Tailoring strain-hardening cementitious composite repair systems through numerical experimentation

Innovative cement-based repair materials may require different procedures for application in comparison to standard repair requirements. Before their field application, a proper protocol should be established. Apart from laboratory experiments, numerical simulation can be of great use. Herein, a lattice type model is used to simulate fracture performance of fiber reinforced repair material – strain hardening cementations composite (SHCC) and its performance in the repair system. Repair material was first tailored through numerical testing in a single fiber pullout test and a direct tension test. Further on, structural behavior of the repair system and impact of initial defects in the mortar substrate (reflective cracking) was examined. The influence of fiber addition, different simulated substrate roughness and interface properties between new and old material on the performance of the repair system is investigated. Fracture propagation and sequence of crack development obtained by simulation is compared to experimental results. The numerical study gives insight into the benefits of distributed microcracking and high ductility of the fiber reinforced system over localized cracking and inherent brittleness of a non-reinforced repair system. It is envisioned that this approach can be used to tailor the properties of the repair system for specific applications, resulting in more reliable and durable concrete repairs in the future.