Mahmoud Malakouti Olounabadi

This experimental study investigates the compressive behavior of cylindrical concrete specimens internally confined with Polyethylene Fiber Geogrid Mesh (PFGM). A total of 60 specimens were prepared using two concrete cover thicknesses (10 and 20 mm), three PFGM confinement levels (1, 1.5 and 2 layers), and three curing ages (7, 14 and 28 days). The main scientific contribution is the experimental quantification of how an embedded polymeric geogrid modifies the post peak response of concrete, especially ductility, energy absorption and crack propagation, while causing only limited changes in compressive strength. The results indicate that PFGM confinement changes compressive strength by approximately +/-5% on average, but markedly improves deformation capacity. Energy absorption increased by about 90%, ductility by about 50%, and the strain corresponding to maximum stress by about 30%. The embedded mesh also delayed brittle failure by limiting surface crack propagation toward the concrete core and reducing concrete fragmentation after peak stress. These findings show that PFGM can serve as an effective secondary reinforcement for improving ductility, crack control and post peak integrity in concrete members.