Ice formation in the cement paste: a coarse-grained model of precipitation-induced damage in a porous matrix at the mesoscale

Abstract Concrete degradation is often caused by the formation of new solid phases within the pore network of cement, leading to crack formation and propagation, ultimately resulting in structural damage. In this study, we propose a coarse-grained particle-based model to simulate solid growth in porous networks. The model combines Grand Canonical Monte Carlo simulations for solid precipitation with molecular dynamics simulations in the isobaric–isothermal ensemble to capture crack formation. The model is applied to investigate the formation of ice in cement paste during freeze-thaw cycles, focusing specifically on the freezing stage. The simulation results revealed a two-stage growth process: an initial lag phase where isolated ice clusters grow within pores, followed by a rapid growth phase during which the ice clusters percolate through the pore network. This percolation is associated with significant volume expansion and fracture of the cement paste, providing insights into the mechanisms driving freeze-thaw damage in cement-based materials.