Molecular dynamics study on accelerated carbonation of cement-based materials by supercritical carbon dioxide

LJ Chen and YH Ning and PC Li and G Pan and SZ Bu and L Gao, JOURNAL OF BUILDING ENGINEERING, 116, 114707 (2025).

DOI: 10.1016/j.jobe.2025.114707

Carbonation treatment of cement-based materials helps enhance material properties and facilitate carbon dioxide capture and sequestration. Therefore, it is crucial to investigate the influence mechanism of supercritical carbon dioxide (SC-CO2) environment on the carbonation process of cement-based materials, and to understand the regulatory effects of different reaction conditions on carbonation efficiency at the molecular level. In this study, molecular dynamics simulations were employed to investigate the early-stage polymerization process of calcium carbonate clusters in pore solution under SC-CO2 environment. Firstly, the reactive force field selected in this study was integrated and validated. Subsequently, the polymerization rate and final polymerization degree of calcium carbonate clusters under ambient environment and SC-CO2 environment were compared, and a series of temperature and pressure gradients were applied to study the influence of reaction conditions on the polymerization process. Additionally, the rate and activation energy of the polymerization reaction were calculated, and the local stress experienced by atoms during the reaction was analyzed. The results show that the SC-CO2 environment can significantly increase the polymerization degree of calcium carbonate clusters and reduce the reaction activation energy, with reaction temperature exerting a greater influence on the polymerization degree than reaction pressure. However, excessively high reaction temperature will convert carbonate ions into carbon dioxide, thereby affecting the formation of larger clusters in the system. Therefore, to ensure carbonation efficiency, the carbonation process should be conducted within a reasonable temperature and pressure range.

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