Strength Values of Cementitious Materials in Bending and Tension Test Methods

Abstract

A value of tensile strength of cement-based materials is required for the design of pavements, for the analysis of concrete dams to prevent thermal cracking and sometimes for the design of prestressed beams. Cementitious materials exhibit a significant variability in their tensile strength, depending on the test method used. The three common test methods are direct tension, three-point bending, and four-point bending, and it is commonly found that bending tests yield higher strengths than direct tension tests. During this investigation, tests were carried out on cement mortar and concrete for each type of test. A two-parameter Weibull model was found to fit each individual set of data well. For both cement mortar and concrete, the Weibull moduli calculated for the test methods were approximately the same. The Weibull modulus is used to relate the values of strength obtained with different test methods, using the Weibull effective volume concept, the predicted results are in remarkably good agreement with the experimental results.