Recycling waste polyethylene foam into fired clay bricks: A sustainable solution for lightweight and thermally efficient building materials

Abstract

Recycling polymer waste by incorporating it into building materials offers a sustainable solution to pollution and environmental challenges. This pioneering study explores the use of waste polyethylene foam (WPEF) as an additive in fired clay bricks, examining its impact on physical, thermal, mechanical, and durability properties. Bricks with 0 %–10 % WPEF content were fired at 900°C and 1000°C to assess their performance. Results show that increasing WPEF reduces bulk density significantly—up to 23.3 % at 900°C and 27.5 % at 1000°C. At 10 % WPEF, the density difference between the two temperatures narrows to 2 %, indicating 900°C as a more energy-efficient option. Thermal conductivity improves by up to 69.63 % at 900°C and 75.84 % at 1000°C, achieving a minimum value of 0.190 W/mK. While water absorption stays within limits at WPEF levels up to 7.5 %, it slightly exceeds thresholds at 10 %. Compressive strength decreases with higher WPEF content due to increased porosity, with bricks containing up to 7.5 % WPEF classified as first-class. Higher WPEF levels also reduce freeze-thaw resistance, particularly at 1000°C, due to crack formation. This study highlights WPEF's potential to produce lightweight, thermally efficient, and eco-friendly bricks with optimized WPEF content and firing conditions.