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.
Many models are available to model the hydration process and microstructure of cement-based materials. According the simplifications of hydration models, two main approaches could be classified, viz. continuous approach and discretization approach. Because of the complexity of real hardening cement-based materials, each model is based on certain assumptions that aim to simplify the complexity of real cement microstructure and its interactions.
The advantages of continuous approach are resolution free and no requirement to divide features of microstructure into smaller elements. Particles are normally assumed as sphere shapes. The assumption of sphere demands less information to describe particles when modeling compared with other shapes, thus resulting in the calculation of the distance between two particles fast. This method also preserves information about features that scale over several orders of magnitude, viz. from micrometers to millimeters. However, the drawback of this method is that the geometry of microstructure is altered.
The principle of discretization approach is similar to finite element method. The entire volume of the microstructure is filled with smaller elements which are placed with their faces in contact. By means of a certain algorithm, the hydration and microstructure development of cement could be simulated.