A microscopic investigation into the breakage behavior of calcareous origin grains in 1D compression

Abstract

Breakage in granular material has gained extensive research attention recently. This grain scale behavior would cause significant change to the macroscopic response. The development of x-ray micro-tomography technique makes it possible to non-destructively examine the microstructure of an assemblage at different stages of loading. In this study, micro-focused X-ray CT scanned images are used to visualize the development of grain crushing under one-dimensional compression. Initially uniformly graded carbonate grains are prepared into a tailor-made oedometric cell such that X-ray CT scanned images can be taken at different stages (loading and unloading) of the test. Image processing is carried out to isolate individual grains from the assemblage. The evolution of grain size and shape, and void size is examined based on the processed 3D images. The results show that the crushed grains are more rounded. The void space becomes smaller and varies within a narrower range as the compression continues.