Quantifying geogrid improvements in highway pavements

Geogrids stabilize unbound aggregate layers, leading to the formation of a mechanically stabi-lized layer (MSL). However, there is a lack of data quantifying the degree of local stiffness improvement in the granular base/subbase and the stress reduction on subgrade achieved through geogrid stabilization. This study employed advanced in situ testing and instrumentation to collect and analyze data from three pavement sections, one control and two geogrid-stabilized, constructed during the US-20 reconstruction project in Elkhart, Indiana, USA. The results quantify local stiffness improvements near the geogrids and demonstrate higher resilient mod-ulus and reduced deformation trends in the geogrid-stabilized sections. These findings offer valuable insights for advancing the mechanistic-empirical designs of base course geogrid-stabilized pavements.