Influence of the shape and roughness of inclusions on the rheological properties of a cementitious suspension

The influence of particle shape and surface roughness on the rheological properties of cementitious composites (cement paste plus coarse and fine particles) was investigated for mixtures of mortars and laboratory-made aggregates. The coarse particles were monosized spheres and cubes made from mortar, and monosized glass spheres, uncoated or roughened. The fine particles were uncoated or roughened monosized glass mini-spheres. The coarse particle mixtures were tested with a concrete rheometer to investigate separately the influence of overall particle shape and surface roughness on rheological properties as a function of aggregate concentration. The fine particle mixtures were tested with a paste rheometer to investigate the effect of surface roughness on flow at a smaller length scale using a different rheometer size and geometry. Results showed that shape had a large effect on plastic viscosity and, to a lesser degree, on Bingham yield stress. Surface roughness did not appear to have a significant effect on either property at the scale of roughness and particle volume fractions used. The tests were simulated using a validated computer model, which showed good agreement with the measured results