Improving the performance properties of plastic-sand bricks with Kaolin Clay

Abstract This study analyses the performance properties of plastic-sand bricks through experimental work on the use of High-Density Polyethylene (HDPE) and river sand in the first stage using six different sand: plastic ratios (60s:40p; 65s:35p; 70s:30p; 75s:25p; 80s:20p; 85s:15p) and in the second stage the effects of adding 1%, 5%, and 10% of Kaolin Clay. Five different tests were conducted to assess the bricks’ resistance to environmental factors. The key findings indicate that the lowest water absorption rate of 0.39% was achieved with a 60s:40p ratio, attributed to the addition of 10% Kaolin Clay. Scanning Electron Microscopy (SEM) analysis revealed that Kaolin Clay effectively fills voids between particles, enhancing the structural integrity and reducing water absorption of the brick samples. Electrical resistance readings indicated that all plastic-sand brick samples had a resistance of 0.01 ohms, classifying the composite material as an insulator. Contact angle tests demonstrated that all brick samples resisted immediate water absorption, and no alkali deposits were detected. The lowest linear burning rate was observed in the 75s:25p ratio with a 10% addition of Kaolin Clay. Overall, the findings suggest that HDPE plastic waste can be repurposed to produce eco-friendly plastic-sand bricks, significantly mitigating environmental plastic waste. These composite materials show promise for use as bricks, pavers, and other non-load-bearing applications in the construction industry, providing a sustainable alternative to traditional building materials. This research highlights the potential for HDPE based plastic-sand bricks to contribute to a more sustainable construction sector.