Towards a multiscale rheological model of fresh cement paste: A population balance approach

In its fresh state, cement -the hydraulic binder responsible for the hardening of concrete -is a highly concentrated suspension in which nano and mesoscopic phenomena and their interactions determine its macroscopic rheological behaviour. This complexity creates significant challenges in the modelling of the material. In this work, a multiscale mod-elling framework capable of predicting rheological quantities of early age fresh cement pastes is proposed. Molecular Dynamics was used to obtain a high resolution picture of the colloidal interactions and their dependence on chemical composition. This informa-tion was subsequently scaled up and used within the aggregation and breakage kernels of a population balance model, which is then used to deduce rheological responses. Rheological, granulometric and spectroscopic measurements were performed to test and inform the model. Differences in the chemical composition of the studied samples could be used to produce satisfactory predictions of the observed viscosity curves.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.