Exploiting recycled plastic waste as an alternative binder for paving blocks production

The management of solid waste continues to be a major challenge, particularly in the urban agglomeration in low and middle-income countries. One type of solid waste that is of national and global concern is plastic wastes. This study sought to explore the potential of using plastic waste as a binding material for paving blocks production. Concrete paving blocks (cement: quarry dust: sand = 1:1:2) by weight or volume were produced to serve as Control having tested the compressive strength and water absorption properties. Composite paving blocks less in plastic (LP) on a mix ratio of 1:1:2 and high in plastic (HP) on a mix ratio of 1:0.5:1 by weight or volume were also produced and tested in the laboratory for compressive strength at 7, 14, and 21 days curing via water sprinkling and water absorption test were done after the 72 -h of soaking. The study revealed after 21 days old that paving blocks in HP and LP having compressive strengths of 8.53 N/mm2 (water absorption = 0.5%) and 7.31 N/mm2 (water absorption = 2.7%) respectively were higher than the Control value of 6.07 N/mm2 (water absorption = 4.9%). The authors recommended that the paving blocks made from the recycled plastic waste should be used in non-traffic areas such as walkways, footpaths, pedestrian plazas, landscapes, monument premises and in waterlog areas due to their low water absorption property and relatively low compressive strengths compared to global specs thresholds of 5–25% and low-density to moderate concrete strength 0.69–17.24 N/mm2 respectively.