Influence of the Width of the Loading Strip in the Brazilian Tensile Test of Concrete and Other Brittle Materials

AbstractDifficulties presented by the direct tensile test of nonhomogeneous, brittle materials were circumvented by the proposal of an indirect tensile test for concrete, known in the literature as the Brazilian test, which found applications in the technology of concrete, rocks, ceramics and other materials. Relationships between the predictions of the Brazilian test and the results of both the direct tensile test and the unconfined compression test have been proposed on the basis of experimental evidence. On the other hand, developments in numerical fracture analysis allowed for the examination of the fracture process in the test, including the consideration of scale and rate effects. The discrete element method was used to determine the nonlinear response of brittle solids and to predict the response of simulated concrete samples subjected to indirect tensile tests. This paper extends this approach to more precisely quantify the role of factors such as the width and stiffness of the strips inserted between the press platens and the sample cylinders. The flexibility of the strip exerts a marginal influence on the result of the test. The predictions of the indirect splitting tensile test would significantly improve by replacing the wood strip (with β=0.1) by a metallic strip with curved lower surface and larger width. A thorough experimental program should be carried out to establish the optimum width for normal concrete and/or other materials or sample sizes.