Investigating The Potential of Recycled Steel Fibers in Concrete

Abstract Concrete is a fundamental material in civil engineering, ubiquitous in construction projects due to its low cost and versatility. However, its inherent brittleness makes it susceptible to abrupt failure under tension, despite its high compressive strength. To address this limitation, various reinforcement techniques have been developed, including Fiber-Reinforced Concrete (FRC). FRC integrates randomly dispersed fibers into the concrete matrix to control hairline cracks and enhance mechanical properties. Steel Fiber-Reinforced Concrete (SFRC) is a notable method wherein short steel fibers are added to the mix. These fibers, with lengths ranging from 15 mm to 70 mm and aspect ratios (AR) from 20 to 100, improve impact resistance, flexural strength, and other desirable properties. This study investigates the use of recycled steel fibers in concrete, aiming to develop an eco-friendly and high-performance construction material. Recycled fibers, sourced from scrap yards, smelters, and other facilities, were analyzed for their mechanical behavior in comparison to conventional concrete. Laboratory tests revealed that an optimal dosage of 1–1.5% of recycled steel fibers with an aspect ratio around 75 improves concrete strength. After casting and testing concrete cylinders and beams, it was observed that strength initially increased up to 1.5% fiber dosage but then plateaued or decreased. This reduction in strength beyond 1.5% may be attributed to decreased concrete cohesiveness and disturbance introduced by the recycled steel fibers. Thus, careful consideration of fiber dosage is crucial for optimizing concrete performance.