Shear Behaviors of Reinforced Ultrahigh Toughness Cementitious Composite Slender Beams with Stirrups

Abstract

This paper presented the investigation on shear behaviors of reinforced ultrahigh toughness cementitious composite (RUHTCC) slender beams with stirrups under center-point loading, where UHTCC possessed the tensile strain-hardening and multiple-cracking characteristics. Eight RUHTCC beams with four different web reinforcement ratios, as well as two reinforced concrete (RC) counterparts, were tested. The experimental results revealed that the use of slight web reinforcement can transform the brittle shear behavior to ductile flexure-shear behavior for RUHTCC beams with about 3.25% longitudinal reinforcement ratio, whereas the flexural failure was obtained when the stirrup ratio was increased up to 0.55% even for the beam with balance reinforcement ratio. Compared to the RUHTCC beam without a stirrup, the ultimate shear strength of RUHTCC beam with a stirrup was slightly enhanced. The shear contribution of UHTCC itself reduced with the increase in the web reinforcement ratio due to the restriction of stirrups. The multiple diagonal cracking and stable crack propagation behavior were presented in RUHTCC beams with and without stirrups, but the number and total opening of diagonal cracks decreased with the increase in stirrup ratio. An empirical equation for predicting the shear resistance of RUHTCC beams with stirrups was proposed based on the shear contribution from both UHTCC and stirrups.