A new approach for measurement of the fracture toughness using the edge cracked semi-cylinder disk (ECSD) concrete specimens

Abstract

In this paper, a new approach for measurement of the fracture toughness of concrete using the edge cracked semi-cylinder disk (ECSD) specimens has been rendered. The critical stress intensity factor (fracture toughness) of concretes was determined by using the edge cracked semi-cylinder disk (ECSCD) type specimens. The normalized Mode I stress intensity factor of concrete was measured and estimated through a new formula. The versatile finite element method (FEM) was used to derive this appropriate formula and the Mode I fracture toughness of the specimens determined with a reasonable accuracy. In the laboratory, the notched Brazilian disks (NBD) were tested to evaluate the accuracy of the ECSCD method. A discrete element analysis of the ECSCD tests was also carried out to numerically simulate these experiments and validate the accuracy of the fracture toughness values. Finally, very good agreements gained by comparing the crack extension patterns obtained from the experimental tests with the numerical simulations’ results. However, the toughness values obtained through ECSCD experiments were lower than those measured from the NBD tests. This is due to the smooth distribution of tensile stress around the notch in the ECSCD concrete specimens.