<p>Polyethylene terephthalate fibers (PTF) and high-density polyethylene fibers (HDPF) are plastic waste fibers produced from one-time usage of beverage bottles and other packaging materials. The addition of such fibers can potentially reduce the brittleness and help in avoiding the sudden failure of concrete. This study investigates the effect of PTF and HDPF on the fresh and hardened properties of OPC (Ordinary Portland Cement) based concrete. It was found that the addition of PTF and HDPF in the mixes reduced the workability by approximately 60% and 34%, respectively, as compared to normal concrete (NC). The compressive strength of PTF and HDPF also decreased by approximately 10% and 4%, compared to that of the NC mix. On the other hand, the splitting-tensile strength of PTF and HDPF mixes were improved by approximately 17% and 25%, respectively. Similarly, the flexural strength of PTF and HPDF increased by approximately 16.5% and 24%, respectively. The life cycle assessment of fiber-reinforced mixes showed that the normalized global warming potential (GWP) with respect to splitting-tensile strength was approximately 15% and 20% lower for PTF and HDPF mixes, respectively, as compared to the NC mix. Moreover, the normalized GWP values with respect to flexural strength were approximately 14.8% and 19.8% less for PTF and HDPF mixes, respectively, which depicts that PTF and HDPF can be utilized to produce sustainable concrete mixes.</p>