Rheological properties of cement-ground limestone paste with nano-CaCO₃

The rheological curves of the cement-ground limestone paste were determined by Rheolab QC rotation viscometer. Dynamic yield stress, consistency coefficient and rheological index of the paste were obtained by fitting the measured τ-γ curves based on Herschel-Bulkley model and thixotropy was characterized by the area of thixotropic hysteresis loop. The results indicate that:with the increase of ground limestone content, dynamic yield stress decreases gradually, consistency coefficient increases, while thixotropy increases and then decreases. The addition of nano-CaCO₃ has little effect on the rheological type of the cement-ground limestone paste and they both present a shear thinning behavior. With the increase of nano-CaCO₃ content, dynamic yield stress and consistency coefficient increase gradually, while thixotropy decreases. The addition of nano-CaCO₃ results in a poor rheological properties of the cement-ground limestone pastes but enhances its stability.