Interfacial Fracture toughness of Barite Rocks

Abstract

This paper presents the results of an investigation of the interfacial fracture of barite rocks. The interfacial fracture toughness of barite (BaSO4) rocks is studied using Brazil disk testing. This is used to determine the mode mixity dependence of the interfacial fracture toughness at mode mixities between mode I and mode II conditions. The crack/microstructure interactions associated with the measured resistance-curve behavior are also elucidated along with the underlying toughening mechanisms (crack bridging and crack kinking/ deflection), which are revealed using optical microscopy. These are then incorporated into toughening models for estimating the fracture toughness/resistance-curve behavior at different mode mixities. The results show that the fracture toughness of barite rocks increases with increasing mode mixity. The implications of the results are then discussed for the applications of barite in oil and gas drilling, radiation shielding and aggregate materials.