An assessment of the strength and durability characteristics of recycled plastic pavers.

Abstract

The generation of waste is reaching record highs and displays a consistent uptrend over the last decade, and despite high generation rates, landfilling is still the dominant disposal method for waste in South Africa. However, these materials may have potential for reuse in several applications, and industries are considering their viability. One such industry is the construction and engineering industry, which has seen an increase in research into the application of waste materials. This study explores the use of HDPE, PP, and glass waste as an alternative material for making concrete pavers. The study uses local waste materials to assess the density, durability, and mechanical strengths of the resulting paver, called Eco-pavers, and compares them to regular concrete pavers for accuracy. The pavers are made of a 50/50 blend of recycled plastic and glass aggregate, which has not been widely studied as a replacement for cement or stone aggregate. The Eco-pavers demonstrate a low water absorption rate of 0.28%, compared to the 4.5% of concrete pavers. After immersion testing in various chemicals over a 180-day period, the pavers show no signs of degradation either structurally or visually. The Eco-pavers are suitable for use as impermeable pavers, as they did not allow any infiltration during the permeability test. The flexural strength assessment resulted in an average breaking stress of 7.9 MPa, which is greater than the prescribed minimum. However, the pavers' average compressive strength is 12.47 MPa, which is below the minimum criterion of 35 MPa for pavers, and therefore needs improvement. In summary, this study explored the use of recycled plastic and glass waste in manufacturing Eco-pavers as an alternative to traditional concrete pavers. The resulting pavers demonstrated low water absorption, chemical resistance, and impermeability, making them suitable for impermeable applications. However, the compressive strength of the pavers needs improvement. While their short-term use is unlikely to release microplastics, further research is needed to determine their long-term impact.