An accelerated pavement testing (APT) experiment was conducted to evaluate field performance of foamed asphalt-treated reclaimed asphalt pavement (RAP) layers used in a flexible pavement structure under typical southern Louisiana highway conditions. The APT experiment consisted of three full-scale flexible pavement sections with different base layers: a regular good-performing crushed stone base and two foamed asphalt-treated RAP bases containing different RAP percentages. Laboratory test results indicated that the two foamed asphalt RAP materials exhibited the higher potential of moisture susceptibility, had less resilient moduli, and were more prone to permanent deformation than the crushed stone base material considered. The APT results showed that the foamed asphalt base test sections had excellent early performance, but both failed by a suddenly sharp increase in permanent deformation when the APT load level was increased. A shakedown analysis revealed that the foamed asphalt treated RAP base materials could have lower shakedown stress thresholds than that of the crushed stone under a moisture-rich road condition. Finally, forensic investigation indicated that one foamed asphalt base failed mainly due to its severe moisture susceptibility, while the other experienced both mositure and over-asphalting problems.