The initial stages of cement hydration at the molecular level.

Cement hydration is crucial for the strength development of cement-based materials; however, the mechanism that underlies this complex reaction remains poorly understood at the molecular level. An in-depth understanding of cement hydration is required for the development of environmentally friendly cement and consequently the reduction of carbon emissions in the cement industry. Here, we use molecular dynamics simulations with a reactive force field to investigate the initial hydration processes of tricalcium silicate (C 3 S) and dicalcium silicate (C 2 S) up to 40 ns. Our simulations provide theoretical support for the rapid initial hydration of C 3 S compared to C 2 S at the molecular level. The dissolution pathways of calcium ions in C 3 S and C 2 S are revealed, showing that, two dissolution processes are required for the complete dissolution of calcium ions in C 3 S. Our findings promote the understanding of the calcium dissolution stage and serve as a valuable reference for the investigation of the initial cement hydration.