Crystalline ASR products: Review of mineral candidates and molecular simulations of their atomic structures, thermodynamic data and thermoelastic properties

Several mineral analogues were proposed for ASR products, but no consensus exists on which ones best represent crystalline phases or could serve as templates for nanocrystalline or defective forms. This study reviews all structures reported in the literature for crystalline ASR products within the SiO2 –CaO–Na2 O–K2 O–H2 O system. The research develops the first atomic model database that includes both Na- and K-based ASR phases. These structures are simulated using Density Functional Theory (DFT) and classical Molecular Dynamics (MD). The work calculates and reports crucial data, including thermodynamic properties (heat capacity, entropy, and enthalpy of formation), self-diffusion coefficients of water and alkalis, elastic and thermoelastic properties. Furthermore, it quantifies the potential for generating crystallization pressure of each mineral analogue, which is key to ASR-induced expansion. Ultimately, the study discusses the structural and thermodynamic relevance of the investigated phases to determine their suitability as crystalline analogues for ASR reaction products.