Experimental investigation of the mechanical behavior of concrete made with recycled PET fibers for structural applications

According to increasing the use of PET products, the present study aimed to the use of PET fibers in the concrete industries. Moreover, the behavior of normal concrete contained recycled fibers is not studied and the guidelines aren’t published yet. The aim of this study was to determine the effect of polyethylene terephthalate fibers on the mechanical properties of hardened concrete. Fibers were used in three volumetric percentages of 0.15%, 0.30%, and 0.45% with the lengths of 1, 2, and 3 centimeters, separately. So, 10 combinations of specimens including the control specimen and 9 combinations of PET fiber reinforced concrete were made. All mixtures were examined for compressive strength, tensile strength, flexural strength, shrinkage, durability, and impact loading.The results showed that by adding the PET fibers, the compressive strength, the bending strength, and energy absorption increase 5 to 18 percent, 6 to 30 percent, and 30 to 156 percent, respectively. However, no noticeable change was observed in tensile strength , while even a reduction in tensile strength is monitored. The impact strength of the fiber concrete was increased two to seven times in comparison with the control concrete. By comparing the experimental results it was determined that the combinations that contained 2 cm fibers with 0.45% volume had the best performance compared with the other mixtures.