Abstract
Asphalt mixtures for airport pavement surfacing have high performance requirements and the air void content is critical to that mixture performance. The traditional Australian specification for airport asphalt set a target air voids content of 4.0%, when measured using an airport-specific and aggregate density-based method. However, with the transition to performance-related specifications, a standard density method was adopted, which uses measured binder absorption when determining mixture density. The two methods resulted in air void content differences up to 3%, which was unacceptable. This research determined the two air voids contents for 27 diverse dense graded 14 mm sized airport asphalt mixtures. Based on analysis of the fundamental differences between the two test methods, a corrector was determined, resulting in significant improvement in the relationship between two test method values. It was also found that the historical test method was fundamentally flawed. Consequently, it was recommended that the historical airport-specific test method be discontinued, in favor of the contemporary standard test method, and that the target air void content in the airport asphalt specification be reduced from 4.0 to 3.5%.