The role of plastic waste fibers in the behavior of reinforced concrete beams subjected to low‐velocity impact loads

Abstract Numerous researchers have investigated the effects of extreme loading situations, such as impact and blast, on reinforced concrete (RC) structures to establish safe and effective design techniques. The integrity and safety of sensitive structures, such as nuclear containment facilities, against these loads is a significant public concern. The predominant focus of research in the military sector has been high‐velocity impacts on RC buildings. Nonetheless, there is a distinct necessity for an examination of the response of RC elements subjected to low‐velocity impacts. This study examines the impact load behavior of self‐compacting reinforced concrete (SCRC) beams reinforced with plastic waste fibers (PWFs), as previous research has not addressed this aspect. It focuses on the response of SCRC beams to low‐velocity falling‐weight impacts and compares their performance to that of RC beams devoid of fibers. Self‐compacting fiber‐reinforced concrete (SCFRC) is a specialized concrete that integrates the characteristics of self‐compacting concrete (SCC) with the use of fibers for enhanced reinforcement. Twelve SCRC beams have undergone testing, including a cross‐section measuring 100 mm in width and 150 mm in depth, with a clear span of 1350 mm. Three beams served as reference beams, while the other nine beams incorporated PWFs. The beams were categorized into three primary groups based on the longitudinal reinforcement ratio, approximately equivalent to (𝜌max, 𝜌max < 𝜌 < 𝜌min, and 𝜌min), with each group comprising four distinct volumetric ratios of PWFs (0, 0.5, 0.75, and 1) %. The results indicated that incorporating PWFs into the SCC enhances the impact resistance and total maximum reaction force of SCFRC in comparison to reference concrete beams. Moreover, it diminishes the maximum deflection, residual deflection, acceleration, and strain, whereas the quantity of cracks escalates with a reduced crack width. The inclusion of 0.75% PWFs using 𝜌max leads to an increase in the maximum reaction force by up to 30.57% and reduced mid‐span deflection by up to 46%, while the highest impact energy for the reinforced beams was obtained during this study. The rigidity of SCRC beams was notably enhanced, particularly with 0.75% PWFs, and the pronounced impacts of integrating longitudinal steel reinforcement and PWFs are more evident in the first group (𝜌max) compared to the other groups.