The fractal properties of material, including the fractal aspect of crack surface roughness and the lacunar fractal aspect of pore structure, may have a role in the size effect in concrete, and may affect the fracture energy of material. However, the fractal properties have yet not been experimentally documented for a broad enough scale and the problem has not yet been studied in depth comparable to the statistical and energetic size effects. The main obstacle to the practical consideration of a fractal influence on the size effect is that, if calibrated for one structure geometry, it is not clear how infer the size effect for another geometry. The pros and cons were discussed, e.g., by Carpinteri et al. (1994, 2001) and Bažant and Yavari (2005).