This thesis focuses on the compressive behavior of concrete, which is confined by Polyethylene Fiber mesh. Although concrete has a fragile behavior under tensile loads, it is highly resistance when it comes to enduring compressive forces. There are several methods to resolve the tensile weakness in concrete. In recent decades, researchers improved the performance of concrete under tensile forces by enclosing concrete core via FRP. In this regard, geogrids are particularly advantageous since they are not sensitive to corrosion. On the other hand, FRP geogrid is optimized to perform as a high resistant material, which is lightweight and easy to be produced. Consequently, they not only improve the performance of structural members, but also increase the efficiency of structure as a whole, that is FRP geogrids have recently become so popular in construction industry. High adaptation to chemical environment and low density of polyethylene fiber make it a suitable material for reinforcing the concrete samples which are investigated in this research. A set of 60 core confined samples are made in laboratory. The produced samples are divided into four levels of confinement (1, 1.5, 2 and 3 layers). The fibers are implemented in 0 and 45 degrees in different samples. In addition, the size of concrete cover is 10 mm in some samples, while others have the size of 20mm. finally, the behavior of samples are compared together at the ages of 7, 14 and 28 days. The applied polyethylene fiber acts in one direction and is able to endure tensile stress up to 60 KN. The stress-strain diagram is recorded for each sample and used as a reliable index to study the energy absorption, the effect of confinement, compressive resistance and ductility. The results show that polyethylene fiber mesh increases ductility, energy absorption and improved softening behavior of concrete, while it causes a minimal reduction in compressive strength. Furthermore, it stops the growth of surface cracks and pr