Numerical Simulation of Tensile Failure of Concrete in Direct, Flexural, Double Punch Tensile and Ring Tests.

The present study considers the tensile strength of concrete samples in direct, flexural, double punch and ring tests using both of the experimental tests and numerical simulation (particle flow code 2D). It determined that which one of indirect tensile strength is close to direct tensile strength. Initially calibration of PFC was undertaken with respect to the data obtained from Brazilian laboratory tests to ensure the conformity of the simulated numerical models response. Furthermore, validation of the simulated models in four introduced tests was also cross checked with the results from experimental tests. By using numerical testing, the failure process was visually observed and failure patterns were watched to be reasonable in accordance with experimental results. Discrete element simulations demonstrated that the macro fractures in models are caused by microscopic tensile breakages on large numbers of bonded discs. Tensile strength of concrete in direct test was less than other tests results. Tensile strength resulted from punch test was close to direct test results. So punch test can be a proper test for determination of tensile strength of concrete in absence of direct test. Other advantages shown by punch tests are: (1) the punch test need less sample size compared with other tests, (2) less material is need for sample preparation, (3) sample preparation is easy and (4) the use of a simple conventional compression press controlled by displacement compared with complicate device in other tests. [ABSTRACT FROM AUTHOR]