In recent times, a substantial part of the generated solid waste all over the world are plastic-related waste with wide ranges of serious environmental and public health consequences. This study investigates the beneficial use of recycled high impact polystyrene (HIPS) and low-density polyethylene (LDPE) plastic wastes in cement-based composites for production of high strength lightweight concrete. The HIPS and LDPE plastic wastes were recycled into plastic granules of about 2 mm particle sizes and was used to partially substitute the sand in the concrete mixes at varied percentage levels of 0, 10, 30 and 50% by weight using a mixture proportion of 1:1.5:3 (cement: m-sand: coarse aggregate) at water-cement (w/c) ratio of 0.5 with a target characteristic strength of 30 N/mm2 at 28 days. The material characteristics were defined, and concrete cube samples of size 100 mm were cast and tested in the fresh and hardened state. Test results indicate a decrease in the workability, density and compressive strength as the quantities of the recycled waste plastic granules increases. Implications of these results show the possibility of using recycled plastic granules from both high impact polystyrene and low-density polyethylene plastic wastes at optimum of 10% for producing lightweight-high strength concrete that is closely similar in strength to lightweight concrete produce with conventional materials.
