Characterization of the mesostructural organization of cement particles in fresh cement paste

Abstract

Comparative study on the mesostructures of fresh cement paste (FCP) in different dispersion mediums was carried out aiming at characterizing the structural organization of cement particles in FCP at a mesoscopic scale and establishing the correlation of mesostructure with rheological properties. For the first time, Morphologi G3 was adopted to in-situ characterize the mesostructure of FCP. Several dispersion mediums including air, deionized water, ethanol and an aqueous solution of ethanol were chosen to study the dispersion of cement particles in the selected mediums. Superplasticizers, as dispersing aids for cement particles, were added to change the dispersion of cement particles. Results show that Morphologi G3 with the high sensitivity and the high resolution is a powerful tool for in-situ characterization of the mesostructure of FCP by providing high-quality images associated with structural parameters. The structural parameters including particle size, circularity and fractal dimension of particle spatial distribution (Dpd) allow to quantitatively characterize the organization of cement particles in FCP at a mesoscopic scale, through which the relationship between the mesostructure and the rheological behavior of FCP was established. Higher fluidity signifies larger Dpd and circularity but a lower mean particle size. Moreover, the mean particle size and Dpd are more sensitive to indicate the fluidity change.