When we simulate the hydration process of Portland cement, it is of significant importance to know the hydration mechanisms. Basically, there are two mechanisms for the hydration of Portland cement, viz. Topochemical and Through-Solution Reaction.
1 Topochemical Reaction Concept
In the late 1980s, Johnson and Jennings wrote a program which was based on the idea that cement hydration is considered as nucleation and growth of spherical particles in three-dimensional space.
With the development of computer technology, increasing attention is being paid to the modeling work of cementitious-based materials. Many researchers have been carrying out the research to better model the hydration of cement-based materials in the last decades. It is obvious that a cogent simulation of the hydration of cement-based materials has crucial role in construction industry, such as reducing tedious process of trial and error when doing experiments, facilitating the research of durability of concrete.