Microstructural pore changes in Gosford sandstone during compressive loading

X-ray CT scans were taken of Gosford sandstone under successively increasing pre-failure loads in unconfined compression to investigate the evolution of microstructural pore properties. It was found that the number of pores increased during early stages of loading, prior to a reduction of pore numbers at a point also corresponding to a slight stiffening of the stress-strain curve. Pore surface area, orientation and fractal dimension also showed subtle variations as loading progressed. Further, orientations of newly created pores tended to be near vertical and therefore perpendicular to the direction of maximum tensile strains. Energy dissipations associated with the creation of new surface and the redistribution of elastic stored energy through the newly fractured sandstone were back-calculated using the observed stress-strain response.A general increase in dissipation rate with the applied load was observed in the pre-failure region.