Effects of particle packing density on the stability and rheology of self-consolidating concrete containing mineral admixtures

• We present a novel wet method for determination of packing density of SCC mixtures.
• The particle size distribution of all of solids in a SCC mixture is considered.
• The stability of SCC mixtures is evaluated in the horizontal and vertical movement.
• We apply a new experimental study for the measurement of solid velocity in SCC mixtures.

This paper presents an experimental study on the influence of packing density of solid particles on the stability and rheology of self-consolidating concrete (SCC). Also it is tried to address a new method for determination the packing density of SCC mixtures. Seven powder-types of SCC mixtures with different packing density were made with inclusion of silica fume, metakaolin or low activity-granulated blast furnace slag as a substitution of Portland cement. Results demonstrated that there is an optimal packing density about 0.804 and a little lower than maximum packing density of 0.807 with minimum static segregation and final plastic settlement. Moreover in the optimum packing density of particles, the calculated velocity and rheological properties of SCC are improved. The results emphasized that the effects of mineral admixtures are completely different in the static and dynamic segregation. Mineral admixtures reduced static segregation (SCC at rest in vertical state) but increase dynamic segregation (SCC at flowing in horizontal state). This finding shows that the cementitious binder content must be sufficient in flowing state to restraint from dynamic segregation.