Deformation capacity and shear strength of fiber-reinforced cement composite flexural members subjected to displacement reversals

The behavior of fiber-reinforced cement composite (FRCC) flexural members under large displacement reversals was experimentally evaluated. Emphasis was placed on estimating the displacement capacity and shear strength of members constructed with strain-hardening FRCC materials. Two types of fibers were used: Ultrahigh molecular weight polyethylene fibers and steel hooked fibers in volume fractions ranging between 1.0 and 2.0%. The primary experimental variables were: (1) fiber type and volume fraction; (2) type of cement-based matrix (concrete or mortar); (3) average shear stress demand at flexural yielding; and (4) shear resistance provided through hoops versus total shear demand. All specimens constructed with a strain-hardening FRCC, with or without web reinforcement, exhibited drift capacities of at least 4.0%. A shear stress level of 0.30 root f'(c) [MPa] represented a lower bound for which no shear failure occurred in the strain-hardening FRCC test specimens, regardless of the member inelastic rotation demand. In addition, buckling of longitudinal reinforcement in the strain-hardening FRCC members without web reinforcement was not observed up to plastic hinge rotations of 4.0%.