Prediction of the yield stress of concrete considering the thickness of excess paste layer

Polycarboxylates in chemical admixtures are adsorbed onto the surface of cement particle, and the degree of their adsorption is related to the performance of concrete. Measuring total organic carbon (TOC), we demonstrated the amount of the consumed carbon is consistent regardless of the existence of aggregates. This result allows us to consider the effect of aggregates inclusion in a superplasticized cement paste. In a multiscale approach, concrete or mortar is considered as suspension of aggregates in cement paste. Excess paste layer covering aggregates in cement-based materials is considered taking a material property of the layer thickness in addition to the volume fraction of the aggregates. Finally, the yield stress of mortar or concrete can be predicted assuming that the layer thickness is constant regardless of the aggregate volume fraction.