A Review Study of The Effect of Air Voids on Asphalt Pavement Life

Roadways play a main role in the development of the countries and societies by providing the essential links between the different parts of the country, to facilitate the transport of goods and movement of people. Compaction is one of the most critical factors associated with the performance of asphalt pavements. When the asphalt content is too high, the compact of mixture might too easily, moreover resulting in low air voids. When the asphalt content is too low, the compact of mixture may be stiff a nd difficult to the specified density. Asphalt pavements are constructed with initial air voids of 6-8 % depending on the type of mixture and pavement layer. Asphalt mixtures has high air voids content during constructed, it is expected to reduce and this densification can be considered as a predominant cause of rutting during initial periods of traffic. Due to air voids reduction, the material becomes stiffer leading to increase rut resistance. Such increase could also be contributed due to age hardening of the material. Inadequate compaction is one of the leading causes of early deterioration and failure of these pavements. The purpose of this paper is to review the importance and the effect of air voids on asphalt pavement lifespan. The result indicated poor compaction of the mix will leave a high percentage of air voids making it susceptible to moisture infiltration and cracking. Conversely, over compaction may cause mixes to have very low air voids making it subject to asphalt bleeding in hot weather environments.