Impact of low-density polyethylene (LDPE) waste on the physico-mechanical and durability behavior of lime-stabilized adobe bricks

Earth-based construction techniques, such as adobe, are valued for their low cost and reduced environmental impact. However, their limited mechanical strength and poor water resistance reduce their overall durability. This study investigates the improvement of adobe bricks through the addition of lime and low-density polyethylene (LDPE) plastic waste derived from greenhouse cleaning activities, in varying proportions (2–6%) and fiber lengths (10–30 mm). The research aims to evaluate the physical, mechanical, and durability characteristics of the modified earth blocks. The results show a reduction of 23.57% in density, 17.95% in ultrasonic pulse velocity, and 37.80% in compressive strength. While the lower compressive strength reflects a mechanical limitation, the decrease in density could be beneficial for lightweight applications or for improving the thermal and acoustic insulation of walls. Conversely, notable improvements were recorded in tensile strength and abrasion resistance, which increased by 71.42% and 90.47%, respectively. Despite these benefits, the mixtures exhibited slightly higher water absorption and swelling, indicating increased sensitivity to moisture. Nevertheless, the reduced mass loss after wetting-drying cycles highlights an overall improvement in the long-term durability of the material.