durability of Asphalt Mixtures

The effects of different dosages of nano-silica on the properties of high-density polyethylene (HDPE)- and low-density polyethylene (LDPE)-modified asphalt binders and mixtures were investigated. Penetration grade, softening point, ductility, and elastic recovery of the modified binders, as well as Marshall properties, indirect tensile strength (ITS), moisture damage, and raveling resistance of the mixtures were evaluated. Polymer modification decreased ductility and penetration grade and increased softening point, with a greater effect of HDPE than LDPE. Softening point increased and penetration grade decreased with raising the nano-silica content, with a greater effect of nano-silica on the HDPE-modified binder. The elastic recovery of asphalt binder was improved with polymer modification and the increase of nano-silica content with more elastic recovery for LDPE-modified asphalt. The Marshall properties and ITS of the asphalt mixtures were improved by polymer modification and raising the nano-silica content, with a higher ITS for HDPE-modified mixtures. Furthermore, polymer-modified mixtures have higher moisture damage and raveling resistance than the control mixture, and nano-silica addition improved the moisture damage resistance and negatively impacted the raveling resistance of the mixtures.