Richardson’s model of tobermorite crystal lattice adapted to hydrated Portland cement crystal lattice

The quantitative phase analysis (QPA) of Portland cement X-ray diffraction patterns using the Rietveld method, shows the dominating contribution of Richardson's model of supercells with the water molecules embedded at 2- and 20- degree angles. It is found that the Ca4Si6O14(OH)4(H2O)4 supercell synthesized by using the tobermorite crystal lattice adapted to that of hydrated Portland cement, is stable. Ab initio calculations of the structural, thermodynamic, and mechanical characteristics are performed for the supercells with the full-profile structural characterization. The embedment of water molecules in supercells significantly changes the structural, thermodynamic, and mechanical characteristics of the initial model of the tobermorite crystal lattice. The investigated supercells can be used as reference standards in the QPA of Portland cement curing.