What effects does aging have on asphalt binder?

Aging has a profound impact on asphalt binder, primarily causing it to experience increased viscosity, hardening, and brittleness. Over time, exposure to environmental factors such as oxygen, ultraviolet light, and temperature fluctuations leads to oxidation and volatilization of the lighter fractions of the binder. As a result, the binder becomes stiffer and less ductile, which can adversely affect the performance of asphalt mixtures.

The increase in viscosity indicates that the binder becomes thicker and less fluid, making it less workable during construction. This hardening of the binder affects its ability to absorb stresses and can lead to cracking or brittle behavior in the pavement, especially under varying temperature conditions. Understanding the effects of aging on asphalt binder is critical for engineers and practitioners when designing pavement structures, as the durability and service life of the asphalt pavement are directly related to the properties of the binder used.