Importance of Precipitation in the Slowdown of Creep Behavior Induced by Pressure Solution

Pressure solution is a chemo-mechanical process, involving dissolution at grain/asperity contacts and precipitation away from them. It induces a compaction in time of rocks and sediments. The present study investigates numerically the impact of precipitation on the slowdown of creep behavior induced by pressure solution. A recently published framework, called the phase-field discrete element model, is carefully calibrated against existing indentation experiments and validated for other rate-limiting scenarios. It is shown that when precipitation is relatively slow, the slowdown of pressure solution is due to a chemical mechanism (accumulation of solute concentration within the pore space), whereas at fast precipitation, the slowdown is due to a mechanical mechanism (stress reduction at the contact).