Molecular simulations of the initial stage's induction and formation process of N-A-S-H Gel based on NaOH-activated Metakaolin

In this work, the geopolymerization process was simulated by molecular dynamics based on the NaOH-activated metakaolin system. The structural changes and reaction kinetics during geopolymerization were systematically studied. The results show that the layered structure of MK was gradually destroyed, and the SiO4 and AlO4 monomers were formed. These monomers then reacted with each other to form the network-structured geopolymer. The Alumunum was dissolved prior to silicon and preferentially participated in geopolymerization reaction. The Al3+ acted as a charge-balanced ion to attract the surrounding oxygen linked to Si, making the O-SiO bond smaller. This study provides a theoretical basis for understanding the reaction kinetics and mechanism of geopolymerization.