Models to predict rheological properties

For the engineer that needs to design concrete for a specific application or for a specific placement method, the challenge lies in the prediction of the fresh concrete properties from its composition. Generally, there are procedures or codes to estimate the slump values depending on factors such as w/c ratio and chemical and mineral admixture dosage, but most of the time there is need for several trial batches.

A model that could predict the rheological parameters, yield stress and viscosity, from the composition or from minimal laboratory tests would be beneficial. Three promising models will be reviewed here:

• The compressible packing model (CPM) developed by de Larrard
• Simulation of flow of suspensions developed by NIST researchers
• A semi-empirical model based on the Krieger-Dougherty equation developed by Struble