Tensile behavior of strain-hardening cementitious composites after self-healing based on a novel fiber-bridging model considering preloading and reloading

The self-healing of strain-hardening cementitious composites (SHCCs) causes the recovery of the debonded fiber-to-matrix interface by the products of autogenous healing (mainly calcium carbonates). The recovery of chemical bond Gd has been detected in the reactive magnesia cement (RMC)-based SHCC (SHMC), and the recovery of frictional bond τ0 has been detected in both SHMCs and normal SHCCs. While these phenomena can significantly alter the fiber-bridging σ-w relationship in SHCCs, they have not been quantified in any existing analytical models. In this work, we present a new fiber-bridging model that captures the effect of self-healing of RMC-based SHCC. On the single-fiber level, the debonding and slip-hardening of the fiber-to-matrix interface induced by a tensile preloading as well as the recovery of the interface properties by self-healing are coherently quantified in a clear kinetic process. On the fiber-bridging level, the tensile stress vs. crack width curve is formed by summing individual fibers’ tensile load vs. displacement relationship. The modeling results can well capture the fiber-bridging behavior of the self-healed SHCC specimens. Further, a parametric study is conducted to investigate the tensile behavior of SHCC after self-healing. The effects of preloading levels, recovered τ0, and fiber strength are discussed.