Investigation of the Use and Suitability of Plastic Waste for Molding Interlocking Stones in Port Harcourt

Port Harcourt is known in local parlance as the ‘Garden City’ of Rivers State. This is so tagged because of the overwhelming presence of trees (Green Life) and flowers in the Metropolis. But today, it is different as the streets, gutters, rivers and the environs are littered with all types of plastic waste (MSW). These municipal solid wastes (MSW), are indiscriminately dumped at different locations in the Garden City. Plastics constitute a major component of these wastes; thus, this study was aimed at Investigating the Use and Suitability of plastic waste for molding Interlocking stones in Port Harcourt. In this study, samples of plastic wastes (bottles, cups, plates, spoons, and cellophane bags), were collected randomly at selected locations in Port Harcourt City. The area of study covered GRA Phase 1, 2, and 3, Old GRA, Diobu axis, and Port Harcourt main town. These plastic wastes are (PET-Polyethylene Terephthalate) which after collection were weighed and mixed with fine grains of sand (4 kg). The plastic waste samples of 5, 10 and 15 kg were used to mix with fine grains of sand of 4 kg. The mixture was heated under very high temperatures and melted to form a homogeneous mixture. The resultant homogeneous mixture was then poured into different molds of the same sizes (1.32 x10^-3 M³). In another reaction, fine grain of sand of 4 kg was mixed with cement of 5, 10 and 15 kg respectively. The mixtures were poured into molds of the same sizes (1.32 x10^-3 M³). The strengths of the two different interlocking stones (paver) were measured and compared to confirm which one of them has a better compressive strength for 7, 14 & 28 days. A total of fifty-four (54) molds were used of which twenty-seven were made from plastic waste and the other twenty-seven from cement. The compressive strength of Interlocks made from the two substances were measured and compared. The result showed the compressive strength of Interlocks made from 5, 10 and 15 kg of plastic wastes and 4 kg of sand for 7, 14, and 28 days being comparable to that of cement. The t-test showed that there is no significant difference between the strength of mold made by cement and that of plastic waste. This implies that Plastic Wastes can act as a suitable alternative material to cement for the making of interlocking stones as it has excellent binding properties like cement. This study recommends proper management and disposal of wastes to reduce environmental degradation.