Softening Response of Plain Concrete in Direct Tension

For rational and accurate analysis of concrete structures, it is often desirable to include the post-cracking resistance of concrete. Due to the difficulties of testing concrete in direct uniaxial tension, only limited and often conflicting data are available. In the present investigation a method was developed to obtain reliable load-deformation behavior in tension, including the post-peak softening response. To characterize the softening response, strains at various locations on the specimens, elongations for various gage lengths, and optical measurements of crack widths were made. Seven different mix proportions were used to obtain information on the influence of aggregate size, water-cement ratio, and volume content of aggregates. An analytical expression has been developed to describe the entire tensile response of concrete.