Geocell-Reinforced Crushed Stone Base for Low-Volume Roads

Crushed stone bases are widely used for low-volume roads. However, shear strength of the crushed stone materials can be vastly improved by confining the material in geocellular confinement systems or geocells. Geocells are 3-dimensional honeycomb-like structures. The objective of this study was to test a geocell design with crushed stone (AB-3) in-fill and a thin hot-mix asphalt (HMA) surface layer under real world traffic. A 50-mm HMA pavement test section over a 100-mm thick AB-3 geocell-reinforced base and a 300-mm thick unreinforced AB-3 base were constructed at the Civil Infrastructure System Laboratory (CISL) of Kansas State University (KSU). The sections were instrumented to measure the strains at the bottom of the HMA layer and stresses on top of the subgrade. The unreinforced section was loaded with 50,000 repetitions of an 80-kN single axle load. The reinforced section was loaded with 70,000 repetitions. The calculated and measured responses show, in the reinforced section, stresses on top of the subgrade exceeded the unconfined compressive strength of the soil. It is recommended that the geocell depth be increased along with the thickness of the HMA layer for paved low-volume roads.