Exposed to detrimental environmental
factors, such as heat, oxygen,
and ultraviolet (UV) radiation, asphalt materials are prone to hardness
and brittleness, namely, asphalt aging, which leads to deteriorating
asphalt pavement properties and inducing a series of road distress.
Theoretical and experimental studies have demonstrated that nanomaterial
modifiers are a promising solution. This review discusses the application
of single, compounded, and composited nanomaterial modifiers in improving
the aging resistance of asphalt. Results showed that the introduction
of single nanosilica, nanotitanium dioxide, and nanozinc oxide imparts
positive effects on the anti-UV aging properties of asphalt, and single
nanocalcium carbonate, carbon nanotubes, and layered silicates retard
the thermo-oxidative aging rate of asphalt. Moreover, the multi-dimensional
nanomaterial modifiers, a compound of nanometal oxide and layered
silicates, comprehensively enhance the anti-thermo-oxidative and anti-UV
aging properties of base asphalt and polymer-modified asphalt. Additionally,
the composited nanomaterial modifiers could exert synergetic effects
on asphalt properties and be a crucial area for future research. With
the addition of nanomaterial modifiers, the asphalt aging processes
are restrained by arresting volatile components of asphalt and lengthening
the diffusion paths of oxygen molecules into asphalt binders. Another
contribution mainly derives from functional groups against oxygen,
which hinder the occurrences of oxidation reactions of asphalt. Many
factors, such as nanomaterial modifier types, organic modification,
nanomaterial concentration, and mixing methods and parameters, have
influenced the anti-aging properties of nanomaterial-modified asphalt.
In addition, the compatibility between nanomaterial modifiers with
asphalt and nanomaterial dispersion in asphalt and the high costs
involved in using nanomaterial modifiers are critical challenges for
the application of nanomaterials in improving the aging resistance
of asphalt. However, with cooperation between industrial communities
and research institutes, an expanding application scale of nanomaterial-modified
asphalt can be expected.