Enhancing concrete performance with geogrid confinement and fiber reinforcement: an experimental study

ABSTRACT This study investigates the impact of internal geogrid confinement combined with fiber reinforcement on the axial behavior of concrete stub columns. Twenty small-scale circular stub column specimens were prepared, incorporating variations in the number of geogrid layers (one, two, and three) and fiber types (steel and polyvinyl alcohol). Results showed that geogrid confinement enhanced the axial load capacity, with double and triple layers improving the load by 10% and 8%, respectively, compared to unconfined specimens. Incorporating fibers further elevated performance, with PVA fibers yielding higher axial strength than steel fibers. Samples reinforced with geogrid and steel fibers exhibited superior fracture energy absorption, particularly in specimens with triple geogrid layers. Both geogrid and fiber-reinforced specimens demonstrated markedly improved load-deformation behavior and higher ductility indices. While geogrid confinement did not substantially increase the ultimate load capacity, it significantly enhanced ductility and energy absorption, suggesting that geogrids present a promising alternative to conventional confinement methods. Future work should focus on comparing uniaxial and biaxial geogrid effects and assessing performance under aggressive environmental conditions.