The dispersive action of synthesized comb-like copolymers including phosphonated or diphosphonated functions has been investigated using rheology and stability measurements. These investigations were performed by using calcite suspensions able to mimic the early-age behavior of cement paste. In addition, adsorption measurements were conducted to relate the adsorbed amount of copolymer to the effects on dispersion. The effectiveness of the studied copolymers was evaluated in different ionic media. It appears that diphosphonated structures with the shortest chain length are the most effective even in the context of ionic competition phenomenon. (C) 2018 Published by Elsevier B.V.