Mechanical properties assessment of recycled brick aggregate concrete using demolition waste from century-old masonry buildings in Nepal

This study explores the potential of recycling bricks from dismantled old buildings into brick aggregates and utilizing them as coarse aggregates in recycled brick aggregate concrete. Nepal, being susceptible to seismic events, generates large amounts of construction debris, with bricks being a major portion of this, which is mainly disposed of through landfilling. Additionally, the increasing use of reinforced cement concrete construction has been significant, which poses a toll on natural aggregate resources, resulting in the depletion of finite resources. To address these issues, this study focuses on recycling bricks as coarse aggregates in concrete. An experimental approach was adopted to determine properties of bricks and concrete ingredients, including cement, sand, brick aggregates, and coarse aggregates. The mechanical and physical properties of concrete, that is, compressive, split-tensile, and flexural strengths were studied by replacing natural coarse aggregates with recycled crushed brick aggregates at different percentages (0%, 10%, 20%, 30%, and 100%), denoted as B0%, B10%, B20%, B30% and B100%, respectively. Meanwhile, ultrasonic pulse velocity was performed to determine the quality of recycled brick aggregate concrete. With respect to the control mix (B0%), percentage decrease in compressive strength, tensile strength, and flexural strength for B10% and B100% are 0.72% and 28.26%, 4.68% and 25.16%, and 2.95% and 7.58%, respectively. From the ultrasonic pulse velocity, all mixes except B100% had excellent quality as per Indian Standards. Results highlight that recycled brick aggregate seems suitable up to 30% replacement, considering the strength decrement in compressive and flexural strengths relative to the control mix.