Water-soluble melamine formaldehyde-free polycondensate products were prepared. The chemical structure of these polymers was confirmed with different spectroscopic techniques. The effects of these polymers on the rheological properties of the cement pastes were investigated. The rheological parameters (shear stress, yield stress, and plastic viscosity) were calculated with the Bingham model. The minislump of superplasticized cement pastes at different interval times (5, 30, 60, 90, and 120 min) was determined. The results showed that the new superplasticizers increased the fluidity and minislump of the cement pastes and reduced the minislump loss of the cement pastes not only at early ages (30 min) but also at later early ages (120 min). (c) 2005 Wiley Periodicals, Inc.