Study of ion cluster reorientation process of geopolymerisation reaction using semi-empirical AM1 calculations

In this paper all the possible reaction pathways involved in ion clusters reorientation process of metakaolin based Geopolymeric cement were systemically investigated according to thermodynamic theory. The reaction energy of every possible reorientation pathway was also calculated using computational chemistry method-semi-empirical AM1 calculation. The optimum reorientation pathway was analyzed based on the energy-minimized principle. The calculation results showed that Si–Al hybrid reorientation should be primary reorientation pathway of Geopolymeric cement made with NaOH or KOH activated metakaolin. This viewpoint was also verified by Nuclear Magnetic Resonance Spectroscopy equipped with Magic Angle Spinning technique (MAS-NMR). In addition, the semi-empirical AM1 calculations revealed that the reorientation reaction is easier and stronger in NaOH solution than in KOH solution.