Performance Evaluation and Design Methodology for Geocell-Reinforced Unpaved Roads Through Full-Scale Laboratory Accelerated Pavement Testing

A comprehensive full-scale laboratory study was conducted to investigate the reinforcement of base course macadam using geocells to withstand design traffic loading with reduced thickness. The study compared unreinforced and geocell-reinforced water-bound macadam unpaved roads, focusing on the number of load cycles needed to achieve a rut depth of 50 mm. Results demonstrated that the geocell-reinforced model performed significantly better, enduring 3.54 times more load cycles than the unreinforced model. Additionally, vertical stress measurements at the base-subgrade interface showed lower stresses in the geocell-reinforced model, leading to a wider stress distribution angle, which ranged from 42 to 65%. Based on these experimental findings, a design method was developed using the Giroud and Han approach to calculate the base course thickness for both unreinforced and geocell-reinforced unpaved roads. This paper highlights the benefits of geocell reinforcement in pavement design and provides a method to optimize base course thickness.