The air void content within bituminous materials is a critical factor in determining the quality and performance of paved roads. An excessively high air void content can lead to several detrimental effects. Primarily, it creates pathways for air and water intrusion, compromising the pavement’s structural integrity. Additionally, high air void content accelerates binder hardening, causing premature embrittlement and reducing the pavement’s lifespan. Furthermore, it can result in uneven compaction under traffic loads, leading to the formation of ruts and grooves along wheel paths.
Conversely, maintaining a minimum air void content is essential for stability during compaction and to accommodate the bitumen’s flow during long-term consolidation under traffic. As suggested by the National Association of Australian State Road Authorities (1968), a sufficient amount of air voids is necessary to allow for binder expansion in warmer temperatures and compaction under traffic loads. Failure to provide adequate air voids can result in bleeding, instability, and increased susceptibility to deformation under heavy loads.
In essence, achieving the optimal air void content in bituminous materials is a delicate balancing act. It requires careful consideration of factors such as material properties, traffic conditions, and climate to ensure a durable and long-lasting pavement.