In-pore solidification: from nanoscale origin to mesoscale damage

Mechanical and viscoelastic behavior of concrete crucially depends on cement hydrates, the glue of cement. Even more than the atomistic structure, the mesoscale amorphous texture of cement hydrates over hundreds of nanometers plays a crucial role for material properties. Common degradation mechanisms of concrete are Freeze-Thaw, Alkali-silica-Reaction and Delayed Ettringite Formation. These damage mechanisms occur under different thermodynamic conditions, nevertheless with necessary condition the suffiient saturation of cement's pore network with water. The damage occurs when a new phase solidifies inside the pore network of cement paste. In this talk, I present a unified computational framework that links the nanoscale origin of in pore crystallization to mesoscale damage in cement. Grand Canonical Monte Carlo and Molecular Dynamics simulations of in-pore crystallization were performed in the realistic structure and pore network of cement hydrates [1]. The results provide a new insight on how in-pore solidification creates cracks in cement paste and suggest solutions to mitigate the problem. 1. Ioannidou K. et al, The mesoscale texture of cement hydrates, Proceedings of National Academy of Science USA, 113 (8), 2029-2034 (2016)