BIMATERIAL BRAZILIAN SPECIMEN FOR DETERMINING INTERFACIAL FRACTURE-TOUGHNESS

The test specimen proposed in this study, named the bimaterial Brazili an specimen, is a cylindrical specimen consisting of two dissimilar ma terials with a cross-section through a diameter of the cylinder as the ir interface. Stress intensity factors for the tip of the crack in the interface were calibrated with the finite element method for several different moduli combinations and loading directions. Specimens consis ting of mortar and rock were prepared and tested to simulate the morta r-aggregate interface in concrete. Test results show that apparent mor tar-limestone interfacial fracture toughness increases with the phase angle and also that specimen size has significant effects on the appar ent interfacial toughness. The possibility of investigating the effect of specimen size in the interfacial toughness is particularly importa nt in the study of a heterogeneous medium (such as concrete) since the size of inclusions (such as aggregate in concrete) is known to affect the strength of the medium. (C) 1997 Elsevier Science Ltd.