In order to explore rut deformation characteristics of airport SMA (stone mastic asphalt) under overload, and provide data support for asphalt mixture of mesoscopic models establishing, the angle changes of aggregates in high temperature deformation process of airport SMA asphalt mixture was studied. Angle changes of aggregates in asphalt mixture under high temperature and high load was studied by the method of coring from rutting specimens. 3D digital images of asphalt mixture before and after the rolling was recorded and reconstructed based on X ray CT technology. 2D images along and vertical to the wheel track were extracted from digital specimens. MATLAB image batch processing procedure was taken to obtain binary images. Angles of aggregates were calculated statistically. Results show that the cumulative distribution of asphalt mixture aggregate angle obeys to three parameters Weibull distribution. Angles of aggregates are most in 0°20° intervals. After rolling, aggregate angles along the direction of the wheel track keep increasing in 0°20° interval, aggregate angles vertical to the direction of the wheel track keep increasing in 40°60° range. The angle changes of aggregates along the wheel track have linear relationship with rut deformation. SMA with 70# asphalt is more likely to deflect than SBS modified asphalt SMA mixture.
