Modeling toughening mechanisms in concrete using multiscale phase field approach

Understanding crack propagation in concrete across different length scales is essential for capturing the intricate failure mechanisms that arise from its highly heterogeneous structure.However, fracture simulations in concrete often have significant computational costs and implementation difficulties.Phase-field models address these challenges by capturing crack phenomena, such as nucleation and propagation while maintaining easiness in implementation.Despite the advantages of phase-field models, their application to fracture analysis of concrete at multiple length scales is limited.Existing phase field models often face substantial computational costs while accounting for material heterogeneity.To address these challenges, a multiscale phase-field fracture study is presented in this work.The focus of the study is to model heterogeneity while maintaining computational efficiency.The first part of this work focuses on generating the meso-scale structure of concrete.This includes considering meso-scale features such as aggregate volume fraction, the interfacial transition zone, and air voids.The second part addresses formulating the multiscale phase-field fracture problem.A three-point bending test is conducted to investigate the fracture phenomena in detail.meso-scale crack toughening mechanisms, such as aggregate bridging and crack deflection, were observed in the model.The fracture energy and tensile strength values are investigated in detail.Finally, the accuracy of the presented model is evaluated by comparing the load-displacement data with experimental results.The findings of this study provide valuable insights for developing more efficient and scalable phase field modelling approaches for fracture phenomena in concrete.