Modelling the effect of mortar constituents on rheological properties

Concrete is a widely used construction material whose potential has not yet been fully exploited due to the lack of knowledge about its rheological behaviour. The mix composition is assumed to play a key role in controlling the rheological properties of concrete. Due to the extremely high proportion of finer particles in concrete, the investigation of the rheological properties of the mortar and paste phases is of major importance in understanding the rheological behaviour of concrete. Therefore, this paper systematically investigates the impact of water-to-cement ratio, sand content, and maximum sand size on the rheology of flowable mortars. It also explores the applicability of existing models for modeling these mortars.

The results, presented as a rheograph, reveal that a reduction of the w/c ratio and an increase in the sand solid content in the mortar leads to an increase in the rheological properties plastic viscosity and yield stress. Also, the addition of coarser sand in mortar compositions induces an increase in the maximum solid content and consequently a decrease in plastic viscosity. In addition, it shows that the Krieger-Dougherty and Liu models are appropriate enough for modelling polydisperse suspensions.