Discrete modeling of concrete failure and size-effect

Size-effect in concrete and other quasi-brittle materials defines the relation between nominal strength structural size when material fractures. The main cause of size-effect is so-called energetic which results from release stored energy structure into fracture front. In contrast to brittle materials, process zone non-negligible compared size. As a consequence, resulting law non-linear deviates response predicted by linear elastic mechanics. order simulate size-effect, one needs rely on numerical modeling describe formation, development propagation zone. Although number models have been proposed over years, it transpires that correct description accounts for boundary effects varying geometry remains challenging. this study, Lattice Discrete Particle Model (LDPM) investigate dimension fracturing concrete. LDPM simulates at aggregate level has shown superior capabilities simulating complex cracking mechanisms thanks inherent discrete nature model. evaluate provide solid validation LDPM, most complete experimental data set available literature was considered includes three-point bending tests notched unnotched beams. model parameters were first calibrated single beam under mechanical unconfined compression. then used perform blind predictions load-crack mouth opening displacement curves different sizes notch lengths. Splitting test cylinders also predicted. show very good agreement with data. quality quantitatively assessed. addition, discussion dissipated provided. Last but not least, Universal Size-Effect Law Bažant coworkers estimate based