Flexural Capacity of Reinforced Strain-Hardening Cementitious Composite Beams: Experimental Results and Analysis

The results of an experimental investigation of steel-reinforced beams comprising fiber-reinforced strain-hardening cementitious composites are presented. Polyvinyl alcohol fibers were used in the cementitious mix to achieve significant tensile deformation capacity, which contributed significantly to the flexural resistance. A total of 18 specimens were tested under four-point bending with shear span ratios of 2 and 3.5 to ensure flexural failure. The fiber-reinforced composite's behavior in tension was marked by the formation of multiple cracks that resulted in strain-hardening postcracking behavior and sustained tensile strength up to large tensile strain magnitudes. Variables of the experimental program were the amount of tension and compression steel reinforcement, the availability of confinement (stirrups), and the shear span aspect ratio. Test results illustrated the beneficial action of the fibers in the tensile zone of the beam through bridging of cracks and transferring loads, while in the compressive zone of the beams, fibers restrained lateral expansion and led to ductile compressive response. Analytical expressions to estimate the flexural strength of steel-reinforced, strain-hardening cementitious composite beams were also derived and correlated with the experimental results.