Alite hydration with alkalis
The continued drive to optimise the use of cement in concrete mixes has sparked an interest in the hydration of alite in an alkaline environment. Research has shown that the presence of alkalis such as Na and K during alite hydration results in a higher amount of hydrated products and matrix densification. By Carolina Giraldo Torres, Ariel Berrío, Cementos Argos & Oscar Mendoza Reales, Jorge Iván Tobón, Universidad Nacional de Colombia.
Almost two centuries after the discovery of Portland cement, there remains considerable ongoing research regarding the kinetic understanding of its synthesis and hydration processes. Many efforts are particularly focussed on the understanding of calcium silicates such as alite (C3S) and belite (C2S). These calcium silicates form hydrated calcium silicate, or C-S-H, the performance of which can be affected by internal and external factors of cement production and hydration. The main reason for this is that it accounts for 65-70 per cent of the total of hydrated products and, therefore, is the compound that is responsible for most of the properties of concrete mixes, both in their fresh and hardened states.1