Recycled expanded polystyrene (EPS) as an eco-friendly alternative for sand in rendering mortars: Fid-Bau Portal

Recycled expanded polystyrene (EPS) as an eco-friendly alternative for sand in rendering mortars

Leão, Lais Sousa / Spini, Gabriel Pandolfi / de França, Marylinda Santos / Costa, Eliane Betânia Carvalho

Abstract This study assesses the viability of recycled expanded polystyrene (EPS) as an eco-friendly alternative for partially replacing sand in rendering mortars. Three mortars formulations were tested: one using 100% natural sand as a reference, and two with 30% volumetric substitution of natural sand by EPS (either virgin or recycled particles) in the total mortar volume. Two distinct mixing methods were employed for mortars incorporating EPS particles. The rheological behavior was assessed using a squeeze-flow test, and after 28 days, mechanical properties were evaluated, including compressive and flexural strength, and dynamic elastic modulus. Microstructural analysis via SEM-EDS and capillary water absorption tests were performed, along with an investigation into adhesive strength between concrete substrate and mortar. Mortars with EPS particles exhibited improved fluidity, with an initial mixing step enhancing particle homogenization. Notably, recycled EPS flakes outperformed virgin EPS beads in mechanical properties, particularly with mixing method B. Moreover, water absorption rates varied, and adhesive strength remained comparable to the reference mortar.

Highlights • Partially replacing sand for EPS particles improves mortar flowability. • Recycled EPS flakes outperformed virgin EPS beads in mechanical properties. • Mortars with recycled EPS flakes exhibited strong adhesive strength. • Recycled EPS flakes offer a sustainable solution for reducing sand extraction.