Molecular simulation for the relationship between the functional groups of chemical admixtures and cement hydration product Ca (OH)2 in the grouting process

•Dealing with the relationship between land use and groundwater and protect the ecological environment.•Broken rock mass, cracks and water inrush can be blocked and reinforced by grouting.•Developing accurate quantitative models for the hydration of cement and predict the properties of grouting materials.•The adsorption processes of different functional groups on the surface of cement hydration products were explored by DFT calculations.•The mechanism of the cement hydration reaction and the influence of cement-based admixtures was revealed.