A new approach for measurement of tensile strength of concrete

Tensile strength is one of the important mechanical properties of concrete. Indirect methods have been used up till now for its measurement. These methods though widely accepted, do not furnish the true tensile strength of concrete. In this paper, a compression to tensile load transformer device is developed to determine direct tensile strength of concrete. The cubic concrete samples with dimension of 15*19*6 cm containing internal hole with dimension of 75mm is prepared using the mixture of cement, fine sand and water. This model is subjected to direct tensile loading by special loading device. A series of finite element analysis were performed using FRANC2D to analyse the effect of hole diameter on the stress concentration around the hole and to render a suitable criteria for determination of real tensile strength of concrete. Concurrent with direct tensile test, Brazilian test is performed to compare the results of two methods. Results obtained by this test are quite encouraging and shows that the direct tensile strength is clearly lower than the Brazilian test. The difference between the Brazilian and direct tensile strengths is about 33%.