Study on Failure Criterion and Yield Criterion of Early-Age C20

The early-age concrete properties are the basis for structure nonlinear analyzed under construction structure period. But at present the study on early-age concrete is lagging behind which there is not suitabel theory. This paper takes early-age C20 concrete as an example to analysis the early-age concrete properties. According to the distribution characteristics of early-age C20 concrete experiment data in the octahedral stress space, using section function expression form, by the method of mathematical derivation and linear fitting, the failure criterion and the elastic yield criterion of early-age C20 concrete materials in the octahedral stress space are established. By comparison between failure criterion and elastic yield criterion of C20 concrete, the subsequent yield criterion could be derived based on the non-uniform isotropic strengthening criterion.