Integrating concrete performance life cycle assessment and plastic littering potential for sustainable PET waste management in the Galapagos Islands

Plastic waste management is particularly challenging in ecologically sensitive and geographically isolated regions such as the Galapagos Islands. This study integrates experimental characterization of recycled polyethylene terephthalate (rPET) concrete with Life Cycle Assessment (LCA) and Plastic Littering Potential (PLP) to compare local rPET use with alternative PET waste management pathways under island-specific conditions. Concrete mixtures containing 0%, 5%, 10%, 15%, and 20% rPET as partial coarse aggregate replacement were evaluated. Increasing rPET content progressively affected concrete performance: compressive strength decreased from 29.88 to 18.84 MPa, indirect tensile strength from 3.31 to 2.00 MPa, and slump from 190 to 70 mm. The 5% rPET mixture exhibited the smallest mechanical reduction, retaining 86% of the control compressive strength (25.70 MPa) and the same mean slump (190 mm), although it remained below the 28 MPa target strength. Concrete-production GWP increased from 345.87 to 354.02 kg CO 2 eq./m 3 between 0 and 20% rPET. At the waste management level, GWP was 0.16, 0.08, −0.07, and −2.55 kg CO 2 eq./kg PET waste for landfill, rPET concrete, cement kiln co-processing, and textile recycling, respectively. PLP decreased from 0.95 kg plastic litter/kg PET waste for landfill to 0.15 for rPET concrete and 0.10 for co-processing. The results highlight trade-offs between concrete performance, climate impacts, plastic littering, and logistics, supporting integrated assessment of circular economy strategies for PET waste in island regions.