Influence of Recycled Expanded Polystyrene for Sustainable Structural Concrete

Polystyrene represents a substantial problem for the environment, as it is not properly recycled. Hence, this work seeks to demonstrate that concrete in which recycled expanded polystyrene (EPS) replaces a portion of the fine aggregate maintains adequate physical and mechanical characteristics while improving its economic and environmental sustainability. This fact is proven by evaluating concrete samples from standardized tests to determine their characteristics, as well as by implementing life-cycle assessment (LCA) and life-cycle cost analysis (LCCA). Results show that with a replacement of a 100% bulk ratio of EPS instead of fine aggregate, concrete workability, density, and compressive strength decrease up to 50% (2648 N/cm² [3840 psi] concrete), 15% (2942 N/cm² [4267 psi] concrete), and 29% (2354 N/cm² [3414 psi] concrete), respectively, with regard to conventional concrete properties. In addition, EPS generates up to 4.2% of abrasive wear on its surface, according to 2648 N/cm² (3840 psi) concrete with a replacement of 100% of EPS. Otherwise, a good decrease in temperature transfer up to 7°C (12.6°F) is reached in 2354 N/cm² (3414 psi) concrete with a replacement of 100% of EPS. Furthermore, it reduces 15% of CO₂ emissions and saves 16% in energy consumption with a minimal 7% increase in costs based on 2942 N/cm² (4267 psi) concrete with a replacement of 88.2% of EPS. Finally, using a multi-criteria analysis, the optimum percentage of EPS in a 2648 N/cm² (3840 psi) concrete is as high as 87%.