Plastic Waste as Fine Aggregate for Sand Filler Replacement in Concrete

Since its invention in 1907, plastic has been widely utilized worldwide. As plastics were thrown away after a single use, a severe problem arose, resulting in substantial pollution and contamination of the environment. Plastic bottles accounted for a significant portion of the plastic trash disposal. Plastic bottles are frequently made from waste polyethylene terephthalate (WPET). As a result, PET plastic bottles were employed as a by-product in this experiment since they are light in weight and, more significantly, help decrease trash pollution. The purpose of this study is to investigate the properties of concrete by partially replacing sand with plastic waste as fine aggregates, with the goal of this experiment being to determine the optimum percentage of sand replacement with plastic while maintaining compressive strength or achieving similar strength within the grade used when compared to reference concrete. 7 batches of 6 cubes each have been cast. One batch served as a control, three batches were cast without the addition of superplasticizer, and three more batches were cast with the optimal percentage of PET plastic replacement after the addition of superplasticizer. The subject of this investigation was the compressive strength test using 0%, 5%, 10%, and 15% PET plastic substituted with sand in concrete. After 7 days and 28 days of curing, a compressive strength test was performed. The plastic concrete’s maximum compressive strength was 27.6 MPa, which appears to be somewhat lower than the control sample. When a slight variation in strength is detected, the results are acceptable. The slightly lower strength obtained might be because of plastic's hydrophobic material. Therefore, a superplasticizer was added to improve the workability and compressive strength of the optimal plastic concrete. Naphthalene sulfonate formaldehyde was employed as a superplasticizer. Further research was carried out to understand better the characteristics of partial sand replaced with plastic, with or without a superplasticizer.