Construction of a Molecular Dynamics Model of N-A-S-H Geopolymer Based on XRD Analysis

A geopolymer is a low-carbon cementitious material, and its condensation process is akin to the formation of inorganic polymers. The crystal phase of synthesized geopolymers was identified using XRD; the scattering peaks of amorphous phases were analyzed, and the zeolite minerals akin to different n(Si)/n(Al) geopolymers were determined. Based on this, a model structure of N-A-S-H geopolymers was established. The molecular dynamics structure of the model was simulated, and the density, energy, and bulk modulus of the model were calculated using three different force fields. According to the calculation results, the most suitable force field for N-A-S-H calculation is COMPASS III. In this study, all calculations were performed using MaterialsStudio 7.0. The research process introduces a new modeling method for geopolymers, similar to building C-S-H based on Tobermorite, which aids in advancing the molecular dynamics simulation of geopolymers.