Currently, the durability of cement-based composites is primarily influenced by the presence and transport of corrosive fluids. In structural concrete, various factors such as mechanical loads and drying shrinkage can lead to the formation of cracks, which adversely affect its transport properties. While there is some consensus regarding the impact of individual cracks on transportation, our understanding of crack networks remains relatively limited. Furthermore, the maintenance of stress within the concrete can alter its porosity and influence the opening and closing of cracks, thereby affecting its transport properties. Due to limitations in experimental methods, characterizing the geometry of crack networks poses a challenge. However, numerical modeling offers an efficient and practical approach to investigate the impact of cracks, particularly microcracks, on the diffusivity of concrete.