Heterogeneous fracture toughness of aggregate-reinforced materials via efficient mesoscopic modeling

Accurate assessment of fracture toughness in aggregate-reinforced materials, such as concrete, is essential for predicting failure under various loading conditions. Conventional methods rely on homogeneous fracture parameters, overlooking the critical influence of mesostructural heterogeneity. We present a comprehensive framework to quantify heterogeneous fracture toughness by incorporating aggregate-scale features into finite element models. Realistic mesostructures were used to compute geometry factors and T-stress variations along the crack front, revealing substantial local variability due to aggregate dispersion and spatial randomness. By integrating these results with previously reported critical fracture loads, we determined lower and upper bounds of heterogeneous fracture toughness. Linear equations were developed to convert conventional homogeneous values into corresponding heterogeneous bounds. These findings underscore the role of mesostructure in defining fracture threshold zones. Our approach provides a generalizable methodology for evaluating fracture behavior in concrete, asphalt, and other aggregate-reinforced composites, with implications for design, performance assessment, and durability.