Effect of slip-hardening interface behavior on fiber rupture and crack bridging in fiber-reinforced cementitious composites

A generic crack bridging model for short fiber-reinforced cementitious composites is developed aiming to analytically account for fiber tensile rupture at the pullout stage and two-way fiber pullout induced by both the slip-hardening interface behavior and the chemical bond and fiber tensile rupture at the debonding stage. Explicit solutions to the current model have been given in this paper. The predicted composite bridging-stress versus crack-opening relations as well as concerned composite characteristics such as the tensile strength and mean postfailure crack opening are shown to reasonably agree with the experimental results for a series of polyvinyl alcohol fiber-based engineered cementitious composites. The influence of slip-hardening interface behavior on fiber rupture and crack bridging is clarified by comparing current model with a previous model. It is found that the slip-hardening interface behavior-induced fiber rupture can significantly govern the crack bridging behavior, and it is essential to take this effect into account. A parametric study based on the current model identifies the critical value of the slip-hardening coefficient for the optimal composite properties.