Usage of single use plastics has been rapidly increasing in the recent past and it is challenging to dispose of these plastics safely, since they are non-biodegradable. Especially, Polyethylene Terephthalate (PET) which is widely used in the form of water bottles cannot be easily recycled or reused. On the other hand, construction projects require sustainable materials having good strength, accordingly various studies have been conducted to reuse plastic wastes in the concrete and positive results have been obtained. In this study, the crushed PET bottles are partially substituted with fine aggregates and water hyacinth is added as a bio plasticizer in concrete. The concrete specimens are cast by substituting PET aggregates with the fine aggregates at 2, 4, 6, 8, 10% and water hyacinth is added at 10 & 20% by weight of water. The specimens are tested and it is noted that with the addition of PET aggregates up to 4% the strength of the concrete increases and beyond 4%, strength of the concrete gradually decreases, and addition of water hyacinth enhances the strength of the concrete.