Abstract: Prevention of concrete cracking is a core issue in the construction of momentous hydraulic concrete structures, and establishing an accurate fracture criteria and determining the mechanical parameters of concrete are key to cracking risk evaluation and crack stability analysis of such structures. This paper formulates a new concept of concrete fracture strength, and develops a calculation method based on fracture toughness by combining the traditional strength theory with the fracture mechanics. This method can characterize the effect of initial defects in concrete on its macroscopic crack resistance, and it is verified against the measurements in previous studies. The results show that concrete fracture strength can be used as an intrinsic material property in cracking analysis and thus an innovative method for concrete structure design is provided.

Key words: concrete, initial defects, fracture toughness, fracture strength, cracking analysis