Evaluation of predicted pavement fatigue life based on surface profiles and asphalt mixture types

The objective of this study is to evaluate pavement fatigue of both the 12.5 mm+PG58-22 and 12.5 mm+PG64-22 asphalt mixtures by evaluation of the pavement damage index, which is calculated based on the simulated dynamic load and the fracture parameter. The pavement damage index is the change in the pavement fatigue life between a target profile and an as-built profile. To achieve the objective, the dynamic load was simulated based on the pavement surface profile, vehicle speed, and vehicle suspension. The dynamic load increases when the surface profile is rougher, while the incensement of the dynamic load on rougher pavements is accentuated when the speed is higher. For the two asphalt mixtures, the coefficient of variance of the simulated dynamic load and the fracture parameter, which is calculated from the slope of the linear portion of the creep compliance, are used to calculate the pavement damage index. The pavement damage index increases as both the variance of the dynamic load and the confidence level increase. At lower temperatures, the value of n increases. This result indicates that, as the temperature decreases, a larger reduction in the fatigue life of the pavement is expected for the same pavement surface profiles. The 12.5 mm+PG64-22 asphalt mixture has a larger reduction in the pavement fatigue life than the 12.5 mm+PG58-22 asphalt mixture.