Quantitative characterization of the microstructure of fresh cement paste via random packing of polydispersed Platonic cement particles

On a microscopic scale, fresh cement paste is composed of random packing of irregular cement particles, and their initial packing behavior plays an important role in microstructural evolution. The preponderance of previous works has focused on the microstructure model by random packing of three-dimensional spheroidal particles, and little is known about non-spheroidal particles. In this paper, a modified cement particle size distribution function is used to facilitate the particle size distribution of convex polyhedral cement particles. Based on an overlapping detection algorithm, the microstructure model of fresh cement paste is simulated by the random sequential packing of Platonic cement particles of various sizes. Applying stereological tools and the serial sectioning analysis technique, the modeling microstructure composed of polydispersed Platonic cement particles is characterized and compared with that of ellipsoidal cement particles with various aspect ratios. The statistical results are investigated to evaluate the influence of cement particle shape on the microstructure of fresh cement paste. Finally, with the derived experimental and numerical results of microstructural parameters, the reliability of the statistical results is verified. (paper)