Investigation of size effect and smeared crack models in ordinary and dam concrete fracture tests

Abstract

This study aims to investigate the size effect and smeared crack models in concrete fracture tests, and explore whether such non-linear models can show the effects of size or not. In the present analysis, the fixed smeared crack model (FCM) was developed for cracked concrete specimens of laboratory size under three-point bending and wedge splitting, and the different fracture parameters of the size effect model were evaluated using the data obtained from the laboratory and numerical analysis. According to the analysis, the need for a separate examination of the effects of material properties of ordinary concrete and dam concrete was shown. Besides, even the creation of specific equations for them which was due to the effect of the fracture energy, the effective length of the fracture process zone (FPZ) and the fracture toughness was clearly demonstrated in the size effect and the related numerical equations. It is concluded that the fracture parameters obtained from Bažant’s size effect model and other nonlinear fracture models including the FCM are influenced by the specimen size. The results indicate the relative weakness and decay of this type of the FCM described in this study can be used to better describe the effects of the size, especially when the concepts of the initial and total fracture energy are not considered.