In this article, we have highlighted two key aspects of concrete rheology: (1) the agglomeration of the finer particles and the role of dispersants to counter this agglomeration and (2) the granular nature of concrete and the role of particle size distributions on the rheological properties of concrete.
Mastering both aspects has led to significant progress in concrete technology, raising expectations for concrete properties and highlighting questions of robustness. Consequently, there is an increased need for predicting concrete properties and their variation.
In this context, modeling can play a crucial role. The work presented shows promising results in its ability to account for the three-dimensional shapes of particles. While good predictions of plastic viscosity have been obtained, more work is needed to accurately measure the role of yield stress. Ultimately, the model should use structural information about the superplasticizer molecule to properly evaluate interparticle forces. Such tools will not only allow better use of existing materials but will also help admixture producers design superplasticizers with better performance and enhanced robustness.
The utility and predictive capability of the models will improve with further advances in our ability to quantify interparticle forces and formulate multiscale models. In the long term, to properly describe cement rheology, the inclusion of other features such as the reactivity of cement and the perturbation of dispersant efficiency though intercalation or adsorption competition from other species needs to be taken into account.