Progressive cracking of granite plate under uniaxial compression

Abstract

Progressive cracking of granite plate under uniaxial compression had been investigated by using a loading frame, which could be well equipped with optical microscope and video recorder. For revealing the details of the process at mineral grain level, a double replica technique had been employed to copy the mineral grains and the crack patterns on the specimen surface. Based on these replicas, observation study on the failure behavior of different minerals and fractal analysis on the crack patterns can be carried out. It is found that the cracking of granite appears locally and begins with the opening of quartz grain boundaries, which are nearly located in the compressive direction. Different minerals present their distinct behaviors during failure, which depend on their microstructure natures. The cracks developing in loading direction are dominant under uniaxial compression. Their propagation and coalescence finally result in the splitting failure of the specimen. Quartz acts as a crucial mineral to mainly control the failure of granite. The fractal dimension of surface crack pattern increases continuously with the cracking development before the final collapse takes place.