Tension stiffening in reinforced high performance fiber reinforced cement-based composites

High Performance Fiber-Reinforced Cement-based Composite (HPFRCC) materials carry tension to strains greater than the yield strain of reinforcing steel and exhibit distributed compression damage with minimal spalling. Characterization of the interaction between the composite and steel reinforcement to large strains (i.e., >0.005) remains largely unknown. Three HPFRCC materials as well as concrete with a single reinforcing bar are tested in a prismatic specimen in uniaxial tension up to fracture of the reinforcement. Multiple cracking of the composite led to uniform bar yielding throughout the specimen and early hardening of the reinforcement at the location of dominant cracks. The reinforcement fractured within the HPFRCC at lower strain levels relative to the reinforced concrete. A modified approach based on planar analysis to estimate flexural strength of reinforced HPFRCC components using tension-stiffening data is proposed.