International Summit on Cement Hydration Kinetics

Jorge S. Dolado (NANOC-LABEIN)

Calcium silicate hydrated (C-S-H) gel is the principal binding phase of the cement paste and responsible for its strength. It is basically composed of silicate chains held together with CaO layers, where different guest ions can enter its structure. Here we will study he incorporation of aluminium into C-S-H gel by means of molecular dynamics simulations. In a first step we will simulate the formation of Al-free C-S-H particles by monitoring the polymerisation of silicic acids (Si(OH)₄) in presence of hydrated Portlandite molecules (Ca(OH)₂ 4H₂O). By a count of the number of formed Si-O-Si, Ca-OH and Si-OH bonds, the relationship with commonly employed structural models of calcium silicate hydrate (C-S-H) gels, such as 1.4-nm tobermorite and jennite, will be discussed. In a second step, we will include in our computational experiments different amounts of Al(OH)₃ and Na(OH) 5H₂O molecules to monitor the formation of C-A-S-H particles. The resulting structures will be analysed in terms of both the connectivity and the position of the aluminium atoms within the the aluminosilicate chains.

dolado-Presentation