Impact of Reinforcement Ratio and Loading Type on the Deformation Capacity of High-Performance Fiber-Reinforced Cementitious Composites Reinforced with Mild Steel

High-performance fiber-reinforced cement-based composites (HPFRCCs) reinforced with mild steel have been proposed for use in structural elements to enhance component strength and ductility, increase damage tolerance, and reduce reinforcement congestion. Recent research has shown that HPFRCCs have a high resistance to splitting cracks, which causes reinforcement strains to concentrate when a dominant tensile crack forms, leading to early reinforcement strain hardening and reinforcement fracture. This paper presents the impact of longitudinal reinforcement ratio, ranging from 0.54 to 2.0%, and the influence of monotonic and cyclic loading histories on the deformation capacity of reinforced HPFRCC flexural members subject to three-point and four-point bending. Experimental results show that load cycling can decrease deformation capacity of flexural members by up to 67% when compared to monotonic deformation capacity. The impact of load cycling on deformation capacity is shown to be strongly affected by changes in longitudinal reinforcement ratio. Unlike traditional reinforced concrete, deformation capacity is shown to increase under monotonic and cyclic loading by increasing the reinforcement ratio of a reinforced HPFRCC flexural element. Using observed failure modes and deformation capacities, combined with prior research results on reinforced HPFRCC components, important considerations are provided for the design of reinforced HPFRCC structural elements to ensure sufficient member deformation capacity.