Climate change leads to increasing weathering cycles on landscapes and the built environment. Promotion of alternative energy sources such as geothermal energy, or underground CO2 storage, intensifies cyclic perturbations of the underground environment. Both lead to precipitation-dissolution cycles of salts, natural constituents of brines present inside porous rock. When precipitation occurs inside the pores, stresses build up which eventually crack the material, and thus degrade the rocks’ structure. This might be a positive outcome, e.g. increasing the production rate of a geothermal reservoir or underground storage capacity, or, on the contrary, be the cause of severe deterioration of natural building stones and coastal erosion.
What triggers rock dynamics up to fracturing during salt precipitation? Can we ultimately control, and thus engineer, this trigger? The ERC Starting Grant project “Precipitation triggered rock dynamics: the missing mesoscopic link” (PRD-Trigger) advocates that the answer lies at the mesoscale, this is, the scale of the pore network of the rock. Specifically, it will combine 4D X-ray micro-tomographic imaging with a mesoscopic numerical simulator integrated into the image analysis workflow to identify and hierarchize key factors in precipitation-induced damage. By acting on the identified trigger(s), damage control and crack healing will then be demonstrated on core-scale rocks. These advanced methods could be used to increase durability of building stones, for protection of coastal areas and historic stone-buildings, as well as to optimize geoengineering of the subsurface.
