Utilization of Recycled Materials in Concrete Production: Investigating the Mechanical Properties and Environmental Impact of Recycled Aggregate Concrete (RAC)

Abstract

The growing demand for construction materials, coupled with escalating environmental concerns, has led to an increased focus on utilizing recycled materials in concrete production. This study examines the mechanical properties and environmental impact of Recycled Aggregate Concrete (RAC), produced using recycled materials such as rubble, stone flakes, rubber, and glass, in comparison with conventional Natural Aggregate Concrete (NAC). The research involved testing for key properties, including compressive strength, flexural tensile strength, water absorption, dryinghrinkage, and creep. The results indicated that the incorporation of recycled aggregates generally resulted in reduced mechanical performance, with rubble and rubber-based RAC showing significant reductions in compressive and tensile strengths. Notably, the failure occurred within the recycled aggregates themselves, highlighting potential weaknesses. In contrast, stone flakes and glass-based RAC demonstrated enhanced compressive and flexural strengths. However, all RAC variants exhibited higher water absorption, drying shrinkage, and creep, which presents challenges for their use in high-strength structural applications. From an environmental perspective, RAC provides clear benefits, such as reducing the reliance on natural aggregates and minimizing landfill waste. Additionally, on-site crushing of recycled materials reduces both construction costs and environmental impact. While the mechanical performance of RAC was generally, lower than that of NAC, its use in low- to medium strength applications appears viable. The study suggests that, although RAC offers significant environmental advantages, further optimization of mix designs is needed to enhance the long-term durability and suitability of RAC for more demanding applications.