Specimen geometry in uniaxial tension test of concrete

Tension softening behavior is essential to analyze and understand the fracture process of concrete and concrete structures. Many test methods of uniaxial tension for concrete have been investigated for 40 years to obtain tension softening behavior. The test methods were different in specimen geometry, loading process and control of secondary flexure. This study concerns the specimen geometries such as prisms, cylinders and dog-bone types with or without notches. In some types of specimens, we cannot obtain an exact tension softening behavior and tensile strength. However, inappropriate specimens have been adopted even in recent investigations, because of several misunderstandings in the test methods. Such misunderstandings are discussed and clarified referring to experimental evidences, numerical simulations and theoretical considerations. Considering also the ease of specimen handling, it is concluded that a notched prism should be recommended among all the specimen geometries.