Comparative Field Evaluation of Geogrid-Stabilized Flexible Pavements under Static and Repetitive Loading

Establishing a relationship between reinforcement benefits under static and repetitive loading remains a challenge for evaluating the field performance of geogrid-stabilized flexible pavements. While static plate bearing tests (SPBTs) are commonly employed to assess pavement layer stiffnesses, repetitive plate bearing tests (RPBTs) better represent traffic-induced deformation, and the linkage between the two responses has not been clearly established through field investigations. This study examines the performance of conventional and geogrid-stabilized pavement sections constructed over different subgrade strengths using SPBTs and RPBTs. Pavement sections were designed according to mechanistic-empirical guidelines and constructed in the field to evaluate stiffness and deformation characteristics. Reinforcement benefits from SPBTs were quantified using the layer coefficient ratio (LCR) and the modulus improvement factor (MIF), while repetitive performance was evaluated using the traffic benefit ratio. Static tests showed MIF values ranging from 2.10 for weaker subgrades to 1.72 for stronger subgrades. Repetitive tests showed lower rutting and greater load repetitions in reinforced sections. LCR values obtained from RPBTs were slightly lower than those from SPBTs. An empirical relationship is proposed to link the benefits of reinforcement from static and repetitive tests, providing a practical basis for interpreting repetitive load-based performance from SPBTs results.