Effect of a nanoscale viscosity modifier on rheological properties of cement pastes and mechanical properties of mortars

The effect of a nanoscale viscosity modifier (called NP) on rheological properties of cement pastes and mechanical properties of mortars was experimentally studied. The morphology of NP agglomerates and its dispersed status was investigated by SEM. With different NP contents, the yield stress, plastic viscosity and thixotropy of pastes and the flexural strength and compressive strength of mortars were investigated and compared with plain cement paste and mortar at different water-to-cement ratios. The results illustrate that the incorporation of NP can increase plastic viscosity and yield stress of cement paste significantly. Its thixotropy varies simultaneously as well. The mechanical properties of mortars can be improved when the NP content is less than 1.0%. The reticulate structure formed by nanoscale rod-like NP particles with huge surface area in paste flocculates some water to modify the rheological properties of cement paste.