Microstructural modelling of cement-based materials via random packing of three-dimensional ellipsoidal particles

Random packing of particles in cement-based materials plays an important role in microstructural evolution. The preponderance of preview work has focused on the microstructural model by the random packing of spherical or two-dimensional elliptical particles, and little is known about three-dimensional ellipsoidal particles. In the present work, a new random packing model of three-dimensional ellipsoidal particles was developed to simulate microstructure of cement-based materials. It was based on a novel numerical algorithm for detecting the contact of ellipsoidal particles. The accuracy and reliability of the algorithm were verified by a visualization of the random packing of monodispersed ellipsoidal particles with rigid boundary conditions. According to these numerical algorithms, microstructural model of cement-based materials was constructed by the random packing of polydispersed ellipsoidal particles, of which sizes satisfy a specific distribution. Finally, applied stereological tools and serial sectioning analysis technique, microstructure of cement pastes, composed of ellipsoidal cement particles, was characterized and compared with that of spherical cement particles.