Investigation of plastic-sand paving blocks: A sustainable solution using recycled plastic waste

Abstract

This study investigated the feasibility of using recycled plastic waste in the production of plastic-sand paving blocks as a sustainable construction material. Six mix ratios were formulated, varying the plastic waste content from 10 % to 60 % by weight. Physical and mechanical properties, including water absorption, bulk density, and compressive strength, were analyzed. The results indicate that water absorption decreases with higher plastic content, with PSP-R10 (10 % plastic, 90 % sand) exhibiting the highest absorption (8.6 %), while PSP-R60 (60 % plastic, 40 % sand) had the lowest (0.4 %), confirming the hydrophobic nature of plastic. Bulk density varied across the mixes, with the highest density recorded at 1070 kg/m³ for PSP-R50, whereas PSP-R60 showed the lowest density (734 kg/m³) due to excessive plastic reducing compactness. Compressive strength peaked at 74.91 MPa for PSP-R40 (40 % plastic, 60 % sand), demonstrating an optimal balance between strength and flexibility. However, excessive plastic content reduced strength, with PSP-R60 dropping to 27.24 MPa. These findings highlight that a 40 % plastic-to-60 % sand ratio offers the best performance, making plastic-sand paving blocks a promising alternative to conventional materials, contributing to sustainable waste management and eco-friendly construction.