Recycling of Agricultural Film Wastes for Use as a Binder in Building Composites

Plastic film, also known as low-density polyethylene (LDPE), poses serious environmental challenges due to mass production, short life cycle, and poor waste management. The main aim of this paper was to examine the suitability of using agricultural waste film as a binder in construction composites instead of the traditional cement slurry. Molten at temperatures of around 120-150 °C wastes was mixed with fine sand and gravel aggregate as filler. Twelve samples consisting of different mixtures were produced-F20, F25, F30, F35, F40, F45, F50, F60, F70, F80, F90, and F100-where a given number indicates the weight ratio of film waste to aggregate used. The composites were subjected to various tests, including volumetric density, compressive strength, and flexural strength. The volumetric density (ρ) of the composites decreased with increasing amounts of waste. Composites containing 100% recyclate (F100) depicted density, ρ = 0.74 g/cm³, was 50.7% lower than for a composite that contained 20% recyclate (F20). The highest soakability was recorded in F20 (2.19%). Subsequently, the absorbency tested in composites decreased with increasing recyclate content. Compression strength (σ_comp) was highest for F40 (σ_comp = 39.46 MPa). In contrast, F20 had the lowest recorded compressive strength value (σ_comp = 11.13 MPa) and was 71.8% lower than F40. F70 had the highest recorded flexural strength value (σ_flex = 27.77 MPa). The other composites showed lower strength for higher amounts of recyclate and the amount of sand. SEM imaging proved that the contact zone between the aggregate grains and the bonding phase of the recycled film was consistent, with no anomalies, cracks, or voids. The results prove that LDPE film waste is suitable for use as a binder in building composites. However, appropriately selecting proportions of the recyclate, sand, and gravel aggregate is crucial to obtain a composite with technical parameters similar to those of cementitious composites.