Effect of various plasticisers on viscous flow properties of natural pozzolanic cement pastes

The effect of various plasticisers (lignosulfonates and copolymers) on volcanic cement was assessed in this study. The volcanic cement was designed by substituting Portland cement with a natural volcanic pozzolan resulting from Andean volcanic activity. The best results (i.e. the volcanic cement pastes that showed shear-thickening viscous flow behaviour) were obtained when the zero-shear viscosity, minimum viscosity and shear rate for the onset of shear-thickening behaviour showed dependency on the paste concentration, Portland cement substitution and plasticiser concentration. The results were verified by the distorting effect of solid particles on the flow field.