Experimental Study on Mechanical and Durability Properties Incorporating Recycled Aggregate and Steel Fiber

The growing need for sustainable construction materials has led to increased interest in recycled aggregate concrete (RAC) reinforced with steel fibres. This study aims to evaluate the feasibility and performance enhancement of recycled total concrete incorporating black steel fibres, specifically low-strength fibres with an aspect ratio of 50. The investigation uses natural coarse and fine aggregates, recycled coarse aggregates, black steel fibres, and a superplasticizer. Natural coarse aggregate is progressively replaced with recycled coarse aggregate at five levels: 0%, 25%, 50%, 75%, and 100%. Additionally, steel fibres are incorporated at fibre volume fractions of 0%, 1%, 1.5%, and 2% to assess their effectiveness in improving mechanical and durability characteristics. The experimental program examines how the combined effects of recycled aggregates and black steel fibres influence the strength, deformation behaviour, and overall structural performance of concrete. Particular emphasis is placed on understanding the contribution of low-strength steel fibres to crack control, toughness, and post-cracking behaviour in RAC. Through comprehensive analysis of various mix combinations, the study aims to identify the optimal fibre content and recycled aggregate replacement level that enhance the performance of concrete while maintaining workability and structural integrity. The findings of this research provide valuable insights into the potential of integrating recycled aggregates with low-strength black steel fibres in sustainable concrete production. The study supports the development of environmentally responsible construction practices by demonstrating the viability of using waste-derived materials and fibre reinforcement to improve the mechanical behaviour of recycled aggregate concrete.