This is a simulation of the change in the volume of the phases within a cylinder of cement paste (4 mm radius) that is attacked by carbonic acid, as in the experiments performed by Andrew Duguid. This calculation shows that there are changes in volume as the corrosion reaction proceeds, which is caused both by the creation/depletion of water molecules (see the Water animation) and by the mineral dissolution/precipitation (∆Vwat + ∆Vmin ≠ 0). This should affect the transport of pore fluid due to porosity change and water advection. But the latter mechanisms are not presently included (that is, the pressure gradient caused by the change in phase volume does not induce Darcy flow in the current implementation - but that will be done soon).