Mechanical and microstructural development of Carrara marble with pre-existing strain variation

A series of two-stage torsion experiments on Carrara marble were conducted to constrain the influence of known prior deformation on rheological response and microstructural evolution. Comparison with previous experimental data on Carrara marble flow and fabric evolution during single-stage torsion deformation experiments provided direct insights into the significance of initial deformation at various conditions. Our experiments were conducted at 727°C temperature and 300MPa confining pressure, while maintaining a constant strain rate of 3×10−4s−1 on the periphery of the cylindrical samples. Under these conditions, the marble is known to deform in power-law (n=6–10) ductile flow. All torsion experiments were performed with a Paterson type gas-medium testing machine equipped with a torsion actuator module.