Manufactured crushed sand: packing fraction prediction and influence on mortar rheology

River sand is a non-renewable resource that is becoming more and more scarce. For concrete industry, it is important to use alternatives like manufactured crushed sand or recycled sand. This article deals with the effect of manufactured crushed sand variability on the consistency of mortars. Two basic formulations are tested: the first corresponds to the mortar contained in a reference concrete and the second corresponds to the equivalent concrete mortar of the same concrete. For these formulations, the shear yield stress is measured to evaluate the mortars rheology with different crushed sand contents (from 30 to 100% of the total sand content) and origins. Eight crushed sands and three river sands are tested in this study. The loose and dense packing behaviour of reconstituted sands are measured and are linked to physical characteristics of the sand (surface roughness, morphology, and particle size distribution). The shear yield stress of the mortars is then predicted from the computed loose packing using homogenisation model. This work can be seen as a step forward to master the large variability in crushed sand and its effect on mortars consistency and rheology.