EVALUATING THE PERFORMANCE OF LIGHTWEIGHT CONCRETE WITH POLYETHYLENE TEREPHTHALATE WASTE

Abstract

Concrete is the most widely utilized building material in civil engineering structures, with its normal variant consisting of natural coarse aggregates, making it heavy and susceptible to seismic effects. To address these issues and promote sustainability, lightweight concrete has emerged as a viable alternative. Lightweight concrete not only reduces the dead load of buildings, leading to cost savings and increased flexibility but also improves seismic response, enables longer spans, and reduces the ratio of reinforcement to foundation materials. However, the production of normal concrete using natural aggregates poses significant environmental concerns and depletes precious natural resources. To mitigate these impacts and ensure ecosystem preservation for future generations, alternative materials are sought. This study explores the use of processed plastic waste, particularly polyethylene terephthalate (PET) aggregates, as a replacement for coarse aggregates in lightweight concrete production. By recycling plastic waste into lightweight aggregates, the environmental burden of plastic disposal is reduced, offering a sustainable waste management solution. The researchers employed PET plastic waste collected from used bottles, heated it to a liquid state, poured it into molds, and subsequently crushed it to obtain coarse aggregates. These PET aggregates were incorporated into the concrete mix design, comprising 25%, 50%, and 100% of the volume of coarse aggregates. Various mechanical and physical tests were conducted on the hardened lightweight concrete to assess its performance. Compressive strength, split tensile strength, water absorption, rebound hammer, and ultrasonic pulse velocity tests were carried out to evaluate the material's suitability for structural applications. Previous studies on the use of recycled waste plastics in concrete were also discussed for validation purposes. The results demonstrated that PET aggregate incorporation led to changes in the concrete's properties, with variations in compressive strength and split tensile strength observed based on the percentage of PET aggregate used and the water-cement ratio. The concrete's water absorption and other characteristics were also affected by the presence of PET aggregates. These findings suggest that PET waste can be effectively utilized to produce lightweight concrete, paving the way for eco-friendly construction practices that minimize environmental impact.