Initial cracking strength and initial fracture toughness from three‐point bending and wedge splitting concrete specimens

In this study, a concept of initial cracking strength of concrete was elaborated. A fracture model and associated methods for determining independent initial cracking strength and initial fracture toughness by the three‐point bending (3‐p‐b) and wedge splitting (WS) concrete specimens are presented. The initial cracking strength and initial fracture toughness can be simultaneously determined using a curve fitting method from the proposed fracture model. All of the initial fracture curves were obtained by the determined concrete materials. The initial loads of the 3‐p‐b and WS specimens were predicted on the basis of the curves with ±15% ranges. Furthermore, the initial cracking strength and the initial fracture toughness of concretes were directly determined by analytical functions. The determined values within ±15% ranges cover most of the initial loads of the 3‐p‐b and WS specimens.