Confinement and Tension Stiffening Effects in High Performance Self-consolidated Hybrid Fiber Reinforced Concrete Composites

Confinement and tension stiffening effects were studied on self-consolidating, hybrid fiber reinforced concrete (SC-HyFRC) composites and compared to plain self consolidated concrete (SCC) specimens without fibers. The SC-HyFRC composites consist of both steel macrofibers and PVA microfibers with a total fiber volume fraction of 0.015. Cylindrical specimens were confined by continuous steel spirals with transverse reinforcement ratios ranging from 0.32%-1.91% and tested in uniaxial compression. The SC-HyFRC composites despite 2-3 times smaller transverse reinforcing ratios exhibit similar ductility and softening behavior compared to the plain SCC specimens. The effect of SC-HyFRC composites on tension stiffening behavior was investigated using axially reinforced dogbone specimens. The reinforced SC-HyFRC revealed tension stiffening and carried tension to strains far exceeding the yield strain of the reinforcing steel.