Physico-mechanical properties of sand-plastic interlocking paving brick

Interlocking paving bricks were produced with plastic wastes and sand using heating technique without other cementing or binding agent and water. Waste single-use plastics - polyethylene terephthalate (PET) bottles and low density polyethylene (LDPE) sachet water films used respectively were sourced from dump site, washed, air dried, melted and mixed with sand of not more than 2 mm particle size to produce interlocking paving brick (IPB). Sand-plastic mix ratios of 1:1, 1:3 and 3:1 and metal mould of 190 x 90 x 90 mm dimension were used. The compressive strength, flexural tensile strength, abrasion and water-absorption test results showed that IPB from LDPE-sand composite has better mechanical performance than IPB from PET-sand composite for all the mix ratios. The IPB from LDPE-sand composite of 3:1 mix ratio had a compressive strength of 31.11 N/mm(2) and water absorption of 0.33% of its dry weight whereas its PET counterpart had compressive strength of 13.1 N/mm(2) and water absorption of 0.5%. Scanning electron microscope (SEM) and abrasion results also showed that LDPE had better compatibility with sand particles. Waste single-use plastics can be used to produce high quality interlocking paving brick without cement and water and as well reduce the menace of waste PET bottles and LDPE films in our environment.