Controlling fluidity of cement compositions.

An adjuvant for altering the fluidity of a cement composition contains a cement dispersing agent which is an aqueous polymer solution, wherein an antifoaming agent oxyalkylene base is dissolved or dispersed in particles having not more than 20muM of diameter. The polymer is preferably a polymer which contains units derived from an unsaturated carboxylic acid monomer and the polymer is preferably prepared in the presence of the antifoaming agent. Specific additional copolymers give particularly good results. The adjuvant allows good control of the fluidity of cement compositions and a period of extended storage.