Mesoscopic Predictions of Cement Mortar Diffusivity by Analytical and Numerical Methods

Abstract

The purpose of this paper is to develop mesoscale models for predicting the diffusivity of cement mortar by numerical and analytical methods. The interfacial transition zone (ITZ) volume fraction was calculated by a three-dimensional geometric model with randomly distributed aggregates. The decrease in the water–cement ratio of the bulk cement paste due to the presence of ITZ was also considered. The results showed that the bulk paste porosity decreased significantly at a larger aggregate fraction. The mortar diffusivity was predicted by analytical and numerical methods. The predicted mortar diffusivity was in conformance with the measured diffusivity. It also indicated that the decreasing rate of the diffusivity as the increasing fraction of aggregate was dependent on the ITZ contents. The predicted results for the cement mortar with oblate or prolate aggregates showed that the diffusivity was larger as the shapes of the aggregates were more spherical than oblate or prolate.