Experimental Laboratory On Low-Density Polyethylene (LDPE) Waste Modified Concrete For Pavement Applications

Abstract

Plastic waste disposal and depletion of natural construction resources create parallel challenges for sustainable pavement engineering. This experimental study evaluates M30 concrete in which shredded low-density polyethylene (LDPE)/polyethylene carry-bag waste is used as a partial replacement for fine aggregate. The detailed experimental series reported in the project used replacement levels of 0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% by weight of fine aggregate. The reference mix contained 380 kg/m³ cement, 171 L/m³ water, 672 kg/m³ fine aggregate, 1206 kg/m³ coarse aggregate, and a water-cement ratio of 0.45. Workability was assessed by slump testing, while hardened performance was evaluated using compressive and splitting tensile strength tests at 7, 14, and 28 days; the report also discusses flexural behaviour and water absorption qualitatively. Compressive strength decreased as plastic content increased: the 28-day value fell from 25.96 N/mm² for the control mix to 20.30 N/mm² at 1.0% replacement. In contrast, 28-day splitting tensile strength increased from 4.12 N/mm² for the control to a maximum of 5.57 N/mm² at 0.8%, before decreasing to 5.12 N/mm² at 1.0%. The report further indicates decreasing slump with plastic content and reduced water absorption. The findings show that low replacement levels can provide a useful balance between waste utilization, crack resistance, and pavement-oriented performance, although excessive replacement reduces compressive capacity.