In response to the growing issue of plastic waste resulting from increased consumption, one promising solution is its reuse as a construction material. Plastic waste poses a significant environmental challenge due to its non-biodegradable nature. It is estimated that 91% of produced plastics are not recycled. While some are incinerated—releasing large quantities of CO₂—others are landfilled, requiring between 100 and 1,000 years to decompose. This study investigates the feasibility of incorporating polyethylene terephthalate (PET) plastic bottle waste into concrete. PET bottles were manually cut into fibers measuring approximately 30 mm × 1 mm (±0.5 mm) and incorporated into concrete at varying substitution rates (1%, 1.5%, 2%, 2.5%, and 3% by sand mass). The water-to-cement ratio was kept constant at 0.5 for all mixes. Physical and mechanical tests were conducted on each formulation and compared with a control concrete mix designed at 350 kg/m³. The results indicate that concrete density increases with PET fiber content, while workability (slump) decreases. Both tensile and compressive strengths were generally enhanced by the addition of PET fibers. The optimal mechanical performance was observed at a PET content of 2.5%, yielding a tensile strength of 3.89 MPa at 7 days and 4.54 MPa at 28 days, and a compressive strength of 22.949 MPa at 7 days and 30.033 MPa at 28 days. Compared to the control mix, this represents a compressive strength increase of 28.09% at 7 days and 11.04% at 28 days. Keywords: Fiber-reinforced concrete, PET waste, compressive strength, tensile strength, density.
ASSAGBAVI KOUDZO, DOKO KOUANDETE VALERY, P'KLA ABALO