Autogenous healing in cement: A kinetic Monte Carlo simulation of CaCO3 precipitation

Autogenous healing induced by the dissolution of C-S-H and CH in a cracked cement paste was modelled in this study, at the mesoscale of tens of nanometres. The pore solution contains carbon dioxide (CO2) resulting in the precipitation of calcium carbonate (CaCO3) into the crack. The simulations were performed using MASKE, a recently developed coarse-grained Kinetic Monte Carlo framework where the molecules of the solid phases are modelled as mechanically interacting particles that can also precipitate and dissolve. The precipitation of CaCO3 molecules was initially observed in tiny gel pores within the C-S-H, but eventually extends completely filling the crack. The mechanical properties of the healed system were also investigated by straining the simulation box, computing the corresponding virial stress, and plotting the resulting stress-strain relationship.