Mechanical Properties of Plastic Concrete Made Using Recycled Aggregates for Paving Blocks

In developing countries, the management of waste continues to be a major challenge, especially in urban areas. One of the major concerns for today's world is the management of plastic and construction and demolition (C&D) wastes which are increasing with urbanization and population growth. This study aims to explore the possibility of the use of plastic waste as a binder and recycled aggregates obtained from C&D waste to produce concrete paving blocks. The mechanical investigation was carried out to find the optimum content of plastic waste to prepare the plastic concrete. Three different concrete mixes were prepared with plastic contents of 30%, 40%, and 50% by the weight of aggregate. To evaluate the mechanical properties of plastic concrete, compression, flexural, and ultrasonic pulse velocity (UPV) tests were performed on the prepared samples. Cubical specimens of 36 x 40 x 40 mm for compression tests and prismatic specimens of 36 x 40 x 120 mm for flexural tests were cut using a saw from the paving blocks of size 36 x 137 x 290 mm. The results indicated that the strength of plastic concrete increased with the increase in plastic content. The maximum compressive and flexural strength was achieved at 50% plastic content, which was 40.52 MPa and 10.13 MPa, respectively. The compressive and flexural strengths of plastic concrete were compared with the minimum strength requirement specified by various standards specification such as American, Canadian, and Chinese. It was found that plastic concrete with 50% content of plastic waste meets the minimum criteria of mechanical strengths specified in these standards. Presently, many countries of the African continent are facing severe problems of plastic waste. As per the findings of this study, the use of waste plastics in molten form as the only binder in the development of concrete paving blocks could offer a solution for such countries to beneficially manage the plastic waste.